1
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Jeon D, Hill E, McNeel DG. Toll-like receptor agonists as cancer vaccine adjuvants. Hum Vaccin Immunother 2024; 20:2297453. [PMID: 38155525 PMCID: PMC10760790 DOI: 10.1080/21645515.2023.2297453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 12/16/2023] [Indexed: 12/30/2023] Open
Abstract
Cancer immunotherapy has emerged as a promising strategy to treat cancer patients. Among the wide range of immunological approaches, cancer vaccines have been investigated to activate and expand tumor-reactive T cells. However, most cancer vaccines have not shown significant clinical benefit as monotherapies. This is likely due to the antigen targets of vaccines, "self" proteins to which there is tolerance, as well as to the immunosuppressive tumor microenvironment. To help circumvent immune tolerance and generate effective immune responses, adjuvants for cancer vaccines are necessary. One representative adjuvant family is Toll-Like receptor (TLR) agonists, synthetic molecules that stimulate TLRs. TLRs are the largest family of pattern recognition receptors (PRRs) that serve as the sensors of pathogens or cellular damage. They recognize conserved foreign molecules from pathogens or internal molecules from cellular damage and propel innate immune responses. When used with vaccines, activation of TLRs signals an innate damage response that can facilitate the development of a strong adaptive immune response against the target antigen. The ability of TLR agonists to modulate innate immune responses has positioned them to serve as adjuvants for vaccines targeting infectious diseases and cancers. This review provides a summary of various TLRs, including their expression patterns, their functions in the immune system, as well as their ligands and synthetic molecules developed as TLR agonists. In addition, it presents a comprehensive overview of recent strategies employing different TLR agonists as adjuvants in cancer vaccine development, both in pre-clinical models and ongoing clinical trials.
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Affiliation(s)
- Donghwan Jeon
- Department of Oncology, University of Wisconsin Carbone Cancer Center, Madison, WI, USA
| | - Ethan Hill
- Department of Medicine, University of Wisconsin Carbone Cancer Center, Madison, WI, USA
| | - Douglas G. McNeel
- Department of Medicine, University of Wisconsin Carbone Cancer Center, Madison, WI, USA
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2
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Candan B, Karakuyu NF, Gülle K, Sarman E, Ulusoy Karatopuk D. Beneficial Effects of Selenium on Kidney Injury via Nf-Kb and Aquaporin-1 Levels. Biol Trace Elem Res 2024; 202:3653-3661. [PMID: 37910264 DOI: 10.1007/s12011-023-03928-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 10/22/2023] [Indexed: 11/03/2023]
Abstract
Systemic inflammation is a serious condition that can affect various tissues and organs, such as the kidneys, and can be life-threatening. Selenium (Se) is an antioxidant and anti-inflammatory trace element. In this study, we aimed to examine the effects of Se, which has antioxidant and anti-inflammatory properties, on lipopolysaccharide (LPS)-induced kidney damage to maintain aquaporin-1 (AQP-1) levels. Four experimental rat groups (n = 8) consisting of the control, LPS alone, LPS + Se, and Se alone were so applied for 7 consecutive days. Upon sacrifice, histopathological results, diagnostic markers of kidney functions, oxidative stress, and inflammation were analyzed. Our results showed that LPS induced mononuclear cell infiltration, cellular residue, and protein deposition in the kidney proximal tubules, and also decreased total antioxidant status levels and increased total antioxidant status and oxidative stress index values. LPS increased the level of creatinine, increased the level of Nuclear Factor kappa B, which has an important role in the inflammation process, and decreased the levels of AQP-1 due to the damage it caused. Se has shown its effect by reversing all these situations. This data suggests that Se can be used as an additive to mitigate LPS-induced toxicity in the kidney.
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Affiliation(s)
- B Candan
- Department of Anatomy, School of Medicine, Alanya Alaaddin Keykubat University, Alanya, Turkey
| | - N F Karakuyu
- Department of Pharmacology, Faculty of Pharmacy, Suleyman Demirel University, Isparta, Turkey.
| | - K Gülle
- Department of Histology and Embryology, School of Medicine, Suleyman Demirel University, Isparta, Turkey
| | - E Sarman
- Department of Histology and Embryology, School of Medicine, Afyonkarahisar Health Sciences University, Afyonkarahisar, Turkey
| | - D Ulusoy Karatopuk
- Department of Histology and Embryology, School of Medicine, Suleyman Demirel University, Isparta, Turkey
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3
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Zhang LW, Cui CA, Liu C, Sun LP, Ouyang YN, Li LF, Zhang DL, Yu HL. Auraptene-ameliorating depressive-like behaviors induced by lipopolysaccharide combined with chronic unpredictable mild stress in mice mitigate hippocampal neuroinflammation mediated by microglia. Int Immunopharmacol 2024; 136:112330. [PMID: 38823180 DOI: 10.1016/j.intimp.2024.112330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 05/10/2024] [Accepted: 05/20/2024] [Indexed: 06/03/2024]
Abstract
An inflammatory response is one of the pathogeneses of depression. The anti-inflammatory and neuroprotective effects of auraptene have previously been confirmed. We established an inflammatory depression model by lipopolysaccharide (LPS) injection combined with unpredictable chronic mild stress (uCMS), aiming to explore the effects of auraptene on depressive-like behaviors in adult mice. Mice were divided into a control group, vehicle group, fluoxetine group, celecoxib group, and auraptene group. Then, behavioral tests were conducted to evaluate the effectiveness of auraptene in ameliorating depressive-like behavior. Cyclooxygenase-2 (COX-2), C-reactive protein (CRP), tumor necrosis factor (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) were examined by ELISA. Interleukin-10 (IL-10), interleukin-4 (IL-4), and transforming growth factor-β (TGF-β) were examined by protein chip technology. The morphology of microglia was observed by the immunohistochemical method. The data showed that, compared with the control group, the vehicle group mice exhibited a depressive-like behavioral phenotype, accompanied by an imbalance in inflammatory cytokines and the activation of microglia in the hippocampus. The depressive behaviors of the auraptene group's mice were significantly alleviated, along with the decrease in pro-inflammatory factors and increase in anti-inflammatory factors, while the activation of microglia was inhibited in the hippocampus. Subsequently, we investigated the role of auraptene in vitro-cultured BV-2 cells treated with LPS. The analysis showed that auraptene downregulated the expression of IL-6, TNF-α, and NO, and diminished the ratio of CD86/CD206. The results showed that auraptene reduced the excessive phagocytosis and ROS production of LPS-induced BV2 cells. In conclusion, auraptene relieved depressive-like behaviors in mice probably via modulating hippocampal neuroinflammation mediated by microglia.
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Affiliation(s)
- Lu-Wen Zhang
- Department of Functional Science, College of Medicine, Yanbian University, Yanji, Jilin, PR China
| | - Chun-Ai Cui
- Department of Anatomy, College of Medicine, Yanbian University, Yanji, Jilin, PR China
| | - Chao Liu
- Department of Neurology, Yanbian University Affiliated Hospital, Yanji, Jilin, PR China
| | - Lian-Ping Sun
- Department of Morphological Experiment, College of Medicine, Yanbian University, Yanji, Jilin, PR China
| | - Yi-Nan Ouyang
- Department of Morphological Experiment, College of Medicine, Yanbian University, Yanji, Jilin, PR China
| | - Long-Fei Li
- Department of Functional Science, College of Medicine, Yanbian University, Yanji, Jilin, PR China
| | - Dong-Liang Zhang
- Department of Functional Science, College of Medicine, Yanbian University, Yanji, Jilin, PR China
| | - Hai-Ling Yu
- Department of Functional Science, College of Medicine, Yanbian University, Yanji, Jilin, PR China.
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4
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Li W, Tao Z, Zhou M, Jiang H, Wang L, Ji B, Zhao Y. Antibiotic adjuvants against multidrug-resistant Gram-negative bacteria: important component of future antimicrobial therapy. Microbiol Res 2024; 287:127842. [PMID: 39032266 DOI: 10.1016/j.micres.2024.127842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 07/13/2024] [Accepted: 07/14/2024] [Indexed: 07/23/2024]
Abstract
The swift emergence and propagation of multidrug-resistant (MDR) bacterial pathogens constitute a tremendous global health crisis. Among these pathogens, the challenge of antibiotic resistance in Gram-negative bacteria is particularly pressing due to their distinctive structure, such as highly impermeable outer membrane, overexpressed efflux pumps, and mutations. Several strategies have been documented to combat MDR Gram-negative bacteria, including the structural modification of existing antibiotics, the development of antimicrobial adjuvants, and research on novel targets that MDR bacteria are sensitive to. Drugs functioning as adjuvants to mitigate resistance to existing antibiotics may play a pivotal role in future antibacterial therapy strategies. In this review, we provide a brief overview of potential antibacterial adjuvants against Gram-negative bacteria and their mechanisms of action, and discuss the application prospects and potential for bacterial resistance to these adjuvants, along with strategies to reduce this risk.
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Affiliation(s)
- Wenwen Li
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province 110016, PR China
| | - Zhen Tao
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province 110016, PR China
| | - Motan Zhou
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province 110016, PR China
| | - Huilin Jiang
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province 110016, PR China
| | - Liudi Wang
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province 110016, PR China
| | - Bingjie Ji
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province 110016, PR China
| | - Yongshan Zhao
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province 110016, PR China.
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5
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Zhang T, Lyu J, Yang B, Yun SD, Scott E, Zhao M, Laganowsky A. Native mass spectrometry and structural studies reveal modulation of MsbA-nucleotide interactions by lipids. Nat Commun 2024; 15:5946. [PMID: 39009687 PMCID: PMC11251056 DOI: 10.1038/s41467-024-50350-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 07/07/2024] [Indexed: 07/17/2024] Open
Abstract
The ATP-binding cassette (ABC) transporter, MsbA, plays a pivotal role in lipopolysaccharide (LPS) biogenesis by facilitating the transport of the LPS precursor lipooligosaccharide (LOS) from the cytoplasmic to the periplasmic leaflet of the inner membrane. Despite multiple studies shedding light on MsbA, the role of lipids in modulating MsbA-nucleotide interactions remains poorly understood. Here we use native mass spectrometry (MS) to investigate and resolve nucleotide and lipid binding to MsbA, demonstrating that the transporter has a higher affinity for adenosine 5'-diphosphate (ADP). Moreover, native MS shows the LPS-precursor 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo)2-lipid A (KDL) can tune the selectivity of MsbA for adenosine 5'-triphosphate (ATP) over ADP. Guided by these studies, four open, inward-facing structures of MsbA are determined that vary in their openness. We also report a 2.7 Å-resolution structure of MsbA in an open, outward-facing conformation that is not only bound to KDL at the exterior site, but with the nucleotide binding domains (NBDs) adopting a distinct nucleotide-free structure. The results obtained from this study offer valuable insight and snapshots of MsbA during the transport cycle.
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Affiliation(s)
- Tianqi Zhang
- Department of Chemistry, Texas A&M University, College Station, TX, USA
| | - Jixing Lyu
- Department of Chemistry, Texas A&M University, College Station, TX, USA
| | - Bowei Yang
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - Sangho D Yun
- Department of Chemistry, Texas A&M University, College Station, TX, USA
| | - Elena Scott
- Department of Chemistry, Texas A&M University, College Station, TX, USA
| | - Minglei Zhao
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University, College Station, TX, USA.
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6
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Takizawa F, Domon H, Hirayama S, Isono T, Sasagawa K, Yonezawa D, Ushida A, Tsutsuura S, Miyoshi T, Mimuro H, Yoshida A, Tabeta K, Terao Y. Effective degradation of various bacterial toxins using ozone ultrafine bubble water. PLoS One 2024; 19:e0306998. [PMID: 38985791 PMCID: PMC11236168 DOI: 10.1371/journal.pone.0306998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 06/26/2024] [Indexed: 07/12/2024] Open
Abstract
Infectious and foodborne diseases pose significant global threats, with devastating consequences in low- and middle-income countries. Ozone, derived from atmospheric oxygen, exerts antimicrobial effects against various microorganisms, and degrades fungal toxins, which were initially recognized in the healthcare and food industries. However, highly concentrated ozone gas can be detrimental to human health. In addition, ozonated water is unstable and has a short half-life. Therefore, ultrafine-bubble technology is expected to overcome these issues. Ultrafine bubbles, which are nanoscale entitles that exist in water for considerable durations, have previously demonstrated bactericidal effects against various bacterial species, including antibiotic-resistant strains. This present study investigated the effects of ozone ultrafine bubble water (OUFBW) on various bacterial toxins. This study revealed that OUFBW treatment abolished the toxicity of pneumolysin, a pneumococcal pore-forming toxin, and leukotoxin, a toxin that causes leukocyte injury. Silver staining confirmed the degradation of pneumolysin, leukotoxin, and staphylococcal enterotoxin A, which are potent gastrointestinal toxins, following OUFB treatment. In addition, OUFBW treatment significantly inhibited NF-κB activation by Pam3CSK4, a synthetic triacylated lipopeptide that activates Toll-like receptor 2. Additionally, OUFBW exerted bactericidal activity against Staphylococcus aureus, including an antibiotic-resistant strain, without displaying significant toxicity toward human neutrophils or erythrocytes. These results suggest that OUFBW not only sterilizes bacteria but also degrades bacterial toxins.
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Affiliation(s)
- Fumio Takizawa
- Division of Microbiology and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
- Division of Periodontology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hisanori Domon
- Division of Microbiology and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
- Center for Advanced Oral Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Satoru Hirayama
- Division of Microbiology and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Toshihito Isono
- Division of Microbiology and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Karin Sasagawa
- Division of Microbiology and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
- Division of Periodontology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Daisuke Yonezawa
- Division of Oral Science for Health Promotion, Niigata University, Niigata, Japan
| | - Akiomi Ushida
- Institute of Science and Technology, Niigata University, Niigata, Japan
| | | | - Tomohiro Miyoshi
- Division of Genome-Wide Infectious Diseases, Research Center for GLOBAL and LOCAL Infectious Disease, Oita University, Oita, Japan
| | - Hitomi Mimuro
- Division of Genome-Wide Infectious Diseases, Research Center for GLOBAL and LOCAL Infectious Disease, Oita University, Oita, Japan
| | - Akihiro Yoshida
- Department of Oral Microbiology, Matsumoto Dental University, Nagano, Japan
| | - Koichi Tabeta
- Division of Periodontology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yutaka Terao
- Division of Microbiology and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
- Center for Advanced Oral Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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7
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Chakraborty A, Alsharqi L, Kostrzewa M, Armstrong-James D, Larrouy-Maumus G. Intact cell lipidomics using the Bruker MBT lipid Xtract assay allows the rapid detection of glycosyl-inositol-phospho-ceramides from Aspergillus fumigatus. Mol Omics 2024; 20:390-396. [PMID: 38623711 PMCID: PMC11228930 DOI: 10.1039/d4mo00030g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Accepted: 03/27/2024] [Indexed: 04/17/2024]
Abstract
Glycosyl-inositol-phospho-ceramides (GIPCs) or glycosylphosphatidylinositol-anchored fungal polysaccharides are major lipids in plant and fungal plasma membranes and play an important role in stress adaption. However, their analysis remains challenging due to the multiple steps involved in their extraction and purification prior to mass spectrometry analysis. To address this challenge, we report here a novel simplified method to identify GIPCs from Aspergillus fumigatus using the new Bruker MBT lipid Xtract assay. A. fumigatus reference strains and clinical isolates were cultured, harvested, heat-inactivated and suspended in double-distilled water. A fraction of this fungal preparation was then dried in a microtube, mixed with an MBT lipid Xtract matrix (Bruker Daltonik, Germany) and loaded onto a MALDI target plate. Analysis was performed using a Bruker MALDI Biotyper Sirius system in the linear negative ion mode. Mass spectra were scanned from m/z 700 to m/z 2 000. MALDI-TOF MS analysis of cultured fungi showed a clear signature of GIPCs in Aspergillus fumigatus reference strains and clinical isolates. Here, we have demonstrated that routine MALDI-TOF in the linear negative ion mode combined with the MBT lipid Xtract is able to detect Aspergillus fumigatus GIPCs.
