1
|
Feng Y, Sun Q, Liu P, Fan W, Fan B. Antibacterial Property and Mechanisms of Au@Ag Core-Shell Nanoparticles with Near-Infrared Absorption Against E. faecalis Infection of Dentin. Int J Nanomedicine 2024; 19:6981-6997. [PMID: 39005961 PMCID: PMC11246666 DOI: 10.2147/ijn.s468649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Accepted: 06/21/2024] [Indexed: 07/16/2024] Open
Abstract
Background Enterococcus faecalis (E. faecalis) is one of the main pathogens responsible for refractory root canal infections in the teeth and shows resistance against various antibacterial managements. Effective control of E. faecalis infection is a prerequisite for successful treatment of refractory apical periodontitis. This study aimed to analyze the antibacterial activity and mechanisms of Au@Ag nanoparticles (NPs) combined with photothermal therapy (PTT) against the original and Ag+-resistant E. faecalis. Methods Au@AgNPs with optimal shell thicknesses were synthesized and characterized. The antibacterial activity of Au@AgNPs with PTT against the original or Ag+-resistant E. faecalis was evaluated, and the antibiofilm activity was tested on E. faecalis biofilm on the dentin of teeth. The potential antibacterial mechanisms of Au@AgNPs combined with PTT against E. faecalis have also been studied. Moreover, its influence on dentin microhardness and cytotoxicity was assessed. Results This study revealed that Au@AgNPs combined with PTT showed enhanced antibacterial and antibiofilm effects, no negative effects on dentin microhardness, and low cytotoxicity toward human periodontal ligament cells (hPDLCs). Moreover, Au@AgNPs combined with PTT effectively inhibited the growth of Ag+-resistant E. faecalis. Its antibacterial effects may be exerted through the release of silver ions (Ag+), destruction of the cell membrane, production of reactive oxygen species (ROS) and inhibition of adenosine triphosphate (ATP) production. Hyperthermia generated by Au@AgNPs with PTT reduced membrane fluidity and enhanced Ag+ sensitivity by downregulating fabF expression. The upregulated expression of heat shock genes demonstrated that the Ag+ released from Au@AgNPs compromised the heat adaptation of E. faecalis. Conclusion PTT significantly enhanced Ag+ sensitivity of the original and Ag+-resistant E. faecalis. Au@AgNPs combined with PTT may have the potential to be developed as a new antibacterial agent to control E. faecalis infections in teeth.
Collapse
Affiliation(s)
- Yaxu Feng
- The State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, People’s Republic of China
| | - Qing Sun
- The State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, People’s Republic of China
| | - Pei Liu
- The State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, People’s Republic of China
| | - Wei Fan
- The State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, People’s Republic of China
| | - Bing Fan
- The State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, People’s Republic of China
| |
Collapse
|
2
|
Bohl V, Mogk A. When the going gets tough, the tough get going-Novel bacterial AAA+ disaggregases provide extreme heat resistance. Environ Microbiol 2024; 26:e16677. [PMID: 39039821 DOI: 10.1111/1462-2920.16677] [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: 04/29/2024] [Accepted: 07/05/2024] [Indexed: 07/24/2024]
Abstract
Heat stress can lead to protein misfolding and aggregation, potentially causing cell death due to the loss of essential proteins. Bacteria, being particularly exposed to environmental stress, are equipped with disaggregases that rescue these aggregated proteins. The bacterial Hsp70 chaperone DnaK and the ATPase associated with diverse cellular activities protein ClpB form the canonical disaggregase in bacteria. While this combination operates effectively during physiological heat stress, it is ineffective against massive aggregation caused by temperature-based sterilization protocols used in the food industry and clinics. This leaves bacteria unprotected against these thermal processes. However, bacteria that can withstand extreme, man-made stress conditions have emerged. These bacteria possess novel ATPase associated with diverse cellular activities disaggregases, ClpG and ClpL, which are key players in extreme heat resistance. These disaggregases, present in selected Gram-negative or Gram-positive bacteria, respectively, function superiorly by exhibiting increased thermal stability and enhanced threading power compared to DnaK/ClpB. This enables ClpG and ClpL to operate at extreme temperatures and process large and tight protein aggregates, thereby contributing to heat resistance. The genes for ClpG and ClpL are often encoded on mobile genomic islands or conjugative plasmids, allowing for their rapid spread among bacteria via horizontal gene transfer. This threatens the efficiency of sterilization protocols. In this review, we describe the various bacterial disaggregases identified to date, characterizing their commonalities and the specific features that enable these novel disaggregases to provide stress protection against extreme stress conditions.