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Affiliation(s)
- Aishani Chakraborty
- Centre for Bacterial Resistance Biology, Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, SW7 2AZ, UK.
| | - Leila Alsharqi
- Centre for Bacterial Resistance Biology, Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK.
| | | | - Darius Armstrong-James
- Centre for Bacterial Resistance Biology, Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK.
| | - Gerald Larrouy-Maumus
- Centre for Bacterial Resistance Biology, Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, SW7 2AZ, UK.
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8
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Zeng Y, Li P, Liu S, Shen M, Liu Y, Zhou X. Salmonella enteritidis acquires phage resistance through a point mutation in rfbD but loses some of its environmental adaptability. Vet Res 2024; 55:85. [PMID: 38970094 PMCID: PMC11227202 DOI: 10.1186/s13567-024-01341-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 04/07/2024] [Indexed: 07/07/2024] Open
Abstract
Phage therapy holds promise as an alternative to antibiotics for combating multidrug-resistant bacteria. However, host bacteria can quickly produce progeny that are resistant to phage infection. In this study, we investigated the mechanisms of bacterial resistance to phage infection. We found that Rsm1, a mutant strain of Salmonella enteritidis (S. enteritidis) sm140, exhibited resistance to phage Psm140, which was originally capable of lysing its host at sm140. Whole genome sequencing analysis revealed a single nucleotide mutation at position 520 (C → T) in the rfbD gene of Rsm1, resulting in broken lipopolysaccharides (LPS), which is caused by the replacement of CAG coding glutamine with a stop codon TAG. The knockout of rfbD in the sm140ΔrfbD strain caused a subsequent loss of sensitivity toward phages. Furthermore, the reintroduction of rfbD in Rsm1 restored phage sensitivity. Moreover, polymerase chain reaction (PCR) amplification of rfbD in 25 resistant strains revealed a high percentage mutation rate of 64% within the rfbD locus. We assessed the fitness of four bacteria strains and found that the acquisition of phage resistance resulted in slower bacterial growth, faster sedimentation velocity, and increased environmental sensitivity (pH, temperature, and antibiotic sensitivity). In short, bacteria mutants lose some of their abilities while gaining resistance to phage infection, which may be a general survival strategy of bacteria against phages. This study is the first to report phage resistance caused by rfbD mutation, providing a new perspective for the research on phage therapy and drug-resistant mechanisms.
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Affiliation(s)
- Yukun Zeng
- College of Veterinary Medicine, Institute of Comparative Medicine, Yangzhou University, Yangzhou, 225009, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Ping Li
- College of Veterinary Medicine, Institute of Comparative Medicine, Yangzhou University, Yangzhou, 225009, China
| | - Shenglong Liu
- College of Veterinary Medicine, Institute of Comparative Medicine, Yangzhou University, Yangzhou, 225009, China
| | - Mangmang Shen
- College of Veterinary Medicine, Institute of Comparative Medicine, Yangzhou University, Yangzhou, 225009, China
| | - Yuqing Liu
- Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Jinan, 250100, China.
| | - Xin Zhou
- College of Veterinary Medicine, Institute of Comparative Medicine, Yangzhou University, Yangzhou, 225009, China.
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China.
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China.
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9
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Esmaeilpour K, Jafari E, Rostamabadi F, Khaleghi M, Akhgarandouz F, Hosseini M, Najafipour H, Khodadoust M, Sheibani V, Rajizadeh MA. Myrtenol Inhalation Mitigates Asthma-Induced Cognitive Impairments: an Electrophysiological, Behavioral, Histological, and Molecular Study. Mol Neurobiol 2024; 61:4891-4907. [PMID: 38148370 DOI: 10.1007/s12035-023-03863-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 11/29/2023] [Indexed: 12/28/2023]
Abstract
Asthma is an inflammatory disorder with significant health problems. It generally affects the lungs but can also impact brain performance via several mechanisms. Some investigations have proposed that asthma impairs cognition. This study assessed the impacts of myrtenol as a monoterpene on cognitive disorders following asthma at behavioral, molecular, and synaptic levels. Asthma was induced by injection and inhalation of ovalbumin (OVA). Male Wistar rats were allocated to five groups: control, asthma, asthma/vehicle, asthma/myrtenol, and asthma/budesonide. Myrtenol (8 mg/kg) or budesonide (160 μg/kg) was administered through inhalation once a day for 1 week, and at the end of the inhalation period, behavioral tests (MWM and Open Field), field potential recording, hippocampal brain-derived neurotrophic factor (BDNF), IL1β (ELISA), and NFκB measurement (Western blot) were performed to evaluate cognitive performance. Moreover, H&E (hematoxylin and eosin) staining was used for hippocampus histological evaluation. Myrtenol improved spatial learning, memory, LTP (long-term potentiation) impairments, and anxiety-like behaviors following asthma. Myrtenol inhalation increased the BDNF level and decreased the IL1β level and NFκB expression in the hippocampus of the asthmatic rats. The neuronal damage in the hippocampus following allergic asthma was alleviated via myrtenol administration. Myrtenol, as an herbal extract, protects the hippocampus from asthma consequences. Our observations revealed that myrtenol can improve spatial learning, memory, synaptic plasticity impairments, and anxiety-like behaviors following asthma. We believe that these ameliorating effects of myrtenol can be attributed to inflammation suppression and increased BDNF in the hippocampus.
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Affiliation(s)
- Khadijeh Esmaeilpour
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
- Physics and Astronomy Department, University of Waterloo, Waterloo, ON, Canada
| | - Elham Jafari
- Pathology and Stem Cell Research Center, Department of Pathology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Fahimeh Rostamabadi
- Noncommunicable Diseases Research Center, Bam University of Medical Sciences, Bam, Iran
| | - Mina Khaleghi
- Physiology Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Faezeh Akhgarandouz
- Department of Biology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran
| | - Maryam Hosseini
- Department of Neuroscience, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hamid Najafipour
- Cardiovascular Research Center, Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences, Kerman, Iran
| | - Mahdi Khodadoust
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Vahid Sheibani
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran.
| | - Mohammad Amin Rajizadeh
- Physiology Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran.
- Department of Neuroscience, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran.
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10
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Henningsen K, Martinez I, Costa RJS. Exertional Stress-induced Pathogenic Luminal Content Translocation - Friend or Foe? Int J Sports Med 2024; 45:559-571. [PMID: 38286406 DOI: 10.1055/a-2235-1629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2024]
Abstract
The incidence of perturbed gastrointestinal integrity, as well as resulting systemic immune responses and gastrointestinal symptoms, otherwise known as exercised-induced gastrointestinal syndrome (EIGS), is common among individuals who partake in prolonged exercise. EIGS may cause the translocation of pathogenic material, including whole bacteria and bacterial endotoxins, from the lumen into circulation, which may progress into clinical consequences such as sepsis, and potentially subsequent fatality. However, further investigation is warranted to assess the possibility of food allergen and/or digestive enzyme luminal to circulatory translocation in response to exercise, and the clinical consequences. Findings from this narrative literature review demonstrate evidence that whole bacteria and bacterial endotoxins translocation from the gastrointestinal lumen to systemic circulation occurs in response to exercise stress, with a greater propensity of translocation occurring with accompanying heat exposure. It has also been demonstrated that food allergens can translocate from the lumen to systemic circulation in response to exercise stress and initiate anaphylaxis. To date, no research investigating the effect of exercise on the translocation of digestive enzymes from the lumen into systemic circulation exists. It is evident that EIGS and consequential pathogenic translocation presents life-threatening clinical implications, warranting the development and implementation of effective management strategies in at-risk populations.
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Affiliation(s)
- Kayla Henningsen
- Nutrition Dietetics & Food, Monash University Faculty of Medicine Nursing and Health Sciences, Notting Hill, Australia
| | - Isabel Martinez
- Nutrition Dietetics & Food, Monash University Faculty of Medicine Nursing and Health Sciences, Notting Hill, Australia
| | - Ricardo J S Costa
- Nutrition Dietetics & Food, Monash University Faculty of Medicine Nursing and Health Sciences, Notting Hill, Australia
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11
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Rahman ASMZ, Syroegin EA, Novomisky Nechcoff J, Devarajan A, Polikanov YS, Cardona ST. Rationally Designed Pooled CRISPRi-Seq Uncovers an Inhibitor of Bacterial Peptidyl-tRNA Hydrolase. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.02.592284. [PMID: 38979387 PMCID: PMC11230203 DOI: 10.1101/2024.05.02.592284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Pooled knockdown libraries of essential genes are useful tools for elucidating the mechanisms of action of antibacterial compounds, a pivotal step in antibiotic discovery. However, achieving genomic coverage of antibacterial targets poses a challenge due to the uneven proliferation of knockdown mutants during pooled growth, leading to the unintended loss of important targets. To overcome this issue, we describe the construction of CIMPLE ( C RISPR i - m ediated p ooled library of e ssential genes), a rationally designed pooled knockdown library built in a model antibiotic-resistant bacteria, Burkholderia cenocepacia. By analyzing growth parameters of clonal knockdown populations of an arrayed CRISPRi library, we predicted strain depletion levels during pooled growth and adjusted mutant relative abundance, approaching genomic coverage of antibacterial targets during antibiotic exposure. We first benchmarked CIMPLE by chemical-genetic profiling of known antibacterials, then applied it to an uncharacterized bacterial growth inhibitor from a new class. CRISPRi-Seq with CIMPLE, followed by biochemical validation, revealed that the novel compound targets the peptidyl-tRNA hydrolase (Pth). Overall, CIMPLE leverages the advantages of arrayed and pooled CRISPRi libraries to uncover unexplored targets for antibiotic action. Summary Bacterial mutant libraries in which antibiotic targets are downregulated are useful tools to functionally characterize novel antimicrobials. These libraries are used for chemical-genetic profiling as target-compound interactions can be inferred by differential fitness of mutants during pooled growth. Mutants that are functionally related to the antimicrobial mode of action are usually depleted from the pool upon exposure to the drug. Although powerful, this method can fail when the unequal proliferation of mutant strains before exposure causes mutants to fall below the detection level in the library pool. To address this issue, we constructed an arrayed essential gene mutant library (EGML) in the antibiotic-resistant bacterium Burkholderia cenocepacia using CRISPR interference (CRISPRi) and analyzed the growth parameters of individual mutant strains. We then modelled depletion levels during pooled growth and used the model to rationally design an optimized CRISPR interference-mediated pooled library of essential genes (CIMPLE). By adjusting the initial inoculum of the knockdown mutants, we achieved coverage of the bacterial essential genome with mutant sensitization. We exposed CIMPLE to a recently discovered antimicrobial of a novel class and discovered it inhibits the peptidyl-tRNA hydrolase, an essential bacterial enzyme. In summary, we demonstrate the utility of CIMPLE and CRISPRi-Seq to uncover the mechanism of action of novel antimicrobial compounds. Graphical abstract
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Akahane S, Matsuura H, Kaido T, Usami Y, Ishimine N, Uehara T, Yamauchi K. Apolipoprotein E-containing lipoproteins and their extracellular interactions with LRP1 affect LPS-induced inflammation. Biol Chem 2024; 405:383-393. [PMID: 38488124 DOI: 10.1515/hsz-2024-0018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 03/03/2024] [Indexed: 06/02/2024]
Abstract
The linkage between low-density lipoprotein receptor-related protein (LRP)1-mediated metabolism of apolipoprotein (apo) E-containing lipoproteins (apoE-LP) and the lipopolysaccharide (LPS)-induced inflammatory response contributes to the pathogenesis of sepsis; however, the underlying mechanisms are unclear. Therefore, in this study, the effects of apoE-LP and their constituents on the mRNA expression of interleukin (IL)-6 and LRP1 were evaluated using a culture system of human fibroblasts supplemented with LPS and apoE-containing emulsion particles (apoE-EP). The affinity of apoE-LP for LPS was examined using the interaction between fluorescence-labeled LPS and serum lipoprotein fractions. LPS-induced inflammation significantly upregulated the mRNA expression of IL-6 and LRP1. This upregulation was markedly suppressed by pre-incubation of LPS with apoE-EP or its constituents (apoE or EP). The suppressive effect of apoE-EP on IL-6 upregulation was attenuated in the presence of lactoferrin, an inhibitor of LRP1. The prepared apoE-EP and serum triglyceride-rich lipoproteins showed significant affinity for LPS. However, these affinities appeared to be lower than expected based on the extent to which IL-6 upregulation was suppressed by pre-incubation of LPS with apoE-EP. Overall, these results indicate that LPS-induced inflammation may be regulated by 1) the LPS-neutralizing effect of apoE-LP, 2) anti-inflammatory effect of apoE, and 3) LRP1-mediated metabolic pathways.
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Affiliation(s)
- Shogo Akahane
- Department of Clinical Laboratory Investigation, 34808 Graduate School of Medicine, Shinshu University , Matsumoto 390-8621, Japan
| | - Hiroto Matsuura
- Department of Clinical Laboratory Investigation, 34808 Graduate School of Medicine, Shinshu University , Matsumoto 390-8621, Japan
| | - Takahiro Kaido
- Department of Clinical Laboratory Investigation, 34808 Graduate School of Medicine, Shinshu University , Matsumoto 390-8621, Japan
- Department of Laboratory Medicine, 34808 Shinshu University Hospital , Matsumoto 390-8621, Japan
| | - Yoko Usami
- Department of Laboratory Medicine, 34808 Shinshu University Hospital , Matsumoto 390-8621, Japan
| | - Nau Ishimine
- Department of Laboratory Medicine, 34808 Shinshu University Hospital , Matsumoto 390-8621, Japan
| | - Takeshi Uehara
- Department of Laboratory Medicine, 34808 Shinshu University Hospital , Matsumoto 390-8621, Japan
| | - Kazuyoshi Yamauchi
- Department of Clinical Laboratory Investigation, 34808 Graduate School of Medicine, Shinshu University , Matsumoto 390-8621, Japan
- Department of Biomedical Laboratory Sciences, 34808 School of Health Sciences, Shinshu University , 3-1-1 Asahi, Matsumoto 390-8621, Japan
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Su Q, Yang SP, Guo JP, Rong YR, Sun Y, Chai YR. Epigallocatechin-3-gallate ameliorates lipopolysaccharide-induced acute thymus involution in mice via AMPK/Sirt1 pathway. Microbiol Immunol 2024. [PMID: 38886542 DOI: 10.1111/1348-0421.13159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 05/08/2024] [Accepted: 05/27/2024] [Indexed: 06/20/2024]
Abstract
The thymus, a site to culture the naïve T lymphocytes, is susceptible to atrophy or involution due to aging, inflammation, and oxidation. Epigallocatechin-3-gallate (EGCG) has been proven to possess anti-inflammatory, antioxidant, and antitumor activity. Here, we investigate the effects of EGCG on thymic involution induced by lipopolysaccharide (LPS), an endotoxin derived from Gram-negative bacteria. The methodology included an in vivo experiment on female Kunming mice exposed to LPS and EGCG. Morphological assessment of thymic involution, immunohistochemical detection, and thymocyte subsets analysis by flow cytometry were further carried out to evaluate the potential role of EGCG on the thymus. As a result, we found that EGCG alleviated LPS-induced thymic atrophy, increased mitochondrial membrane potential and superoxide dismutase levels, and decreased malondialdehyde and reactive oxygen species levels. In addition, EGCG pre-supplement restored the ratio of thymocyte subsets, the expression of autoimmune regulator, sex-determining region Y-box 2, and Nanog homebox, and reduced the number of senescent cells and collagen fiber deposition. Western blotting results indicated that EGCG treatment elevated LPS-induced decrease in pAMPK, Sirt1 protein expression. Collectively, EGCG relieved thymus architecture and function damaged by LPS via regulation of AMPK/Sirt1 signaling pathway. Our findings may provide a new strategy on protection of thymus from involution caused by LPS by using EGCG. And EGCG might be considered as a potential agent for the prevention and treatment of thymic involution.