Collapse
Affiliation(s)
- Valentin Bohl
- Faculty of Biosciences, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| | - Axel Mogk
- Faculty of Biosciences, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| |
Collapse
|
3
|
Liu J, Wang J, Zhang Z, Bai Q, Pan X, Chen R, Yao H, Yu Y, Ma J. Streptococcus suis Deploys Multiple ATP-Dependent Proteases for Heat Stress Adaptation. J Basic Microbiol 2024:e2400030. [PMID: 39031597 DOI: 10.1002/jobm.202400030] [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: 01/20/2024] [Revised: 04/24/2024] [Accepted: 05/19/2024] [Indexed: 07/22/2024]
Abstract
Streptococcus suis is an important zoonotic pathogen, causing cytokine storms of Streptococcal toxic shock-like syndrome amongst humans after a wound infection into the bloodstream. To overcome the challenges of fever and leukocyte recruitment, invasive S. suis must deploy multiple stress responses forming a network and utilize proteases to degrade short-lived regulatory and misfolded proteins induced by adverse stresses, thereby adapting and evading host immune responses. In this study, we found that S. suis encodes multiple ATP-dependent proteases, including single-chain FtsH and double-subunit Clp protease complexes ClpAP, ClpBP, ClpCP, and ClpXP, which were activated as the fever of infected mice in vivo. The expression of genes ftsH, clpA/B/C, and clpP, but not clpX, were significantly upregulated in S. suis in response to heat stress, while were not changed notably under the treatments with several other stresses, including oxidative, acidic, and cold stimulation. FtsH and ClpP were required for S. suis survival within host blood under heat stress in vitro and in vivo. Deletion of ftsH or clpP attenuated the tolerance of S. suis to heat, oxidative and acidic stresses, and significantly impaired the bacterial survival within macrophages. Further analysis identified that repressor CtsR directly binds and controls the clpA/B/C and clpP operons and is relieved by heat stress. In summary, the deployments of multiple ATP-dependent proteases form a flexible heat stress response network that appears to allow S. suis to fine-tune the degradation or refolding of the misfolded proteins to maintain cellular homeostasis and optimal survival during infection.
Collapse
Affiliation(s)
- Jianan Liu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing Agricultural University, Nanjing, China
| | - Jianzhong Wang
- Suzhou Xiangcheng Fisheries Technology Promotion Center, Suzhou Animal Disease Prevention and Control Center, Suzhou, China
| | - Zhen Zhang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing Agricultural University, Nanjing, China
| | - Qiankun Bai
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing Agricultural University, Nanjing, China
| | - Xinming Pan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing Agricultural University, Nanjing, China
| | - Rong Chen
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing Agricultural University, Nanjing, China
| | - Huochun Yao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing Agricultural University, Nanjing, China
| | - Yong Yu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing Agricultural University, Nanjing, China
| | - Jiale Ma
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing Agricultural University, Nanjing, China
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
| |
Collapse
|
4
|
Yang L, Wu Z, Ma TY, Zeng H, Chen M, Zhang YA, Zhou Y. Identification of ClpB, a molecular chaperone involved in the stress tolerance and virulence of Streptococcus agalactiae. Vet Res 2024; 55:60. [PMID: 38750480 PMCID: PMC11094935 DOI: 10.1186/s13567-024-01318-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Accepted: 03/06/2024] [Indexed: 05/19/2024] Open
Abstract
Bacterial ClpB is an ATP-dependent disaggregate that belongs to the Hsp100/Clp family and facilitates bacterial survival under hostile environmental conditions. Streptococcus agalactiae, which is regarded as the major bacterial pathogen of farmed Nile tilapia (Oreochromis niloticus), is known to cause high mortality and large economic losses. Here, we report a ClpB homologue of S. agalactiae and explore its functionality. S. agalactiae with a clpB deletion mutant (∆clpB) exhibited defective tolerance against heat and acidic stress, without affecting growth or morphology under optimal conditions. Moreover, the ΔclpB mutant exhibited reduced intracellular survival in RAW264.7 cells, diminished adherence to the brain cells of tilapia, increased sensitivity to leukocytes from the head kidney of tilapia and whole blood killing, and reduced mortality and bacterial loads in a tilapia infection assay. Furthermore, the reduced virulence of the ∆clpB mutant was investigated by transcriptome analysis, which revealed that deletion of clpB altered the expression levels of multiple genes that contribute to the stress response as well as certain metabolic pathways. Collectively, our findings demonstrated that ClpB, a molecular chaperone, plays critical roles in heat and acid stress resistance and virulence in S. agalactiae. This finding provides an enhanced understanding of the functionality of this ClpB homologue in gram-positive bacteria and the survival strategy of S. agalactiae against immune clearance during infection.