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Affiliation(s)
- Qing Su
- Department of Histology and Embryology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan, PR China
- The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, PR China
| | - Shu-Ping Yang
- Department of Histology and Embryology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan, PR China
- School of Medical Technology, Sanquan College of Xinxiang Medical University, Xinxiang, Henan, PR China
| | - Jun-Ping Guo
- Department of Histology and Embryology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan, PR China
| | - Yi-Ren Rong
- Department of Histology and Embryology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan, PR China
| | - Yun Sun
- Department of Histology and Embryology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan, PR China
| | - Yu-Rong Chai
- Department of Histology and Embryology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan, PR China
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14
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Liu M, Peng R, Tian C, Shi J, Ma J, Shi R, Qi X, Zhao R, Guan H. Effects of the gut microbiota and its metabolite short-chain fatty acids on endometriosis. Front Cell Infect Microbiol 2024; 14:1373004. [PMID: 38938880 PMCID: PMC11208329 DOI: 10.3389/fcimb.2024.1373004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 05/31/2024] [Indexed: 06/29/2024] Open
Abstract
In recent years, a growing body of research has confirmed that the gut microbiota plays a major role in the maintenance of human health and disease. A gut microbiota imbalance can lead to the development of many diseases, such as pregnancy complications, adverse pregnancy outcomes, polycystic ovary syndrome, endometriosis, and cancer. Short-chain fatty acids are metabolites of specific intestinal bacteria and are crucial for maintaining intestinal homeostasis and regulating metabolism and immunity. Endometriosis is the result of cell proliferation, escape from immune surveillance, and invasive metastasis. There is a strong correlation between the anti-proliferative and anti-inflammatory effects of short-chain fatty acids produced by gut microbes and the development of endometriosis. Given that the mechanism of action of gut microbiota and Short-chain fatty acids in endometriosis remain unclear, this paper aims to provide a comprehensive review of the complex interactions between intestinal flora, short-chain fatty acids and endometriosis. In addition, we explored potential microbial-based treatment strategies for endometriosis, providing new insights into the future development of diagnostic tests and prevention and treatment methods for endometriosis.
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Affiliation(s)
- Menghe Liu
- College of Pharmacy, Inner Mongolia Medical University, Hohhot, Inner Mongolia Autonomous Region, China
| | - Ru Peng
- Department of Obstetrics and Gynecology, Hohhot Maternal and Child Health Care Hospital, Hohhot, Inner Mongolia Autonomous Region, China
| | - Chunfang Tian
- Department of Oncology, Inner Mongolia Traditional Chinese Medicine Hospital, Hohhot, Inner Mongolia Autonomous Region, China
| | - Jianping Shi
- College of Traditional Chinese Medicine, Inner Mongolia Medical University, Hohhot, Inner Mongolia Autonomous Region, China
| | - Jiannan Ma
- College of Pharmacy, Inner Mongolia Medical University, Hohhot, Inner Mongolia Autonomous Region, China
| | - Ruiwen Shi
- College of Pharmacy, Inner Mongolia Medical University, Hohhot, Inner Mongolia Autonomous Region, China
| | - Xiao Qi
- College of Pharmacy, Inner Mongolia Medical University, Hohhot, Inner Mongolia Autonomous Region, China
| | - Rongwei Zhao
- Department of Obstetrics and Gynecology, Affiliated Hospital of Inner Mongolia Medical University, Hohhot, Inner Mongolia Autonomous Region, China
| | - Haibin Guan
- College of Pharmacy, Inner Mongolia Medical University, Hohhot, Inner Mongolia Autonomous Region, China
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15
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Kelly L, Jameson E. Bacteriophage cocktail shows no toxicity and improves the survival of Galleria mellonella infected with Klebsiella spp. J Virol 2024; 98:e0027224. [PMID: 38771043 PMCID: PMC11237459 DOI: 10.1128/jvi.00272-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 04/22/2024] [Indexed: 05/22/2024] Open
Abstract
Klebsiella spp. are causative agents of healthcare-associated infections in patients who are immunocompromised and use medical devices. The antibiotic resistance crisis has led to an increase in infections caused by these bacteria, which can develop into potentially life-threatening illnesses if not treated swiftly and effectively. Thus, new treatment options for Klebsiella are urgently required. Phage therapy can offer an alternative to ineffective antibiotic treatments for antibiotic-resistant bacteria infections. The aim of the present study was to produce a safe and effective phage cocktail treatment against Klebsiella pneumoniae and Klebsiella oxytoca, both in liquid in vitro culture and an in vivo Galleria mellonella infection model. The phage cocktail was significantly more effective at killing K. pneumoniae and K. oxytoca strains compared with monophage treatments. Preliminary phage cocktail safety was demonstrated through application in the in vivo G. mellonella model: where the phage cocktail induced no toxic side effects in G. mellonella. In addition, the phage cocktail significantly improved the survival of G. mellonella when administered as a prophylactic treatment, compared with controls. In conclusion, our phage cocktail was demonstrated to be safe and effective against Klebsiella spp. in the G. mellonella infection model. This provides a strong case for future treatment for Klebsiella infections, either as an alternative or adjunct to antibiotics.IMPORTANCEKlebsiella infections are a concern in individuals who are immunocompromised and are becoming increasingly difficult to treat with antibiotics due to their drug-resistant properties. Bacteriophage is one potential alternative therapy that could be used to tackle these infections. The present study describes the design of a non-toxic phage cocktail that improved the survival of Galleria mellonella infected with Klebsiella. This phage cocktail demonstrates potential for the safe and effective treatment of Klebsiella infections, as an adjunct or alternative to antibiotics.
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Affiliation(s)
- Lucy Kelly
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Eleanor Jameson
- School of Environmental and Natural Sciences, Bangor University, Gwynedd, United Kingdom
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16
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Dimba NR, Mzimela N, Khathi A. Improved Gut Health May Be a Potential Therapeutic Approach for Managing Prediabetes: A Literature Review. Biomedicines 2024; 12:1275. [PMID: 38927482 PMCID: PMC11201806 DOI: 10.3390/biomedicines12061275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 06/04/2024] [Accepted: 06/06/2024] [Indexed: 06/28/2024] Open
Abstract
Given the growing global threat and rising prevalence of type 2 diabetes mellitus (T2DM), addressing this metabolic disease is imperative. T2DM is preceded by prediabetes (PD), an intermediate hyperglycaemia that goes unnoticed for years in patients. Several studies have shown that gut microbial diversity and glucose homeostasis in PD or T2DM patients are affected. Therefore, this review aims to synthesize the existing literature to elucidate the association between high-calorie diets, intestinal permeability and their correlation with PD or T2DM. Moreover, it discusses the beneficial effects of different dietary interventions on improving gut health and glucose metabolism. The primary factor contributing to complications seen in PD or T2DM patients is the chronic consumption of high-calorie diets, which alters the gut microbial composition and increases the translocation of toxic substances from the intestinal lumen into the bloodstream. This causes an increase in inflammatory response that further impairs glucose regulation. Several dietary approaches or interventions have been implemented. However, only a few are currently in use and have shown promising results in improving beneficial microbiomes and glucose metabolism. Therefore, additional well-designed studies are still necessary to thoroughly investigate whether improving gut health using other types of dietary interventions can potentially manage or reverse PD, thereby preventing the onset of T2DM.
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Affiliation(s)
| | | | - Andile Khathi
- School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Westville 4000, South Africa; (N.R.D.); (N.M.)
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17
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Keener JE, Goh B, Yoo JS, Oh SF, Brodbelt JS. Top-Down Characterization of Bacterial Lipopolysaccharides and Lipooligosaccharides Using Activated-Electron Photodetachment Mass Spectrometry. Anal Chem 2024; 96:9151-9158. [PMID: 38758019 DOI: 10.1021/acs.analchem.4c00952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
Lipopolysaccharides (LPS) and lipooligosaccharides (LOS) are located in the outer membrane of Gram-negative bacteria and are comprised of three distinctive parts: lipid A, core oligosaccharide (OS), and O-antigen. The structure of each region influences bacterial stability, toxicity, and pathogenesis. Here, we highlight the use of targeted activated-electron photodetachment (a-EPD) tandem mass spectrometry to characterize LPS and LOS from two crucial players in the human gut microbiota, Escherichia coli Nissle and Bacteroides fragilis. a-EPD is a hybrid activation method that uses ultraviolet photoirradiation to generate charge-reduced radical ions followed by collisional activation to produce informative fragmentation patterns. We benchmark the a-EPD method for top-down characterization of triacyl LOS from E. coli R2, then focus on characterization of LPS from E. coli Nissle and B. fragilis. Notably, a-EPD affords extensive fragmentation throughout the backbone of the core OS and O-antigen regions of LPS from E. coli Nissle. This hybrid approach facilitated the elucidation of structural details for LPS from B. fragilis, revealing a putative hexuronic acid (HexA) conjugated to lipid A.
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Affiliation(s)
- James E Keener
- Department of Chemistry, University of Texas, Austin, Texas 78712, United States
| | - Byoungsook Goh
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, United States
| | - Ji-Sun Yoo
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, United States
| | - Sungwhan F Oh
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, United States
- Program in Immunology, Division of Medical Sciences, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas, Austin, Texas 78712, United States
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18
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Marrufo AM, Flores-Mireles AL. Macrophage fate: to kill or not to kill? Infect Immun 2024:e0047623. [PMID: 38829045 DOI: 10.1128/iai.00476-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024] Open
Abstract
Macrophages are dynamic innate immune cells that either reside in tissue, serving as sentinels, or recruited as monocytes from bone marrow into inflamed and infected tissue. In response to cues in the tissue microenvironment (TME), macrophages polarize on a continuum toward M1 or M2 with diverse roles in progression and resolution of disease. M1-like macrophages exhibit proinflammatory functions with antimicrobial and anti-tumorigenic activities, while M2-like macrophages have anti-inflammatory functions that generally resolve inflammatory responses and orchestrate a tissue healing process. Given these opposite phenotypes, proper spatiotemporal coordination of macrophage polarization in response to cues within the TME is critical to effectively resolve infectious disease and regulate wound healing. However, if this spatiotemporal coordination becomes disrupted due to persistent infection or dysregulated coagulation, macrophages' inappropriate response to these cues will result in the development of diseases with clinically unfavorable outcomes. Since plasticity and heterogeneity are hallmarks of macrophages, they are attractive targets for therapies to reprogram toward specific phenotypes that could resolve disease and favor clinical prognosis. In this review, we discuss how basic science studies have elucidated macrophage polarization mechanisms in TMEs during infections and inflammation, particularly coagulation. Therefore, understanding the dynamics of macrophage polarization within TMEs in diseases is important in further development of targeted therapies.
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Affiliation(s)
- Armando M Marrufo
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
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19
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Buchholz KR, Reichelt M, Johnson MC, Robinson SJ, Smith PA, Rutherford ST, Quinn JG. Potent activity of polymyxin B is associated with long-lived super-stoichiometric accumulation mediated by weak-affinity binding to lipid A. Nat Commun 2024; 15:4733. [PMID: 38830951 PMCID: PMC11148078 DOI: 10.1038/s41467-024-49200-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 05/23/2024] [Indexed: 06/05/2024] Open
Abstract
Polymyxins are gram-negative antibiotics that target lipid A, the conserved membrane anchor of lipopolysaccharide in the outer membrane. Despite their clinical importance, the molecular mechanisms underpinning polymyxin activity remain unresolved. Here, we use surface plasmon resonance to kinetically interrogate interactions between polymyxins and lipid A and derive a phenomenological model. Our analyses suggest a lipid A-catalyzed, three-state mechanism for polymyxins: transient binding, membrane insertion, and super-stoichiometric cluster accumulation with a long residence time. Accumulation also occurs for brevicidine, another lipid A-targeting antibacterial molecule. Lipid A modifications that impart polymyxin resistance and a non-bactericidal polymyxin derivative exhibit binding that does not evolve into long-lived species. We propose that transient binding to lipid A permeabilizes the outer membrane and cluster accumulation enables the bactericidal activity of polymyxins. These findings could establish a blueprint for discovery of lipid A-targeting antibiotics and provide a generalizable approach to study interactions with the gram-negative outer membrane.
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Affiliation(s)
- Kerry R Buchholz
- Department of Infectious Diseases, Genentech, Inc., South San Francisco, CA, USA.
| | - Mike Reichelt
- Department of Pathology, Genentech, Inc., South San Francisco, CA, USA
| | - Matthew C Johnson
- Department of Structural Biology, Genentech, Inc., South San Francisco, CA, USA
| | - Sarah J Robinson
- Department of Discovery Chemistry, Genentech, Inc., South San Francisco, CA, USA
| | - Peter A Smith
- Department of Infectious Diseases, Genentech, Inc., South San Francisco, CA, USA
- Revagenix, Inc., San Mateo, CA, USA
| | - Steven T Rutherford
- Department of Infectious Diseases, Genentech, Inc., South San Francisco, CA, USA.
| | - John G Quinn
- Department of Biochemical and Cellular Pharmacology, Genentech, Inc., South San Francisco, CA, USA.
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20
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Wang S, Yang Y, Jiang X, Zheng X, Wei Q, Dai W, Zhang X. Nurturing gut health: role of m6A RNA methylation in upholding the intestinal barrier. Cell Death Discov 2024; 10:271. [PMID: 38830900 PMCID: PMC11148167 DOI: 10.1038/s41420-024-02043-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 05/19/2024] [Accepted: 05/22/2024] [Indexed: 06/05/2024] Open
Abstract
The intestinal lumen acts as a critical interface connecting the external environment with the body's internal state. It's essential to prevent the passage of harmful antigens and bacteria while facilitating nutrient and water absorption. The intestinal barriers encompass microbial, mechanical, immunological, and chemical elements, working together to maintain intestinal balance. Numerous studies have associated m6A modification with intestinal homeostasis. This review comprehensively outlines potential mechanisms through which m6A modification could initiate, exacerbate, or sustain barrier damage from an intestinal perspective. The pivotal role of m6A modification in preserving intestinal equilibrium provides new insights, guiding the exploration of m6A modification as a target for optimizing preventive and therapeutic strategies for intestinal homeostasis.