Collapse
Affiliation(s)
- Lan Yang
- National Key Laboratory of Agricultural Microbiology; Hubei Hongshan Laboratory; Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education; Shenzhen Institute of Nutrition and Health, College of Fisheries, Huazhong Agricultural University, Wuhan, 430000, China
| | - Zhihao Wu
- National Key Laboratory of Agricultural Microbiology; Hubei Hongshan Laboratory; Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education; Shenzhen Institute of Nutrition and Health, College of Fisheries, Huazhong Agricultural University, Wuhan, 430000, China
| | - Tian-Yu Ma
- National Key Laboratory of Agricultural Microbiology; Hubei Hongshan Laboratory; Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education; Shenzhen Institute of Nutrition and Health, College of Fisheries, Huazhong Agricultural University, Wuhan, 430000, China
| | - Hui Zeng
- National Key Laboratory of Agricultural Microbiology; Hubei Hongshan Laboratory; Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education; Shenzhen Institute of Nutrition and Health, College of Fisheries, Huazhong Agricultural University, Wuhan, 430000, China
| | - Ming Chen
- National Key Laboratory of Agricultural Microbiology; Hubei Hongshan Laboratory; Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education; Shenzhen Institute of Nutrition and Health, College of Fisheries, Huazhong Agricultural University, Wuhan, 430000, China
| | - Yong-An Zhang
- National Key Laboratory of Agricultural Microbiology; Hubei Hongshan Laboratory; Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education; Shenzhen Institute of Nutrition and Health, College of Fisheries, Huazhong Agricultural University, Wuhan, 430000, China.
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510000, China.
| | - Yang Zhou
- National Key Laboratory of Agricultural Microbiology; Hubei Hongshan Laboratory; Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education; Shenzhen Institute of Nutrition and Health, College of Fisheries, Huazhong Agricultural University, Wuhan, 430000, China.
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510000, China.
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture,, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518000, China.
| |
Collapse
|
5
|
The role of uspE in virulence and biofilm formation by Histophilus somni. Vet Microbiol 2021; 263:109267. [PMID: 34739965 DOI: 10.1016/j.vetmic.2021.109267] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 10/20/2021] [Indexed: 01/18/2023]
Abstract
UspE is a global regulator in Escherichia coli. To study the function of Histophilus somni uspE, strain 2336::TnuspE was identified from a bank of mutants generated with EZ::Tn5™<KAN-2> Tnp Transposome™ that were biofilm deficient. The 2336::TnuspE mutant was highly attenuated in mice, the electrophoretic profile of its lipooligosaccharide (LOS) indicated the LOS was truncated, and the mutant was significantly more serum-sensitive compared to the wildtype strain. In addition to forming a deficient biofilm, exopolysaccharide (EPS) production was also compromised, but the electrophoretic profile of outer membrane proteins was not altered. RNA sequence analysis revealed that the transcription levels of some stress response chaperones, transport proteins, and a large number of ribosomal protein genes in 2336::TnuspE were significantly differentially regulated compared to strain 2336. Therefore, uspE may differentially function in direct and indirect expression of H. somni genes, but its attenuation may be linked to poor biofilm formation and rapid clearance of the bacteria resulting from a compromised LOS structure. Our results support that uspE is a global stress regulatory gene in H. somni.
Collapse
|
6
|
Hsp100 Molecular Chaperone ClpB and Its Role in Virulence of Bacterial Pathogens. Int J Mol Sci 2021; 22:ijms22105319. [PMID: 34070174 PMCID: PMC8158500 DOI: 10.3390/ijms22105319] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/14/2021] [Accepted: 05/15/2021] [Indexed: 01/05/2023] Open
Abstract
This review focuses on the molecular chaperone ClpB that belongs to the Hsp100/Clp subfamily of the AAA+ ATPases and its biological function in selected bacterial pathogens, causing a variety of human infectious diseases, including zoonoses. It has been established that ClpB disaggregates and reactivates aggregated cellular proteins. It has been postulated that ClpB’s protein disaggregation activity supports the survival of pathogenic bacteria under host-induced stresses (e.g., high temperature and oxidative stress), which allows them to rapidly adapt to the human host and establish infection. Interestingly, ClpB may also perform other functions in pathogenic bacteria, which are required for their virulence. Since ClpB is not found in human cells, this chaperone emerges as an attractive target for novel antimicrobial therapies in combating bacterial infections.