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Affiliation(s)
| | - Yuzhong Yang
- Department of Pathology, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
| | - Xiaohan Jiang
- Department of Pathology, Liuzhou People's Hospital Affiliated to Guangxi Medical University, Liuzhou, Guangxi, China
| | - Xiang Zheng
- Department of Pathology, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
| | - Qiufang Wei
- Department of Pathology, Liuzhou People's Hospital Affiliated to Guangxi Medical University, Liuzhou, Guangxi, China
| | - Wenbin Dai
- Department of Pathology, Liuzhou People's Hospital Affiliated to Guangxi Medical University, Liuzhou, Guangxi, China.
| | - Xuemei Zhang
- Department of Pathology, Liuzhou People's Hospital Affiliated to Guangxi Medical University, Liuzhou, Guangxi, China.
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Biasetti L, Zervogiannis N, Shaw K, Trewhitt H, Serpell L, Bailey D, Wright E, Hall CN. Risk factors for severe COVID-19 disease increase SARS-CoV-2 infectivity of endothelial cells and pericytes. Open Biol 2024; 14:230349. [PMID: 38862017 DOI: 10.1098/rsob.230349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 04/15/2024] [Indexed: 06/13/2024] Open
Abstract
Coronavirus disease 2019 (COVID-19) was initially considered a primarily respiratory disease but is now known to affect other organs including the heart and brain. A major route by which COVID-19 impacts different organs is via the vascular system. We studied the impact of apolipoprotein E (APOE) genotype and inflammation on vascular infectivity by pseudo-typed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viruses in mouse and human cultured endothelial cells and pericytes. Possessing the APOE4 allele or having existing systemic inflammation is known to enhance the severity of COVID-19. Using targeted replacement human APOE3 and APOE4 mice and inflammation induced by bacterial lipopolysaccharide (LPS), we investigated infection by SARS-CoV-2. Here, we show that infectivity was higher in murine cerebrovascular pericytes compared to endothelial cells and higher in cultures expressing APOE4. Furthermore, increasing the inflammatory state of the cells by prior incubation with LPS increased infectivity into human and mouse pericytes and human endothelial cells. Our findings provide insights into the mechanisms underlying severe COVID-19 infection, highlighting how risk factors such as APOE4 genotype and prior inflammation may exacerbate disease severity by augmenting the virus's ability to infect vascular cells.
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Affiliation(s)
- Luca Biasetti
- Sussex Neuroscience, School of Psychology, University of Sussex , East Sussex BN1 9QG, UK
| | - Nikos Zervogiannis
- Sussex Neuroscience, School of Psychology, University of Sussex , East Sussex BN1 9QG, UK
| | - Kira Shaw
- Sussex Neuroscience, School of Psychology, University of Sussex , East Sussex BN1 9QG, UK
| | - Harry Trewhitt
- Sussex Neuroscience, School of Psychology, University of Sussex , East Sussex BN1 9QG, UK
| | - Louise Serpell
- Sussex Neuroscience, School of Life Sciences, University of Sussex , East Sussex BN1 9QG, UK
| | | | - Edward Wright
- Viral Pseudotype Unit, School of Life Sciences, University of Sussex , , East Sussex BN1 9QG, UK
| | - Catherine N Hall
- Sussex Neuroscience, School of Psychology, University of Sussex , East Sussex BN1 9QG, UK
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22
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Rai AK, Sawasato K, Bennett HC, Kozlova A, Sparagna GC, Bogdanov M, Mitchell AM. Genetic evidence for functional diversification of gram-negative intermembrane phospholipid transporters. PLoS Genet 2024; 20:e1011335. [PMID: 38913742 PMCID: PMC11226057 DOI: 10.1371/journal.pgen.1011335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 07/05/2024] [Accepted: 06/07/2024] [Indexed: 06/26/2024] Open
Abstract
The outer membrane of gram-negative bacteria is a barrier to chemical and physical stress. Phospholipid transport between the inner and outer membranes has been an area of intense investigation and, in E. coli K-12, it has recently been shown to be mediated by YhdP, TamB, and YdbH, which are suggested to provide hydrophobic channels for phospholipid diffusion, with YhdP and TamB playing the major roles. However, YhdP and TamB have different phenotypes suggesting distinct functions. It remains unclear whether these functions are related to phospholipid metabolism. We investigated a synthetic cold sensitivity caused by deletion of fadR, a transcriptional regulator controlling fatty acid degradation and unsaturated fatty acid production, and yhdP, but not by ΔtamB ΔfadR or ΔydbH ΔfadR. Deletion of tamB recuses the ΔyhdP ΔfadR cold sensitivity further demonstrating the phenotype is related to functional diversification between these genes. The ΔyhdP ΔfadR strain shows a greater increase in cardiolipin upon transfer to the non-permissive temperature and genetically lowering cardiolipin levels can suppress cold sensitivity. These data also reveal a qualitative difference between cardiolipin synthases in E. coli, as deletion of clsA and clsC suppresses cold sensitivity but deletion of clsB does not. Moreover, increased fatty acid saturation is necessary for cold sensitivity and lowering this level genetically or through supplementation of oleic acid suppresses the cold sensitivity of the ΔyhdP ΔfadR strain. Together, our data clearly demonstrate that the diversification of function between YhdP and TamB is related to phospholipid metabolism. Although indirect regulatory effects are possible, we favor the parsimonious hypothesis that YhdP and TamB have differential phospholipid-substrate transport preferences. Thus, our data provide a potential mechanism for independent control of the phospholipid composition of the inner and outer membranes in response to changing conditions based on regulation of abundance or activity of YhdP and TamB.
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Affiliation(s)
- Ashutosh K. Rai
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
| | - Katsuhiro Sawasato
- Department of Biochemistry and Molecular Biology, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Haley C. Bennett
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
| | - Anastasiia Kozlova
- Department of Biochemistry and Molecular Biology, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Genevieve C. Sparagna
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Mikhail Bogdanov
- Department of Biochemistry and Molecular Biology, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Angela M. Mitchell
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
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23
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Sölzer N, Brügemann K, Yin T, König S. Genetic evaluations and genome-wide association studies for specific digital dermatitis diagnoses in dairy cows considering genotype × housing system interactions. J Dairy Sci 2024; 107:3724-3737. [PMID: 38216046 DOI: 10.3168/jds.2023-24207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 12/06/2023] [Indexed: 01/14/2024]
Abstract
The present study aimed to use detailed phenotyping for the claw disorder digital dermatitis (DD) considering specific DD stages in 2 housing systems (conventional cubicle barns [CON] and compost-bedded pack barns [CBPB]) to infer possible genotype × housing system interactions. The DD stages included 2,980 observations for the 3 traits DD-sick, DD-acute, and DD-chronic from 1,311 Holstein-Friesian and 399 Fleckvieh-Simmental cows. Selection of the 5 CBPB and 5 CON herds was based on a specific protocol to achieve a high level of herd similarity with regard to climate, feeding, milking system, and location, but with pronounced housing-system differences. Five other farms had a "mixed system" with 2 subherds, one representing CBPB and the other one CON. The CBPB system was represented by 899 cows (1,530 observations), and 811 cows (1,450 observations) represented the CON system. The average disease prevalence was 20.47% for DD-sick, 13.88% for DD-acute, and 5.34% for DD-chronic, with a higher prevalence in CON than in CBPB. After quality control of 50K genotypes, 38,495 SNPs from 926 cows remained for the ongoing genomic analyses. Genetic parameters for DD-sick, DD-acute, and DD-chronic were estimated by applying single-step approaches for single-trait repeatability animal models considering the whole dataset, and separately for the CON and CBPB subsets. Genetic correlations between same DD traits from different housing systems, and between DD-sick, DD-chronic, and DD-acute, were estimated via bivariate animal models. Heritabilities based on the whole dataset were 0.16 for DD-sick, 0.14 for DD-acute, and 0.11 for DD-chronic. A slight increase of heritabilities and genetic variances was observed in CON compared with the "well-being" CBPB system, indicating a stronger genetic differentiation of diseases in a more challenging environment. Genetic correlations between same DD traits recorded in CON or CBPB were close to 0.80, disproving obvious genotype × housing system interactions. Genetic correlations among DD-sick, DD-acute and DD-chronic ranged from 0.58 to 0.81. SNP main effects and SNP × housing system interaction effects were estimated simultaneously via GWAS, considering only the phenotypes from genotyped cows. Ongoing annotations of potential candidate genes focused on chromosomal segments 100 kb upstream and downstream from the significantly associated candidate SNP. GWAS for main effects indicated heterogeneous Manhattan plots especially for DD-acute and DD-chronic, indicating particularities in disease pathogenesis. Nevertheless, a few shared annotated potential candidate genes, that is, METTL25, AFF3, PRKG1, and TENM4 for DD-sick and DD-acute, were identified. These genes have direct or indirect effects on disease resistance or immunology. For the SNP × housing system interaction, the annotated genes ASXL1 and NOL4L on BTA 13 were relevant for DD-sick and DD-acute. Overall, the very similar genetic parameters for the same traits in different environments and negligible genotype × housing system interactions indicate only minor effects on genetic evaluations for DD due to housing-system particularities.
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Affiliation(s)
- Niklas Sölzer
- Institute of Animal Breeding and Genetics, Justus-Liebig-University Gießen, 35390 Gießen, Germany
| | - Kerstin Brügemann
- Institute of Animal Breeding and Genetics, Justus-Liebig-University Gießen, 35390 Gießen, Germany
| | - Tong Yin
- Institute of Animal Breeding and Genetics, Justus-Liebig-University Gießen, 35390 Gießen, Germany
| | - Sven König
- Institute of Animal Breeding and Genetics, Justus-Liebig-University Gießen, 35390 Gießen, Germany.
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24
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Forster MC, Tekwani Movellan K, Najbauer EE, Becker S, Andreas LB. Magic-angle spinning NMR structure of Opa60 in lipid bilayers. J Struct Biol X 2024; 9:100098. [PMID: 39010882 PMCID: PMC11247266 DOI: 10.1016/j.yjsbx.2024.100098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/30/2024] [Accepted: 02/19/2024] [Indexed: 07/17/2024] Open
Abstract
Here we report the structure of Opa60 in lipid bilayers using proton-detected magic-angle spinning nuclear magnetic resonance (MAS NMR). Preparations including near-native oligosaccharide lipids reveal a consistent picture of a stable transmembrane beta barrel with a minor increase in the structured region as compared with the previously reported detergent structure. The large variable loops known to interact with host proteins could not be detected, confirming their dynamic nature even in a lipid bilayer environment. The structure provides a starting point for investigation of the functional role of Opa60 in gonococcal infection, which is understood to involve interaction with host proteins. At the same time, it demonstrates the recent advances in proton-detected methodology for membrane protein structure determination at atomic resolution by MAS NMR.
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Affiliation(s)
- Marcel C. Forster
- Department of NMR-based Structural Biology, Max-Planck-Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077 Göttingen, Germany
| | - Kumar Tekwani Movellan
- Department of NMR-based Structural Biology, Max-Planck-Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077 Göttingen, Germany
| | - Eszter E. Najbauer
- Department of NMR-based Structural Biology, Max-Planck-Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077 Göttingen, Germany
| | - Stefan Becker
- Department of NMR-based Structural Biology, Max-Planck-Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077 Göttingen, Germany
| | - Loren B. Andreas
- Department of NMR-based Structural Biology, Max-Planck-Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077 Göttingen, Germany
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25
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Alaman OAP, Pedrosa-Gerasmio IR, Koiwai K, Nozaki R, Kondo H, Hirono I. Molecular characterization of a short-chained pentraxin gene from kuruma shrimp Marsupenaeus japonicus hemocytes. FISH & SHELLFISH IMMUNOLOGY 2024; 149:109548. [PMID: 38588870 DOI: 10.1016/j.fsi.2024.109548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 04/02/2024] [Accepted: 04/05/2024] [Indexed: 04/10/2024]
Abstract
Pentraxins (PTXs) are a family of pattern recognition proteins (PRPs) that play a role in pathogen recognition during infection via pathogen-associated molecular patterns (PAMPs). Here, we characterized a short-chained pentraxin isolated from kuruma shrimp (Marsupenaeus japonicus) hemocytes (MjPTX). MjPTX contains the pentraxin signature HxCxS/TWxS (where x can be any amino acid), although the second conserved residue of this signature differed slightly (L instead of C). In the phylogenetic analysis, MjPTX clustered closely with predicted sequences from crustaceans (shrimp, lobster, and crayfish) displaying high sequence identities exceeding 52.67 %. In contrast, MjPTX showed minimal sequence identity when compared to functionally similar proteins in other animals, with sequence identities ranging from 20.42 % (mouse) to 28.14 % (horseshoe crab). MjPTX mRNA transcript levels increased significantly after artificial infection with Vibrio parahaemolyticus (48 h), White Spot Syndrome Virus (72 h) and Yellow Head Virus (24 and 48 h). Assays done in vitro revealed that recombinant MjPTX (rMjPTX) has an ability to agglutinate Gram-negative and Gram-positive bacteria and to bind microbial polysaccharides and bacterial suspensions in the presence of Ca2+. Taken together, our results suggest that MjPTX functions as a classical pattern recognition protein in the presence of calcium ions, that is capable of binding to specific moieties present on the surface of microorganisms and facilitating their clearance.
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Affiliation(s)
- Omar Adrianne P Alaman
- Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Tokyo, Japan; Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao, Iloilo, Philippines.
| | - Ivane R Pedrosa-Gerasmio
- Department of Marine Science, College of Science and Mathematics, Mindanao State University-Iligan Institute of Technology, Iligan City, Philippines
| | - Keichiro Koiwai
- Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Tokyo, Japan
| | - Reiko Nozaki
- Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Tokyo, Japan
| | - Hidehiro Kondo
- Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Tokyo, Japan
| | - Ikuo Hirono
- Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Tokyo, Japan
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26
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Zeng Y, Shen M, Liu S, Zhou X. Characterization and resistance mechanism of phage-resistant strains of Salmonella enteritidis. Poult Sci 2024; 103:103756. [PMID: 38652948 PMCID: PMC11063523 DOI: 10.1016/j.psj.2024.103756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 03/25/2024] [Accepted: 04/06/2024] [Indexed: 04/25/2024] Open
Abstract
In the face of the increasingly severe problem of antibiotic resistance, phage therapy is regarded as a highly potential alternative. Compared with traditional antimicrobial agents, a key research area of phage therapy is the study of phage-resistant mutant bacteria. To effectively monitor and prevent this resistance, it is crucial to conduct in-depth exploration of the mechanism behind phage resistance. In this study, a strain of Salmonella enteritidis (sm140) and the corresponding phage (Psm140) were isolated from chicken liver and sewage, respectively. Using the double-layer plate method, successfully screened out phage-resistant mutant strains. Whole-genome resequencing of 3 resistant strains found that the wbaP gene of all 3 strains had mutations at a specific position (1,118), with the base changing from G to A. This mutation causes the gene-encoded glycine to be replaced by aspartic acid. Subsequent studies found that the frequency of this gene mutation is extremely high, reaching 84%, and all mutations occur at the same position. To further explore the relationship between the wbaP gene and phage resistance, knockout strains and complement strains of the wbaP gene were constructed. The experimental results confirmed the association between the wbaP gene and phage resistance. At the same time, biological characteristics and virulence were evaluated for wild strains, resistant strains, knockout strains, and complement strains. It was found that mutations or deletions of the wbaP gene lead to a decrease in bacterial environmental adaptability and virulence. Through systematic research on the mechanism and biological characteristics of phage resistance, this study provides important references and guidance for the development of new phage therapies, promoting progress in the field of antimicrobial treatment. At the same time, the emergence of phage resistance due to wbaP gene mutations is reported for the first time in salmonella, providing a new perspective and ideas for further studying phage resistance mechanisms.