Collapse
|
7
|
Alam A, Bröms JE, Kumar R, Sjöstedt A. The Role of ClpB in Bacterial Stress Responses and Virulence. Front Mol Biosci 2021; 8:668910. [PMID: 33968993 PMCID: PMC8100447 DOI: 10.3389/fmolb.2021.668910] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 04/06/2021] [Indexed: 02/04/2023] Open
Abstract
Bacterial survival within a mammalian host is contingent upon sensing environmental perturbations and initiating an appropriate counter-response. To achieve this, sophisticated molecular machineries are used, where bacterial chaperone systems play key roles. The chaperones are a prerequisite for bacterial survival during normal physiological conditions as well as under stressful situations, e.g., infection or inflammation. Specific stress factors include, but are not limited to, high temperature, osmolarity, pH, reactive oxidative species, or bactericidal molecules. ClpB, a member of class 1 AAA+ proteins, is a key chaperone that via its disaggregase activity plays a crucial role for bacterial survival under various forms of stress, in particular heat shock. Recently, it has been reported that ClpB also regulates secretion of bacterial effector molecules related to type VI secretion systems. In this review, the roles of ClpB in stress responses and the mechanisms by which it promotes survival of pathogenic bacteria are discussed.
Collapse
Affiliation(s)
- Athar Alam
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Clinical Microbiology, Umeå University, Umeå, Sweden
| | - Jeanette E Bröms
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Clinical Microbiology, Umeå University, Umeå, Sweden
| | - Rajender Kumar
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Clinical Microbiology, Umeå University, Umeå, Sweden
| | - Anders Sjöstedt
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Clinical Microbiology, Umeå University, Umeå, Sweden
| |
Collapse
|
8
|
Feng Y, Wang H, Lu HE, Yi L, Hong LI. Effects of ClpP protease on biofilm formation of Enterococcus faecalis. J Appl Oral Sci 2021; 29:e20200733. [PMID: 33656065 PMCID: PMC7934281 DOI: 10.1590/1678-7757-2020-0733] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 11/25/2020] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVES Enterococcus faecalis (E. faecalis), one of the main pathogens responsible for refractory periapical periodontitis and nosocomial infections, exhibits markedly higher pathogenicity in biofilms. Studies have shown that caseinolytic protease P (ClpP) is involved in biofilm formation. However, to date, few studies have investigated the role of ClpP in the survival of E. faecalis, and in enhancing biofilm formation. Therefore, we investigated the role of ClpP in the formation of E. faecalis biofilms. METHODOLOGY In our study, we used homologous recombination to construct clpP deleted and clpP complement strains of E. faecalis ATCC 29212. A viable colony counting method was used to analyze the growth patterns of E. faecalis. Crystal violet staining (CV) and confocal scanning laser microscopy (CLSM) were used to characterize biofilm mass formation and scanning electron microscopy (SEM) was used to observe the biofilm microstructure. Data was statistically analyzed via Student's t-test or one-way analysis of variance (ANOVA). RESULTS The results exhibited altered growth patterns for the clpP deletion strains and depleted polysaccharide matrix, resulting in reduced biofilm formation capacity compared to the standard strains. Moreover, ClpP was observed to increase biofilm formation in E. faecalis. CONCLUSION Our study shows that ClpP can increase biofilm formation in E. faecalis and emphasizes the importance of ClpP as a potential target against E. faecalis.