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Affiliation(s)
- Yukun Zeng
- College of Veterinary Medicine, Institute of Comparative Medicine, Yangzhou University, Yangzhou 225009, China
| | - Mangmang Shen
- College of Veterinary Medicine, Institute of Comparative Medicine, Yangzhou University, Yangzhou 225009, China
| | - Shenglong Liu
- College of Veterinary Medicine, Institute of Comparative Medicine, Yangzhou University, Yangzhou 225009, China
| | - Xin Zhou
- College of Veterinary Medicine, Institute of Comparative Medicine, Yangzhou University, Yangzhou 225009, China; Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou 225009, China.
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27
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Padhy I, Dwibedy SK, Mohapatra SS. A molecular overview of the polymyxin-LPS interaction in the context of its mode of action and resistance development. Microbiol Res 2024; 283:127679. [PMID: 38508087 DOI: 10.1016/j.micres.2024.127679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 03/03/2024] [Accepted: 03/06/2024] [Indexed: 03/22/2024]
Abstract
With the rising incidences of antimicrobial resistance (AMR) and the diminishing options of novel antimicrobial agents, it is paramount to decipher the molecular mechanisms of action and the emergence of resistance to the existing drugs. Polymyxin, a cationic antimicrobial lipopeptide, is used to treat infections by Gram-negative bacterial pathogens as a last option. Though polymyxins were identified almost seventy years back, their use has been restricted owing to toxicity issues in humans. However, their clinical use has been increasing in recent times resulting in the rise of polymyxin resistance. Moreover, the detection of "mobile colistin resistance (mcr)" genes in the environment and their spread across the globe have complicated the scenario. The mechanism of polymyxin action and the development of resistance is not thoroughly understood. Specifically, the polymyxin-bacterial lipopolysaccharide (LPS) interaction is a challenging area of investigation. The use of advanced biophysical techniques and improvement in molecular dynamics simulation approaches have furthered our understanding of this interaction, which will help develop polymyxin analogs with better bactericidal effects and lesser toxicity in the future. In this review, we have delved deeper into the mechanisms of polymyxin-LPS interactions, highlighting several models proposed, and the mechanisms of polymyxin resistance development in some of the most critical Gram-negative pathogens.
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Affiliation(s)
- Indira Padhy
- Molecular Microbiology Lab, Department of Biotechnology, Berhampur University, Bhanja Bihar, Berhampur 760007, Odisha, India
| | - Sambit K Dwibedy
- Molecular Microbiology Lab, Department of Biotechnology, Berhampur University, Bhanja Bihar, Berhampur 760007, Odisha, India
| | - Saswat S Mohapatra
- Molecular Microbiology Lab, Department of Biotechnology, Berhampur University, Bhanja Bihar, Berhampur 760007, Odisha, India.
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28
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Yuan Q, Liang R, Lv K, Shi X, Leng J, Liu Y, Xiao J, Zhang L, Zhao L. Structural characterization of a Chlorella heteropolysaccharide by analyzing its depolymerized product and finding an inducer of human dendritic cell maturation. Carbohydr Polym 2024; 333:122000. [PMID: 38494209 DOI: 10.1016/j.carbpol.2024.122000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 02/23/2024] [Accepted: 02/26/2024] [Indexed: 03/19/2024]
Abstract
Chlorella polysaccharides have been gaining increasing attention because of their high yield from dried Chlorella powder and their remarkable immunomodulatory activity. In this study, the major polysaccharide fraction, CPP-3a, in Chlorella pyrenoidosa, was isolated, and its detailed structure was investigated by analyzing the low-molecular-weight product prepared via free radical depolymerization. The results indicated that CPP-3a with a molecular weight of 195.2 kDa was formed by →2)-α-L-Araf-(1→, →2)-α-D-Rhap-(1→, →5)-α-L-Araf-(1→, →3)-β-D-Glcp-(1→, →4)-α-D-Glcp-(1→, →4)-α-D-GlcpA-(1→, →2,3)-α-D-Manp-(1→, →3,4)-α-D-Manp-(1→, →3,4)-β-D-Galp-(1→, →3,6)-β-D-Galp-(1→, and →2,3,6)-α-D-Galp-(1→ residues, branched at C2, C3, C4, or C6 of α/β-D-Galp and α-D-Manp, and terminated by α/β-L-Araf, α-L-Arap, α-D-Galp, and β-D-Glcp. Biological assays showed that CPP-3a significantly altered the dendritic morphology of immature dendritic cells (DCs). Enhanced CD80, CD86, and MHC I expression on the cell surface and decreased phagocytic ability indicated that CPP-3a could induce the maturation of DCs. Furthermore, CPP-3a-stimulated DCs not only stimulated the proliferation of allogeneic naïve CD4+ T cells and the secretion of IFN-γ, but also directly stimulated the activation and proliferation of CD8+ T cells through cross-antigen presentation. These findings indicate that CPP-3a can promote human DC maturation and T-cell stimulation and may be a novel DC maturation inducer with potential developmental value in DC immunotherapy.
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Affiliation(s)
- Qingxia Yuan
- Institute of Marine Drugs, Guangxi University of Chinese Medicine, Nanning 530200, China; Guangxi Key Laboratory of Marine Drugs, Guangxi University of Chinese Medicine, Nanning 530200, China
| | - Rongyi Liang
- Guangxi Key Laboratory of Translational Medicine for Treating High-Incidence Infectious Diseases with Integrative Medicine, Guangxi University of Chinese Medicine, Nanning 530200, China
| | - Kunling Lv
- Institute of Marine Drugs, Guangxi University of Chinese Medicine, Nanning 530200, China
| | - Xiaohuo Shi
- Instrumentation and Service Center for Molecular Sciences, Westlake University, Hangzhou 310024, China
| | - Jing Leng
- Guangxi Key Laboratory of Translational Medicine for Treating High-Incidence Infectious Diseases with Integrative Medicine, Guangxi University of Chinese Medicine, Nanning 530200, China
| | - Yonghong Liu
- Institute of Marine Drugs, Guangxi University of Chinese Medicine, Nanning 530200, China; Guangxi Key Laboratory of Marine Drugs, Guangxi University of Chinese Medicine, Nanning 530200, China
| | - Jian Xiao
- Guangxi Key Laboratory of Translational Medicine for Treating High-Incidence Infectious Diseases with Integrative Medicine, Guangxi University of Chinese Medicine, Nanning 530200, China.
| | - Lifeng Zhang
- Guangxi Key Laboratory of Translational Medicine for Treating High-Incidence Infectious Diseases with Integrative Medicine, Guangxi University of Chinese Medicine, Nanning 530200, China.
| | - Longyan Zhao
- Institute of Marine Drugs, Guangxi University of Chinese Medicine, Nanning 530200, China; Guangxi Key Laboratory of Marine Drugs, Guangxi University of Chinese Medicine, Nanning 530200, China.
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29
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Duve K, Petakh P, Kamyshnyi O. COVID-19-associated encephalopathy: connection between neuroinflammation and microbiota-gut-brain axis. Front Microbiol 2024; 15:1406874. [PMID: 38863751 PMCID: PMC11165208 DOI: 10.3389/fmicb.2024.1406874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 05/16/2024] [Indexed: 06/13/2024] Open
Abstract
While neurological complications of COVID-19, such as encephalopathy, are relatively rare, their potential significant impact on long-term morbidity is substantial, especially given the large number of infected patients. Two proposed hypotheses for the pathogenesis of this condition are hypoxia and the uncontrolled release of proinflammatory cytokines. The gut microbiota plays an important role in regulating immune homeostasis and overall gut health, including its effects on brain health through various pathways collectively termed the gut-brain axis. Recent studies have shown that COVID-19 patients exhibit gut dysbiosis, but how this dysbiosis can affect inflammation in the central nervous system (CNS) remains unclear. In this context, we discuss how dysbiosis could contribute to neuroinflammation and provide recent data on the features of neuroinflammation in COVID-19 patients.
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Affiliation(s)
- Khrystyna Duve
- Department of Neurology, I. Horbachevsky Ternopil National Medical University, Ternopil, Ukraine
| | - Pavlo Petakh
- Department of Biochemistry and Pharmacology, Uzhhorod National University, Uzhhorod, Ukraine
- Department of Microbiology, Virology, and Immunology, I. Horbachevsky Ternopil National Medical University, Ternopil, Ukraine
| | - Oleksandr Kamyshnyi
- Department of Biochemistry and Pharmacology, Uzhhorod National University, Uzhhorod, Ukraine
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30
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Zhang L, Tao M, Zhang H, Zhang S, Hou X, Zong C, Sun G, Feng S, Yan H, Lu Y, Yang X, Wei L, Zhang L. Lipopolysaccharide modification enhances the inhibitory effect of clodronate liposomes on hepatic fibrosis by depletion of macrophages and hepatic stellate cells. Chem Biol Interact 2024; 395:111015. [PMID: 38663797 DOI: 10.1016/j.cbi.2024.111015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 04/15/2024] [Accepted: 04/21/2024] [Indexed: 05/01/2024]
Abstract
Hepatic fibrosis is a complex chronic liver disease in which both macrophages and hepatic stellate cells (HSCs) play important roles. Many studies have shown that clodronate liposomes (CLD-lipos) effectively deplete macrophages. However, no liposomes have been developed that target both HSCs and macrophages. This study aimed to evaluate the therapeutic efficacy of lipopolysaccharide-coupled clodronate liposomes (LPS-CLD-lipos) and the effects of liposomes size on hepatic fibrosis. Three rat models of hepatic fibrosis were established in vivo; diethylnitrosamine (DEN), bile duct ligation (BDL), and carbon tetrachloride (CCl4). Hematoxylin and eosin staining and serological liver function indices were used to analyze pathological liver damage. Masson's trichrome and Sirius red staining were used to evaluate the effect of liposomes on liver collagen fibers. The hydroxyproline content in liver tissues was determined. In vitro cell counting kit-8 (CCK-8) and immunofluorescence assays were used to further explore the effects of LPS modification and liposomes size on the killing of macrophages and HSCs. Both in vitro and in vivo experiments showed that 200 nm LPS-CLD-lipos significantly inhibited hepatic fibrosis and the abnormal deposition of collagen fibers in the liver and improved the related indicators of liver function. Further results showed that 200 nm LPS-CLD-lipos increased the clearance of macrophages and induced apoptosis of hepatic stellate cells, significantly. The present study demonstrated that 200 nm LPS-CLD-lipos could significantly inhibit hepatic fibrosis and improve liver function-related indices and this study may provide novel ideas and directions for hepatic fibrosis treatment.
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Affiliation(s)
- Luyao Zhang
- School of Pharmacy, Anhui Medical University, Hefei, China; Department of Clinical Pharmacology, The Second Hospital of Anhui Medical University, Hefei, China; Clinical Research Unit, The First Affiliated Hospital of Naval Medical University, Shanghai, China
| | - Min Tao
- School of Pharmacy, Anhui Medical University, Hefei, China; Department of Clinical Pharmacology, The Second Hospital of Anhui Medical University, Hefei, China; Clinical Research Unit, The First Affiliated Hospital of Naval Medical University, Shanghai, China
| | - Hengyan Zhang
- Clinical Research Unit, The First Affiliated Hospital of Naval Medical University, Shanghai, China
| | - Shichao Zhang
- Department of Hepatic Surgery, The Eastern Hepatobiliary Surgery Hospital, Naval Medical University, Shanghai, China
| | - Xiaojuan Hou
- The National Center for Liver Cancer, Shanghai, China; Tumor Immunology and Gene Therapy Center, Third Affiliated Hospital of Naval Medical University, Shanghai, China
| | - Chen Zong
- The National Center for Liver Cancer, Shanghai, China; Tumor Immunology and Gene Therapy Center, Third Affiliated Hospital of Naval Medical University, Shanghai, China
| | - Gangqi Sun
- Molecular Pathology Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Shiyao Feng
- Department of Urology, Second Affiliated Hospital, Anhui Medical University, Hefei, China
| | - Haixin Yan
- Department of Urology, Second Affiliated Hospital, Anhui Medical University, Hefei, China
| | - Ying Lu
- Department of Pharmaceutical Sciences, School of Pharmacy, Naval Medical University, Shanghai, China
| | - Xue Yang
- The National Center for Liver Cancer, Shanghai, China; Tumor Immunology and Gene Therapy Center, Third Affiliated Hospital of Naval Medical University, Shanghai, China.
| | - Lixin Wei
- The National Center for Liver Cancer, Shanghai, China; Tumor Immunology and Gene Therapy Center, Third Affiliated Hospital of Naval Medical University, Shanghai, China.
| | - Li Zhang
- School of Pharmacy, Anhui Medical University, Hefei, China; Department of Clinical Pharmacology, The Second Hospital of Anhui Medical University, Hefei, China; Clinical Research Unit, The First Affiliated Hospital of Naval Medical University, Shanghai, China.
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31
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Wu T, Jiang J, Zhang H, Liu J, Ruan H. Transcending membrane barriers: advances in membrane engineering to enhance the production capacity of microbial cell factories. Microb Cell Fact 2024; 23:154. [PMID: 38796463 PMCID: PMC11128114 DOI: 10.1186/s12934-024-02436-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Accepted: 05/21/2024] [Indexed: 05/28/2024] Open
Abstract
Microbial cell factories serve as pivotal platforms for the production of high-value natural products, which tend to accumulate on the cell membrane due to their hydrophobic properties. However, the limited space of the cell membrane presents a bottleneck for the accumulation of these products. To enhance the production of intracellular natural products and alleviate the burden on the cell membrane caused by product accumulation, researchers have implemented various membrane engineering strategies. These strategies involve modifying the membrane components and structures of microbial cell factories to achieve efficient accumulation of target products. This review summarizes recent advances in the application of membrane engineering technologies in microbial cell factories, providing case studies involving Escherichia coli and yeast. Through these strategies, researchers have not only improved the tolerance of cells but also optimized intracellular storage space, significantly enhancing the production efficiency of natural products. This article aims to provide scientific evidence and references for further enhancing the efficiency of similar cell factories.
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Affiliation(s)
- Tao Wu
- Tianjin Key Laboratory of Food Science and Biotechnology, College of Biotechnology and Food Science, Tianjin University of Commerce, Tianjin, China.
| | - Jingjing Jiang
- Tianjin Key Laboratory of Food Science and Biotechnology, College of Biotechnology and Food Science, Tianjin University of Commerce, Tianjin, China
| | - Hongyang Zhang
- Tianjin Key Laboratory of Food Science and Biotechnology, College of Biotechnology and Food Science, Tianjin University of Commerce, Tianjin, China
| | - Jiazhi Liu
- Tianjin Key Laboratory of Food Science and Biotechnology, College of Biotechnology and Food Science, Tianjin University of Commerce, Tianjin, China
| | - Haihua Ruan
- Tianjin Key Laboratory of Food Science and Biotechnology, College of Biotechnology and Food Science, Tianjin University of Commerce, Tianjin, China.
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32
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Alamri MA, Prinsa, Kawsar SMA, Saha S. Exploring marine-derived bioactive compounds for dual inhibition of Pseudomonas aeruginosa LpxA and LpxD: integrated bioinformatics and cheminformatics approaches. Mol Divers 2024:10.1007/s11030-024-10888-8. [PMID: 38780832 DOI: 10.1007/s11030-024-10888-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 04/27/2024] [Indexed: 05/25/2024]
Abstract
Pseudomonas aeruginosa can cause serious nosocomial infections. Targeting the biosynthesis of Lipid A, a major structural domain of lipopolysaccharide (LPS) in P. aeruginosa has emerged as a valuable strategy for developing novel therapeutic agents. The biosynthesis of Lipid A involves the activation of homolog enzymes including LpxA and LpxD. LpxA enzyme facilitates the transfer of R-3-hydroxydecanoic fatty acid to uridine diphosphate N-acetylglucosamine in the first step. While LPxD is accountable in third step, wherein R-3-hydroxydodecanoate is transferred to the 2' amine of UDP-3-O-(3-hydroxydecanoyl) utilizing an ACP donor. The exploration of LpxA and LpxD has been largely neglected, as no specific small-molecule inhibitors have been identified, thus far, except for peptide inhibitors. Here, we report the identification of potential dual inhibitors of the lipid A biosynthesis pathway that target both the LpxA and LpxD enzymes as novel antibiotic agents. Among the virtually screened 32,000 marine bioactive compounds Oscillatoxin A, NCI60_041046, and LTS0192263 exhibited optimal docking interactions with LpxA and LpxD, respectively. MD simulation and MMPBSA data showcased stable interactions between selected marine products and LpxA/LpxD. FMO analysis showed that Oscillatoxin A and NCI60_041046 are the most chemically active molecules. MEP analysis data highlighted the possible electrophilic and nucleophilic distribution zones present in the structure. In addition, these bioactive molecules showed acceptable ADMET profiles. These data confirmed that Oscillatoxin A, NCI60_041046, and LTS0192263 could serve as seeds for the development of potential therapeutics to combat P. aeruginosa infection.
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Affiliation(s)
- Mubarak A Alamri
- Department of Pharmaceutical Chemistry, College of Pharmacy, Prince Sattam Bin Abdulaziz University, P.O. Box 173, 11942, Al-Kharj, Saudi Arabia
| | - Prinsa
- Siddhartha Institute of Pharmacy, Near IT-Park, Sahastradhara Road, Dehradun, 248001, Uttarakhand, India
| | - Sarkar M A Kawsar
- Laboratory of Carbohydrate and Nucleoside Chemistry, Department of Chemistry, Faculty of Science, University of Chittagong, Chittagong, 4331, Bangladesh
| | - Supriyo Saha
- Department of Pharmaceutical Chemistry, Uttaranchal Institute of Pharmaceutical Sciences, Uttaranchal University, Dehradun, 248001, Uttarakhand, India.
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Rai AK, Sawasato K, Bennett HC, Kozlova A, Sparagna GC, Bogdanov M, Mitchell AM. Genetic evidence for functional diversification of gram-negative intermembrane phospholipid transporters. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.06.21.545913. [PMID: 37745482 PMCID: PMC10515749 DOI: 10.1101/2023.06.21.545913] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
The outer membrane of Gram-negative bacteria is a barrier to chemical and physical stress. Phospholipid transport between the inner and outer membranes has been an area of intense investigation and, in E. coli K-12, it has recently been shown to be mediated by YhdP, TamB, and YdbH, which are suggested to provide hydrophobic channels for phospholipid diffusion, with YhdP and TamB playing the major roles. However, YhdP and TamB have different phenotypes suggesting distinct functions. We investigated these functions using synthetic cold sensitivity (at 30 °C) caused by deletion of yhdP and fadR, a transcriptional regulator controlling fatty acid degradation and unsaturated fatty acid production, but not by ΔtamB ΔfadR or ΔydbH ΔfadR,. Deletion of tamB suppresses the ΔyhdP ΔfadR cold sensitivity suggesting this phenotype is related to phospholipid transport. The ΔyhdP ΔfadR strain shows a greater increase in cardiolipin upon transfer to the non-permissive temperature and genetically lowering cardiolipin levels can suppress cold sensitivity. These data also reveal a qualitative difference between cardiolipin synthases in E. coli, as deletion of clsA and clsC suppresses cold sensitivity but deletion of clsB does not despite lower cardiolipin levels. In addition to increased cardiolipin, increased fatty acid saturation is necessary for cold sensitivity and lowering this level genetically or through supplementation of oleic acid suppresses the cold sensitivity of the ΔyhdP ΔfadR strain. Although indirect effects are possible, we favor the parsimonious hypothesis that YhdP and TamB have differential substrate transport preferences, most likely with YhdP preferentially transporting more saturated phospholipids and TamB preferentially transporting more unsaturated phospholipids. We envision cardiolipin contributing to this transport preference by sterically clogging TamB-mediated transport of saturated phospholipids. Thus, our data provide a potential mechanism for independent control of the phospholipid composition of the inner and outer membranes in response to changing conditions.
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Affiliation(s)
- Ashutosh K. Rai
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Katsuhiro Sawasato
- Department of Biochemistry and Molecular Biology, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Haley C. Bennett
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Anastasiia Kozlova
- Department of Biochemistry and Molecular Biology, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Genevieve C. Sparagna
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Mikhail Bogdanov
- Department of Biochemistry and Molecular Biology, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Angela M. Mitchell
- Department of Biology, Texas A&M University, College Station, Texas, USA
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Chisholm LO, Jaeger NM, Murawsky HE, Harms MJ. S100A9 interacts with a dynamic region on CD14 to activate Toll-like receptor 4. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.15.594416. [PMID: 38798518 PMCID: PMC11118535 DOI: 10.1101/2024.05.15.594416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
S100A9 is a Damage Associated Molecular Pattern (DAMP) that activates inflammatory pathways via Toll-like receptor 4 (TLR4). This activity plays important homeostatic roles in tissue repair, but can also contribute to inflammatory diseases. The mechanism of activation is unknown. Here, we follow up on a previous observation that the protein CD14 is an important co-receptor that enables S100A9 to activate TLR4. Using cell-based functional assays and a combination of mutations and pharmocological perturbations, we found that CD14 must be membrane bound to potentiate TLR4 activation by S100A9. Additionally, S100A9 is sensitive to inhibitors of pathways downstream of TLR4 internalization. Together, this suggests that S100A9 induces activity via CD14-dependent internalization of TLR4. We then used mutagenesis, structural modeling, and in vitro binding experiments to establish that S100A9 binds to CD14's N-terminus in a region that overlaps with, but is not identical to, the region where CD14 binds its canonical ligand, lipopolysaccharide (LPS). In molecular dynamics simulations, this region of the protein is dynamic, allowing it to reorganize to recognize both S100A9 (a soluble protein) and LPS (a small hydrophobic molecule). Our work is the first attempt at a molecular characterization of the S100A9/CD14 interaction, bringing us one step closer to unraveling the full mechanism by which S100A9 activates TLR4/MD-2.
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Karthikeyan D, Kumar S, Jayaprakash NS. A comprehensive review of recent developments in the gram-negative bacterial UDP-2,3-diacylglucosamine hydrolase (LpxH) enzyme. Int J Biol Macromol 2024; 267:131327. [PMID: 38574903 DOI: 10.1016/j.ijbiomac.2024.131327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 03/09/2024] [Accepted: 03/31/2024] [Indexed: 04/06/2024]
Abstract
The emergence of multidrug resistance has provided a great challenge to treat nosocomial infections, which have become a major health threat around the globe. Lipid A (an active endotoxin component), the final product of the Raetz lipid A metabolism pathway, is a membrane anchor of lipopolysaccharide (LPS) of the gram-negative bacterial outer membrane. It shields bacterial cells and serves as a protective barrier from antibiotics, thereby eliciting host response and making it difficult to destroy. UDP-2,3-diacylglucosamine pyrophosphate hydrolase (LpxH), a crucial peripheral membrane enzyme of the Raetz pathway, turned out to be the potential target to inhibit the production of Lipid A. This review provides a comprehensive compilation of information regarding the structural and functional aspects of LpxH, as well as its analogous LpxI and LpxG. In addition, apart from by providing a broader understanding of the enzyme-inhibitor mechanism, this review facilitates the development of novel drug candidates that can inhibit the pathogenicity of the lethal bacterium.
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Affiliation(s)
- Divyapriya Karthikeyan
- Centre for Bioseparation Technology, Vellore Institute of Technology, Vellore 632014, India
| | - Sanjit Kumar
- Department of Biotechnology, School of Interdisciplinary Education and Research, Guru Ghasidas Vishwavidyalaya, Bilaspur (A Central University), Chhattisgarh 495009, India
| | - N S Jayaprakash
- Centre for Bioseparation Technology, Vellore Institute of Technology, Vellore 632014, India.
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36
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Upton C, Healey J, Rothnie AJ, Goddard AD. Insights into membrane interactions and their therapeutic potential. Arch Biochem Biophys 2024; 755:109939. [PMID: 38387829 DOI: 10.1016/j.abb.2024.109939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 01/31/2024] [Accepted: 02/19/2024] [Indexed: 02/24/2024]
Abstract
Recent research into membrane interactions has uncovered a diverse range of therapeutic opportunities through the bioengineering of human and non-human macromolecules. Although the majority of this research is focussed on fundamental developments, emerging studies are showcasing promising new technologies to combat conditions such as cancer, Alzheimer's and inflammatory and immune-based disease, utilising the alteration of bacteriophage, adenovirus, bacterial toxins, type 6 secretion systems, annexins, mitochondrial antiviral signalling proteins and bacterial nano-syringes. To advance the field further, each of these opportunities need to be better understood, and the therapeutic models need to be further optimised. Here, we summarise the knowledge and insights into several membrane interactions and detail their current and potential uses therapeutically.
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Affiliation(s)
- Calum Upton
- School of Biosciences, Health & Life Science, Aston University, Birmingham, B4 7ET, UK
| | - Joseph Healey
- Nanosyrinx, The Venture Centre, University of Warwick Science Park, Coventry, CV4 7EZ, UK
| | - Alice J Rothnie
- School of Biosciences, Health & Life Science, Aston University, Birmingham, B4 7ET, UK
| | - Alan D Goddard
- School of Biosciences, Health & Life Science, Aston University, Birmingham, B4 7ET, UK.
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Wang H, Ishchenko A, Skudlarek J, Shen P, Dzhekieva L, Painter RE, Chen YT, Bukhtiyarova M, Leithead A, Tracy R, Babaoglu K, Bahnck-Teets C, Buevich A, Cabalu TD, Labroli M, Lange H, Lei Y, Li W, Liu J, Mann PA, Meng T, Mitchell HJ, Mulhearn J, Scapin G, Sha D, Shaw AW, Si Q, Tong L, Wu C, Wu Z, Xiao JC, Xu M, Zhang LK, McKenney D, Miller RR, Black TA, Cooke A, Balibar CJ, Klein DJ, Raheem I, Walker SS. Cerastecins inhibit membrane lipooligosaccharide transport in drug-resistant Acinetobacter baumannii. Nat Microbiol 2024; 9:1244-1255. [PMID: 38649414 DOI: 10.1038/s41564-024-01667-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 03/06/2024] [Indexed: 04/25/2024]
Abstract
Carbapenem-resistant Acinetobacter baumannii infections have limited treatment options. Synthesis, transport and placement of lipopolysaccharide or lipooligosaccharide (LOS) in the outer membrane of Gram-negative bacteria are important for bacterial virulence and survival. Here we describe the cerastecins, inhibitors of the A. baumannii transporter MsbA, an LOS flippase. These molecules are potent and bactericidal against A. baumannii, including clinical carbapenem-resistant Acinetobacter baumannii isolates. Using cryo-electron microscopy and biochemical analysis, we show that the cerastecins adopt a serpentine configuration in the central vault of the MsbA dimer, stalling the enzyme and uncoupling ATP hydrolysis from substrate flipping. A derivative with optimized potency and pharmacokinetic properties showed efficacy in murine models of bloodstream or pulmonary A. baumannii infection. While resistance development is inevitable, targeting a clinically unexploited mechanism avoids existing antibiotic resistance mechanisms. Although clinical validation of LOS transport remains undetermined, the cerastecins may open a path to narrow-spectrum treatment modalities for important nosocomial infections.
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Affiliation(s)
- Hao Wang
- Merck & Co., Inc., West Point, PA, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Ying Lei
- Merck & Co., Inc., West Point, PA, USA
| | - Wei Li
- Merck & Co., Inc., West Point, PA, USA
| | - Jian Liu
- Merck & Co., Inc., West Point, PA, USA
| | | | - Tao Meng
- Merck & Co., Inc., Rahway, NJ, USA
| | | | | | | | - Deyou Sha
- Merck & Co., Inc., West Point, PA, USA
| | | | - Qian Si
- Merck & Co., Inc., West Point, PA, USA
| | - Ling Tong
- Merck & Co., Inc., West Point, PA, USA
| | | | - Zhe Wu
- Merck & Co., Inc., West Point, PA, USA
| | | | - Min Xu
- Merck & Co., Inc., West Point, PA, USA
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38
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Shayan E, Maheri F, Aflaki F, Mousavi SE, Zarrindast MR, Fakhraei N, Rezayat Sorkhabadi SM, Shushtarian SMM. Synergistic effects of citicoline and silymarin nanomicelles in restraint stress-exposed mice. Behav Brain Res 2024; 464:114929. [PMID: 38428646 DOI: 10.1016/j.bbr.2024.114929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 02/12/2024] [Accepted: 02/27/2024] [Indexed: 03/03/2024]
Abstract
This study evaluated the effects of citicoline and silymarin nanomicelles (SMnm) in repeated restraint stress (RRS). METHOD Mice were exposed to RRS for four consecutive days, 2 hrs. daily. On day 5 of the study, SMnm (25 and 50 mg/kg, i.p.) and citicoline (25 and 75 mg/kg), and a combination of them (25 mg/kg, i.p.) were initiated. On day 18, anxiety-like behavior, behavioral despair, and exploratory behavior were evaluated. The prefrontal cortex (PFC) and the hippocampus were dissected measuring brain-derived neurotrophic factor (BDNF), cAMP response element-binding protein (CREB), and tumor necrosis factor-alpha (TNF-α) through Western Blot and ELISA, respectively. RESULTS In RR-exposed mice, anxiety-like behavior in the elevated plus maze (EPM) was enhanced by reductions in open arm time (OAT%) P < 0.001, and open arm entry (OAE%) P < 0.001. In the forced swimming test (FST), the immobility increased P < 0.001 while the swimming and climbing reduced P < 0.001. In the open field test (OFT), general motor activity was raised P < 0.05. Further, body weights reduced P < 0.001, and tissue BDNF and pCREB expressions decreased P < 0.001 while TNF-α increased P < 0.001. Conversely, SMnm, citicoline and their combination could reduce anxiety-like behavior P < 0.001. The combination group reduced the depressive-like behaviors P < 0.001. Moreover, body weights were restored P < 0.001. Besides, BDNF and pCREB expressions increased while TNF-α reduced, P < 0.001. CONCLUSION The combination synergistically improved emotion-like behaviors, alleviating the inflammation and upregulating the hippocampal BDNF-mediated CREB signaling pathway.
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Affiliation(s)
- Elham Shayan
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | - Fatemeh Maheri
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | - Fatemeh Aflaki
- Department of Biophysics and Biochemistry, Faculty of Advance Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Seyyedeh-Elaheh Mousavi
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences (TUMS), Tehran, Iran.
| | - Mohammad-Reza Zarrindast
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | - Nahid Fakhraei
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Seyed-Mohammad-Masoud Shushtarian
- Department of Biophysics and Biochemistry, Faculty of Advance Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
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Moreau F, Atamanyuk D, Blaukopf M, Barath M, Herczeg M, Xavier NM, Monbrun J, Airiau E, Henryon V, Leroy F, Floquet S, Bonnard D, Szabla R, Brown C, Junop MS, Kosma P, Gerusz V. Potentiating Activity of GmhA Inhibitors on Gram-Negative Bacteria. J Med Chem 2024; 67:6610-6623. [PMID: 38598312 PMCID: PMC11056994 DOI: 10.1021/acs.jmedchem.4c00037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 02/28/2024] [Accepted: 03/29/2024] [Indexed: 04/12/2024]
Abstract
Inhibition of the biosynthesis of bacterial heptoses opens novel perspectives for antimicrobial therapies. The enzyme GmhA responsible for the first committed biosynthetic step catalyzes the conversion of sedoheptulose 7-phosphate into d-glycero-d-manno-heptose 7-phosphate and harbors a Zn2+ ion in the active site. A series of phosphoryl- and phosphonyl-substituted derivatives featuring a hydroxamate moiety were designed and prepared from suitably protected ribose or hexose derivatives. High-resolution crystal structures of GmhA complexed to two N-formyl hydroxamate inhibitors confirmed the binding interactions to a central Zn2+ ion coordination site. Some of these compounds were found to be nanomolar inhibitors of GmhA. While devoid of HepG2 cytotoxicity and antibacterial activity of their own, they demonstrated in vitro lipopolysaccharide heptosylation inhibition in Enterobacteriaceae as well as the potentiation of erythromycin and rifampicin in a wild-type Escherichia coli strain. These inhibitors pave the way for a novel treatment of Gram-negative infections.
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Affiliation(s)
- François Moreau
- Mutabilis, 102 Avenue Gaston Roussel, Romainville 93230, France
| | | | - Markus Blaukopf
- Department
of Chemistry, University of Natural Resources
and Life Sciences, Muthgasse
18, Vienna A-1190, Austria
| | - Marek Barath
- Department
of Chemistry, University of Natural Resources
and Life Sciences, Muthgasse
18, Vienna A-1190, Austria
- Institute
of Chemistry, Center for Glycomics, Slovak
Academy of Sciences, Dúbravská cesta 9, Bratislava SK-845 38, Slovakia
| | - Mihály Herczeg
- Department
of Chemistry, University of Natural Resources
and Life Sciences, Muthgasse
18, Vienna A-1190, Austria
- Department
of Pharmaceutical Chemistry, University
of Debrecen, Debrecen 4032, Hungary
| | - Nuno M. Xavier
- Department
of Chemistry, University of Natural Resources
and Life Sciences, Muthgasse
18, Vienna A-1190, Austria
- Centro
de Química Estrutural, Institute of Molecular Sciences, Faculdade de Ciências, Universidade de Lisboa, Ed. C8, 5° Piso, Campo Grande, Lisboa 1749-016, Portugal
| | | | | | | | - Frédéric Leroy
- Carbosynth
Limited, 8&9 Old
Station Business Park, Compton, Berkshire RG20 6NE, U.K.
| | | | - Damien Bonnard
- Mutabilis, 102 Avenue Gaston Roussel, Romainville 93230, France
| | - Robert Szabla
- Department
of Biochemistry, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Chris Brown
- Department
of Biochemistry, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Murray S. Junop
- Department
of Biochemistry, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Paul Kosma
- Department
of Chemistry, University of Natural Resources
and Life Sciences, Muthgasse
18, Vienna A-1190, Austria
| | - Vincent Gerusz
- Mutabilis, 102 Avenue Gaston Roussel, Romainville 93230, France
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Zhang Y, Sun P, Li T, Li J, Ye J, Li X, Wu J, Lu Y, Zhu L, Wang H, Pan C. Efficient Production of Self-Assembled Bioconjugate Nanovaccines against Klebsiella pneumoniae O2 Serotype in Engineered Escherichia coli. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:728. [PMID: 38668222 PMCID: PMC11054253 DOI: 10.3390/nano14080728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 04/18/2024] [Accepted: 04/18/2024] [Indexed: 04/29/2024]
Abstract
Nanoparticles (NPs) have been surfacing as a pivotal platform for vaccine development. In our previous work, we developed a cholera toxin B subunit (CTB)-based self-assembled nanoparticle (CNP) and produced highly promising bioconjugate nanovaccines by loading bacterial polysaccharide (OPS) in vivo. In particular, the Klebsiella pneumoniae O2 serotype vaccine showcased a potent immune response and protection against infection. However, extremely low yields limited its further application. In this study, we prepared an efficient Klebsiella pneumoniae bioconjugate nanovaccine in Escherichia coli with a very high yield. By modifying the 33rd glycine (G) in the CNP to aspartate (D), we were able to observe a dramatically increased expression of glycoprotein. Subsequently, through a series of mutations, we determined that G33D was essential to increasing production. In addition, this increase only occurred in engineered E. coli but not in the natural host K. pneumoniae strain 355 (Kp355) expressing OPSKpO2. Next, T-cell epitopes were fused at the end of the CNP(G33D), and animal experiments showed that fusion of the M51 peptide induced high antibody titers, consistent with the levels of the original nanovaccine, CNP-OPSKpO2. Hence, we provide an effective approach for the high-yield production of K. pneumoniae bioconjugate nanovaccines and guidance for uncovering glycosylation mechanisms and refining glycosylation systems.
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Affiliation(s)
- Yan Zhang
- College of Food Science and Technology, Shanghai Ocean University, No. 999 Hucheng Huan Road, Lingang New City, Shanghai 201306, China
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, No. 20 Dongdajie Street, Fengtai District, Beijing 100071, China
| | - Peng Sun
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, No. 20 Dongdajie Street, Fengtai District, Beijing 100071, China
| | - Ting Li
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, No. 20 Dongdajie Street, Fengtai District, Beijing 100071, China
| | - Juntao Li
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, No. 20 Dongdajie Street, Fengtai District, Beijing 100071, China
| | - Jingqin Ye
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, No. 20 Dongdajie Street, Fengtai District, Beijing 100071, China
| | - Xiang Li
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, No. 20 Dongdajie Street, Fengtai District, Beijing 100071, China
| | - Jun Wu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, No. 20 Dongdajie Street, Fengtai District, Beijing 100071, China
| | - Ying Lu
- College of Food Science and Technology, Shanghai Ocean University, No. 999 Hucheng Huan Road, Lingang New City, Shanghai 201306, China
| | - Li Zhu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, No. 20 Dongdajie Street, Fengtai District, Beijing 100071, China
| | - Hengliang Wang
- College of Food Science and Technology, Shanghai Ocean University, No. 999 Hucheng Huan Road, Lingang New City, Shanghai 201306, China
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, No. 20 Dongdajie Street, Fengtai District, Beijing 100071, China
| | - Chao Pan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, No. 20 Dongdajie Street, Fengtai District, Beijing 100071, China
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Vieira-Neto A, Lean IJ, Santos JEP. Periparturient Mineral Metabolism: Implications to Health and Productivity. Animals (Basel) 2024; 14:1232. [PMID: 38672379 PMCID: PMC11047658 DOI: 10.3390/ani14081232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 04/02/2024] [Accepted: 04/08/2024] [Indexed: 04/28/2024] Open
Abstract
Mineral metabolism, in particular Ca, and to a lesser extent phosphorus (P) and magnesium (Mg), is altered with the onset of lactation because of extensive irreversible loss to synthesize colostrum and milk. The transient reduction in the concentration of Ca in blood, particularly when it lasts days, increases the risk of mineral-related disorders such as hypocalcemia and, to a lesser extent, hypophosphatemia. Although the incidence of clinical hypocalcemia can be reduced by prepartum dietary interventions, subclinical hypocalcemia remains prevalent, affecting up to 60% of the dairy cows in the first 3 d postpartum. More importantly, strong associations exist between hypocalcemia and increased susceptibility to other peripartum diseases and impaired reproductive performance. Mechanistic experiments have demonstrated the role of Ca on innate immune response in dairy cows, which presumably predisposes them to other diseases. Hypocalcemia is not related to inadequate Ca intake as prepartum diets marginal to deficient in Ca reduce the risk of the disease. Therefore, the understanding of how Ca homeostasis is regulated, in particular how calciotropic hormones such as parathyroid hormone and 1,25-dihydroxyvitamin D3, affect blood Ca concentrations, gastrointestinal Ca absorption, bone remodeling, and renal excretion of Ca become critical to develop novel strategies to prevent mineral imbalances either by nutritional or pharmacological interventions. A common method to reduce the risk of hypocalcemia is the manipulation of the prepartum dietary cation-anion difference. Feeding acidogenic diets not only improves Ca homeostasis and reduces hypocalcemia, but also reduces the risk of uterine diseases and improves productive performance. Feeding diets that induce a negative Ca balance in the last weeks of gestation also reduce the risk of clinical hypocalcemia, and recent work shows that the incorporation of mineral sequestering agents, presumably by reducing the absorption of P and Ca prepartum, increases blood Ca at calving, although benefits to production and health remain to be shown. Alternative strategies to minimize subclinical hypocalcemia with the use of vitamin D metabolites either fed prepartum or as a pharmacological agent administered immediately after calving have shown promising results in reducing hypocalcemia and altering immune cell function, which might prove efficacious to prevent diseases in early lactation. This review summarizes the current understanding of Ca homeostasis around parturition, the limited knowledge of the exact mechanisms for gastrointestinal Ca absorption in bovine, the implications of hypocalcemia on the health of dairy cows, and discusses the methods to minimize the risk of hypocalcemia and their impacts on productive performance and health in dairy cows.
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Affiliation(s)
- Achilles Vieira-Neto
- Department of Animal Sciences, University of Florida, Gainesville, FL 32611, USA;
| | - Ian J. Lean
- Scibus, Camden, NSW 2570, Australia;
- Faculty of Veterinary Science, The University of Sydney, Camden, NSW 2570, Australia
| | - José Eduardo P. Santos
- Department of Animal Sciences, University of Florida, Gainesville, FL 32611, USA;
- DH Barron Reproductive and Perinatal Biology Research Program, University of Florida, Gainesville, FL 32611, USA
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42
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Mettlach JA, Cian MB, Chakraborty M, Dalebroux ZD. Signaling through the Salmonella PbgA-LapB regulatory complex activates LpxC proteolysis and limits lipopolysaccharide biogenesis during stationary-phase growth. J Bacteriol 2024; 206:e0030823. [PMID: 38534107 PMCID: PMC11025326 DOI: 10.1128/jb.00308-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 02/27/2024] [Indexed: 03/28/2024] Open
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium) controls lipopolysaccharide (LPS) biosynthesis by regulating proteolysis of LpxC, the rate-limiting enzyme and target of preclinical antibiotics. PbgA/YejM/LapC regulates LpxC levels and controls outer membrane (OM) LPS composition at the log-to-stationary phase transition. Suppressor substitutions in LPS assembly protein B (LapB/YciM) rescue the LPS and OM integrity defects of pbgA-mutant S. Typhimurium. We hypothesized that PbgA regulates LpxC proteolysis by controlling LapB's ability to bind LpxC as a function of the growth phase. According to existing models, when nutrients are abundant, PbgA binds and restricts LapB from interacting with LpxC and FtsH, which limits LpxC proteolysis. However, when nutrients are limited, there is debate whether LapB dissociates from PbgA to bind LpxC and FtsH to enhance degradation. We sought to examine these models and investigate how the structure of LapB enables salmonellae to control LpxC proteolysis and LPS biosynthesis. Salmonellae increase LapB levels during the stationary phase to promote LpxC degradation, which limits lipid A-core production and increases their survival. The deletion of lapB, resulting in unregulated lipid A-core production and LpxC overabundance, leads to bacterial growth retardation. Tetratricopeptide repeats near the cytosol-inner membrane interface are sufficient for LapB to bind LpxC, and remarkably, LapB and PbgA interact in both growth phases, yet LpxC only associates with LapB in the stationary phase. Our findings support that PbgA-LapB exists as a constitutive complex in S. Typhimurium, which differentially binds LpxC to control LpxC proteolysis and limit lipid A-core biosynthesis in response to changes in the environment.IMPORTANCEAntimicrobial resistance has been a costly setback for human health and agriculture. Continued pursuit of new antibiotics and targets is imperative, and an improved understanding of existing ones is necessary. LpxC is an essential target of preclinical trial antibiotics that can eliminate multidrug-resistant Gram-negative bacterial infections. LapB is a natural LpxC inhibitor that targets LpxC for degradation and limits lipopolysaccharide production in Enterobacteriaceae. Contrary to some studies, findings herein support that LapB remains in complex instead of dissociating from its presumed negative regulator, PbgA/YejM/LapC, under conditions where LpxC proteolysis is enhanced. Advanced comprehension of this critical protein-lipid signaling network will lead to future development and refinement of small molecules that can specifically interfere.
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Affiliation(s)
- Joshua A. Mettlach
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Melina B. Cian
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Medha Chakraborty
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Zachary D. Dalebroux
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
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Hedley KE, Cuskelly A, Callister RJ, Horvat JC, Hodgson DM, Tadros MA. The medulla oblongata shows a sex-specific inflammatory response to systemic neonatal lipopolysaccharide. J Neuroimmunol 2024; 389:578316. [PMID: 38394966 DOI: 10.1016/j.jneuroim.2024.578316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 02/12/2024] [Accepted: 02/14/2024] [Indexed: 02/25/2024]
Abstract
Early life inflammation has been linked to long-term modulation of behavioural outcomes due to the central nervous system, but it is now becoming apparent it is also linked to dysfunction of visceral physiology. The medulla oblongata contains a number of nuclei critical for homeostasis, therefore we utilised the well-established model of neonatal lipopolysaccharide (LPS) exposure to examine the immediate and long-term impacts of systemic inflammation on the medulla oblongata. Wistar rats were injected with LPS or saline on postnatal days 3 and 5, with tissues collected on postnatal days 7 or 90 in order to assess expression of inflammatory mediators and microglial morphology in autonomic regions of the medulla oblongata. We observed a distinct sex-specific response of all measured inflammatory mediators at both ages, as well as significant neonatal sex differences in inflammatory mediators within saline groups. At both ages, microglial morphology had significant changes in branch length and soma size in a sex-specific manner in response to LPS exposure. This data not only highlights the strong sex-specific response of neonates to LPS administration, but also the significant life-long impact on the medulla oblongata and the potential altered control of visceral organs.
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Affiliation(s)
- Kateleen E Hedley
- School of Biomedical Sciences & Pharmacy, University of Newcastle, NSW, Australia; Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| | - Annalisa Cuskelly
- Hunter Medical Research Institute, New Lambton Heights, NSW, Australia; School of Psychological Sciences, University of Newcastle, NSW, Australia; School of Education, University of Newcastle, NSW, Australia
| | - Robert J Callister
- School of Biomedical Sciences & Pharmacy, University of Newcastle, NSW, Australia; Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| | - Jay C Horvat
- School of Biomedical Sciences & Pharmacy, University of Newcastle, NSW, Australia; Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| | - Deborah M Hodgson
- Hunter Medical Research Institute, New Lambton Heights, NSW, Australia; School of Psychological Sciences, University of Newcastle, NSW, Australia
| | - Melissa A Tadros
- School of Biomedical Sciences & Pharmacy, University of Newcastle, NSW, Australia; Hunter Medical Research Institute, New Lambton Heights, NSW, Australia.
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Mondal AH, Khare K, Saxena P, Debnath P, Mukhopadhyay K, Yadav D. A Review on Colistin Resistance: An Antibiotic of Last Resort. Microorganisms 2024; 12:772. [PMID: 38674716 PMCID: PMC11051878 DOI: 10.3390/microorganisms12040772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 04/04/2024] [Accepted: 04/08/2024] [Indexed: 04/28/2024] Open
Abstract
Antibiotic resistance has emerged as a significant global public health issue, driven by the rapid adaptation of microorganisms to commonly prescribed antibiotics. Colistin, previously regarded as a last-resort antibiotic for treating infections caused by Gram-negative bacteria, is increasingly becoming resistant due to chromosomal mutations and the acquisition of resistance genes carried by plasmids, particularly the mcr genes. The mobile colistin resistance gene (mcr-1) was first discovered in E. coli from China in 2016. Since that time, studies have reported different variants of mcr genes ranging from mcr-1 to mcr-10, mainly in Enterobacteriaceae from various parts of the world, which is a major concern for public health. The co-presence of colistin-resistant genes with other antibiotic resistance determinants further complicates treatment strategies and underscores the urgent need for enhanced surveillance and antimicrobial stewardship efforts. Therefore, understanding the mechanisms driving colistin resistance and monitoring its global prevalence are essential steps in addressing the growing threat of antimicrobial resistance and preserving the efficacy of existing antibiotics. This review underscores the critical role of colistin as a last-choice antibiotic, elucidates the mechanisms of colistin resistance and the dissemination of resistant genes, explores the global prevalence of mcr genes, and evaluates the current detection methods for colistin-resistant bacteria. The objective is to shed light on these key aspects with strategies for combating the growing threat of resistance to antibiotics.
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Affiliation(s)
- Aftab Hossain Mondal
- Department of Microbiology, Faculty of Allied Health Sciences, Shree Guru Gobind Singh Tricentenary University, Gurugram 122505, Haryana, India; (A.H.M.); (P.D.)
| | - Kriti Khare
- Antimicrobial Research Laboratory, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India; (K.K.); (P.S.); (K.M.)
| | - Prachika Saxena
- Antimicrobial Research Laboratory, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India; (K.K.); (P.S.); (K.M.)
| | - Parbati Debnath
- Department of Microbiology, Faculty of Allied Health Sciences, Shree Guru Gobind Singh Tricentenary University, Gurugram 122505, Haryana, India; (A.H.M.); (P.D.)
| | - Kasturi Mukhopadhyay
- Antimicrobial Research Laboratory, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India; (K.K.); (P.S.); (K.M.)
| | - Dhananjay Yadav
- Department of Life Science, Yeungnam University, Gyeongsan 712-749, Republic of Korea
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Lu H, Wang C, Lu W, Li X, Wang G, Dong W, Wang X, Chen H, Tan C. Antibacterial efficacy and mechanism of Cyprinus carpio chemokine-derived L-10 against multidrug-resistant Escherichia coli infections. Int J Antimicrob Agents 2024; 63:107104. [PMID: 38325720 DOI: 10.1016/j.ijantimicag.2024.107104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 01/02/2024] [Accepted: 01/29/2024] [Indexed: 02/09/2024]
Abstract
OBJECTIVES Antimicrobial resistance has raised concerns regarding untreatable infections and poses a growing threat to public health. Rational design of new AMPs is an ideal solution to this threat. METHODS In this study, we designed, modified, and synthesised an excellent AMP, L-10, based on the original sequence of the Cyprinus carpio chemokine. All experimental data were presented as the mean ± standard deviation (SD), and the two-tailed unpaired T-test method was used to analyze all data. RESULTS L-10 exhibited excellent antibacterial activity with negligible toxicity and improved the efficacy of a broad class of antibiotics against MDR Gram-negative pathogens, including tetracycline, meropenem, levofloxacin, and rifampin. Mechanistic studies have suggested that L-10 targets the bacterial membrane components, LPS and PG, to disrupt bacterial membrane integrity, thereby exerting antibacterial effects and enhancing the efficacy of antibiotics. Moreover, in animal infection models, L-10 significantly increased the survival rate of infected animals and effectively reduced the tissue bacterial load and inflammatory factor levels. In addition to its direct antibacterial activity, L-10 dramatically reduced pulmonary pathological alterations in a mouse model of endotoxemia and suppressed LPS-induced proinflammatory cytokines in vitro and in vivo. Lastly, L-10 was successfully expressed in Pichia pastoris and maintained antimicrobial activity against MDR Gram-negative pathogens in vivo and in vitro. CONCLUSION Collectively, these results reveal the potential of L-10 as an ideal candidate against MDR bacterial infections and provide new insights into the design, development, and clinical application of AMPs.
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Affiliation(s)
- Hao Lu
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China; Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Chenchen Wang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China; Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Wenjia Lu
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China; Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Xiaodan Li
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China; Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Gaoyan Wang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China; Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Wenqi Dong
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China; Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Xiangru Wang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China; Hubei Hongshan Laboratory, Wuhan, Hubei, China; Frontiers Science Center for Animal Breeding and Sustainable Production, Wuhan, Hubei, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
| | - Huanchun Chen
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China; Hubei Hongshan Laboratory, Wuhan, Hubei, China; Frontiers Science Center for Animal Breeding and Sustainable Production, Wuhan, Hubei, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
| | - Chen Tan
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China; Hubei Hongshan Laboratory, Wuhan, Hubei, China; Frontiers Science Center for Animal Breeding and Sustainable Production, Wuhan, Hubei, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China.
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Wang Z, Chen X, Yan L, Wang W, Zheng P, Mohammadreza A, Liu Q. Antimicrobial peptides in bone regeneration: mechanism and potential. Expert Opin Biol Ther 2024; 24:285-304. [PMID: 38567503 DOI: 10.1080/14712598.2024.2337239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 03/26/2024] [Indexed: 04/04/2024]
Abstract
INTRODUCTION Antimicrobial peptides (AMPs) are small-molecule peptides with a unique antimicrobial mechanism. Other notable biological activities of AMPs, including anti-inflammatory, angiogenesis, and bone formation effects, have recently received widespread attention. These remarkable bioactivities, combined with the unique antimicrobial mechanism of action of AMPs, have led to their increasingly important role in bone regeneration. AREAS COVERED In this review, on the one hand, we aimed to summarize information about the AMPs that are currently used for bone regeneration by reviewing published literature in the PubMed database. On the other hand, we also highlight some AMPs with potential roles in bone regeneration and their possible mechanisms of action. EXPERT OPINION The translation of AMPs to the clinic still faces many problems, but their unique antimicrobial mechanisms and other conspicuous biological activities suggest great potential. An in-depth understanding of the structure and mechanism of action of AMPs will help us to subsequently combine AMPs with different carrier systems and perform structural modifications to reduce toxicity and achieve stable release, which may be a key strategy for facilitating the translation of AMPs to the clinic.
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Affiliation(s)
- ZhiCheng Wang
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- School of Stomatology, Southern Medical University, Guangzhou, China
| | - XiaoMan Chen
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- School of Stomatology, Southern Medical University, Guangzhou, China
| | - Liang Yan
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- School of Stomatology, Southern Medical University, Guangzhou, China
| | - WenJie Wang
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- School of Stomatology, Southern Medical University, Guangzhou, China
| | - PeiJia Zheng
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- School of Stomatology, Southern Medical University, Guangzhou, China
| | - Atashbahar Mohammadreza
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- School of International Education, Southern Medical University, Guangzhou, China
| | - Qi Liu
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- School of Stomatology, Southern Medical University, Guangzhou, China
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Yoon Y, Song S. Structural Insights into the Lipopolysaccharide Transport (Lpt) System as a Novel Antibiotic Target. J Microbiol 2024; 62:261-275. [PMID: 38816673 DOI: 10.1007/s12275-024-00137-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 04/15/2024] [Accepted: 04/15/2024] [Indexed: 06/01/2024]
Abstract
Lipopolysaccharide (LPS) is a critical component of the extracellular leaflet within the bacterial outer membrane, forming an effective physical barrier against environmental threats in Gram-negative bacteria. After LPS is synthesized and matured in the bacterial cytoplasm and the inner membrane (IM), LPS is inserted into the outer membrane (OM) through the ATP-driven LPS transport (Lpt) pathway, which is an energy-intensive process. A trans-envelope complex that contains seven Lpt proteins (LptA-LptG) is crucial for extracting LPS from the IM and transporting it across the periplasm to the OM. The last step in LPS transport involves the mediation of the LptDE complex, facilitating the insertion of LPS into the outer leaflet of the OM. As the Lpt system plays an essential role in maintaining the impermeability of the OM via LPS decoration, the interactions between these interconnected subunits, which are meticulously regulated, may be potential targets for the development of new antibiotics to combat multidrug-resistant Gram-negative bacteria. In this review, we aimed to provide an overview of current research concerning the structural interactions within the Lpt system and their implications to clarify the function and regulation of LPS transport in the overall process of OM biogenesis. Additionally, we explored studies on the development of therapeutic inhibitors of LPS transport, the factors that limit success, and future prospects.
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Affiliation(s)
- Yurim Yoon
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology, Daejeon, 34114, Republic of Korea
| | - Saemee Song
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology, Daejeon, 34114, Republic of Korea.
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Zhang Y, Huang K, Duan J, Zhao R, Yang L. Gut microbiota connects the brain and the heart: potential mechanisms and clinical implications. Psychopharmacology (Berl) 2024; 241:637-651. [PMID: 38407637 DOI: 10.1007/s00213-024-06552-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 02/04/2024] [Indexed: 02/27/2024]
Abstract
Nowadays, high morbidity and mortality of cardiovascular diseases (CVDs) and high comorbidity rate of neuropsychiatric disorders contribute to global burden of health and economics. Consequently, a discipline concerning abnormal connections between the brain and the heart and the resulting disease states, known as psychocardiology, has garnered interest among researchers. However, identifying a common pathway that physicians can modulate remains a challenge. Gut microbiota, a constituent part of the human intestinal ecosystem, is likely involved in mutual mechanism CVDs and neuropsychiatric disorder share, which could be a potential target of interventions in psychocardiology. This review aimed to discuss complex interactions from the perspectives of microbial and intestinal dysfunction, behavioral factors, and pathophysiological changes and to present possible approaches to regulating gut microbiota, both of which are future directions in psychocardiology.
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Affiliation(s)
- Yi Zhang
- Department of Cardiology, The Third Affiliated Hospital of Soochow University, Changzhou, 213003, China
| | - Kai Huang
- Department of Cardiology, The Third Affiliated Hospital of Soochow University, Changzhou, 213003, China
| | - Jiahao Duan
- Department of Cardiology, The Third Affiliated Hospital of Soochow University, Changzhou, 213003, China
| | - Rong Zhao
- Department of Cardiology, The Third Affiliated Hospital of Soochow University, Changzhou, 213003, China.
| | - Ling Yang
- Department of Cardiology, The Third Affiliated Hospital of Soochow University, Changzhou, 213003, China.
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Majumder S, Das S, Li P, Yang N, Dellario H, Sui H, Guan Z, Sun W. Pneumonic Plague Protection Induced by a Monophosphoryl Lipid A Decorated Yersinia Outer-Membrane-Vesicle Vaccine. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2307066. [PMID: 38009518 PMCID: PMC11009084 DOI: 10.1002/smll.202307066] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 10/19/2023] [Indexed: 11/29/2023]
Abstract
A new Yersinia pseudotuberculosis mutant strain, YptbS46, carrying the lpxE insertion and pmrF-J deletion is constructed and shown to exclusively produce monophosphoryl lipid A (MPLA) having adjuvant properties. Outer membrane vesicles (OMVs) isolated from YptbS46 harboring an lcrV expression plasmid, pSMV13, are designated OMV46-LcrV, which contained MPLA and high amounts of LcrV (Low Calcium response V) and displayed low activation of Toll-like receptor 4 (TLR4). Intramuscular prime-boost immunization with 30 µg of of OMV46-LcrV exhibited substantially reduced reactogenicity than the parent OMV44-LcrV and conferred complete protection to mice against a high-dose of respiratory Y. pestis challenge. OMV46-LcrV immunization induced robust adaptive responses in both lung mucosal and systemic compartments and orchestrated innate immunity in the lung, which are correlated with rapid bacterial clearance and unremarkable lung damage during Y. pestis challenge. Additionally, OMV46-LcrV immunization conferred long-term protection. Moreover, immunization with reduced doses of OMV46-LcrV exhibited further lower reactogenicity and still provided great protection against pneumonic plague. The studies strongly demonstrate the feasibility of OMV46-LcrV as a new type of plague vaccine candidate.
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Affiliation(s)
- Saugata Majumder
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, 12208, USA
| | - Shreya Das
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, 12208, USA
| | - Peng Li
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, 12208, USA
| | - Nicole Yang
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, 12208, USA
| | - Hazel Dellario
- Wadsworth Center, New York State Department of Health, Albany, NY, 12237, USA
| | - Haixin Sui
- Wadsworth Center, New York State Department of Health, Albany, NY, 12237, USA
| | - Ziqiang Guan
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Wei Sun
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, 12208, USA
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Brown GC, Heneka MT. The endotoxin hypothesis of Alzheimer's disease. Mol Neurodegener 2024; 19:30. [PMID: 38561809 PMCID: PMC10983749 DOI: 10.1186/s13024-024-00722-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 03/18/2024] [Indexed: 04/04/2024] Open
Abstract
Lipopolysaccharide (LPS) constitutes much of the surface of Gram-negative bacteria, and if LPS enters the human body or brain can induce inflammation and act as an endotoxin. We outline the hypothesis here that LPS may contribute to the pathophysiology of Alzheimer's disease (AD) via peripheral infections or gut dysfunction elevating LPS levels in blood and brain, which promotes: amyloid pathology, tau pathology and microglial activation, contributing to the neurodegeneration of AD. The evidence supporting this hypothesis includes: i) blood and brain levels of LPS are elevated in AD patients, ii) AD risk factors increase LPS levels or response, iii) LPS induces Aβ expression, aggregation, inflammation and neurotoxicity, iv) LPS induces TAU phosphorylation, aggregation and spreading, v) LPS induces microglial priming, activation and neurotoxicity, and vi) blood LPS induces loss of synapses, neurons and memory in AD mouse models, and cognitive dysfunction in humans. However, to test the hypothesis, it is necessary to test whether reducing blood LPS reduces AD risk or progression. If the LPS endotoxin hypothesis is correct, then treatments might include: reducing infections, changing gut microbiome, reducing leaky gut, decreasing blood LPS, or blocking LPS response.
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Affiliation(s)
- Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom.
| | - Michael T Heneka
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Belvaux, Luxembourg
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