Collapse
Affiliation(s)
- Ying Feng
- Department of Endodontics, School of Stomatology, Capital Medical University
| | - Hongyuan Wang
- Department of Endodontics, School of Stomatology, Capital Medical University
| | - H E Lu
- Affiliated Stomatology Hospital of Guangzhou Medical University
| | - Liu Yi
- Laboratory of Tissue Regeneration and Immunology and Department of Periodontics, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, School of Stomatology, Capital Medical University
| | - L I Hong
- Department of Endodontics, School of Stomatology, Capital Medical University
| |
Collapse
|
9
|
Glaza P, Ranaweera CB, Shiva S, Roy A, Geisbrecht BV, Schoenen FJ, Zolkiewski M. Repurposing p97 inhibitors for chemical modulation of the bacterial ClpB-DnaK bichaperone system. J Biol Chem 2021; 296:100079. [PMID: 33187983 PMCID: PMC7948422 DOI: 10.1074/jbc.ra120.015413] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 10/31/2020] [Accepted: 11/13/2020] [Indexed: 01/18/2023] Open
Abstract
The ClpB-DnaK bichaperone system reactivates aggregated cellular proteins and is essential for survival of bacteria, fungi, protozoa, and plants under stress. AAA+ ATPase ClpB is a promising target for the development of antimicrobials because a loss of its activity is detrimental for survival of many pathogens and no apparent ClpB orthologs are found in metazoans. We investigated ClpB activity in the presence of several compounds that were previously described as inhibitor leads for the human AAA+ ATPase p97, an antitumor target. We discovered that N2,N4-dibenzylquinazoline-2,4-diamine (DBeQ), the least potent among the tested p97 inhibitors, binds to ClpB with a Kd∼60 μM and inhibits the casein-activated, but not the basal, ATPase activity of ClpB with an IC50∼5 μM. The remaining p97 ligands, which displayed a higher affinity toward p97, did not affect the ClpB ATPase. DBeQ also interacted with DnaK with a Kd∼100 μM and did not affect the DnaK ATPase but inhibited the DnaK chaperone activity in vitro. DBeQ inhibited the reactivation of aggregated proteins by the ClpB-DnaK bichaperone system in vitro with an IC50∼5 μM and suppressed the growth of cultured Escherichia coli. The DBeQ-induced loss of E. coli proliferation was exacerbated by heat shock but was nearly eliminated in a ClpB-deficient E. coli strain, which demonstrates a significant selectivity of DBeQ toward ClpB in cells. Our results provide chemical validation of ClpB as a target for developing novel antimicrobials. We identified DBeQ as a promising lead compound for structural optimization aimed at selective targeting of ClpB and/or DnaK.
Collapse
Affiliation(s)
- Przemyslaw Glaza
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas, USA
| | - Chathurange B Ranaweera
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas, USA
| | - Sunitha Shiva
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas, USA
| | - Anuradha Roy
- High Throughput Screening Laboratory, University of Kansas, Lawrence, Kansas, USA; Lead Development and Optimization Shared Resource, University of Kansas Cancer Center, Kansas City, Kansas, USA
| | - Brian V Geisbrecht
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas, USA
| | - Frank J Schoenen
- Lead Development and Optimization Shared Resource, University of Kansas Cancer Center, Kansas City, Kansas, USA; Higuchi Biosciences Center, University of Kansas, Lawrence, Kansas, USA
| | - Michal Zolkiewski
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas, USA.
| |
Collapse
|
10
|
Tripathi P, Singh LK, Kumari S, Hakiem OR, Batra JK. ClpB is an essential stress regulator of Mycobacterium tuberculosis and endows survival advantage to dormant bacilli. Int J Med Microbiol 2020; 310:151402. [PMID: 32014406 DOI: 10.1016/j.ijmm.2020.151402] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 12/03/2019] [Accepted: 01/20/2020] [Indexed: 12/13/2022] Open
Abstract
The ability to tolerate multiple host derived stresses, resist eradication and persist within the infected individuals is central to the pathogenicity of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB). Mycobacterial survival is contingent upon sensing environmental perturbations and initiating a fitting response to counter them. Therefore, understanding of molecular mechanisms underlying stress tolerance and sensing in Mtb is critical for devising strategies for TB control. Our study aims to delineate the role of ClpB, a heat shock protein of Hsp100 family, in the general stress response and persistence mechanisms of Mtb. We demonstrate that Mtb requires ClpB to survive under stressful conditions. Additionally, we show that ClpB is necessary for the bacteria to persist in latency-like conditions such as prolonged hypoxia and nutrient-starvation. The disruption of ClpB results in aberrant cellular morphology, impaired biofilm formation and reduced infectivity of Mtb ex vivo. Our study also reports an alternative role of ClpB as a chaperokine which elicits inflammatory response in host. We conclude that ClpB is essential for Mtb to survive within macrophages, and plays a crucial part in the maintenance of dormant Mtb bacilli in latent state. The absence of ClpB in human genome makes it an attractive choice as drug target for TB.
Collapse
Affiliation(s)
- Prajna Tripathi
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Lalit K Singh
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Sujata Kumari
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Owais R Hakiem
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Janendra K Batra
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India; Department of Biochemistry, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi 110062, India.
| |
Collapse
|
11
|
Lazaretti WY, Dos Santos EL, da-Conceição Silva JL, Kadowaki MK, Gandra RF, Maller A, Simão RDCG. Upregulation of the clpB gene in response to heat shock and beta-lactam antibiotics in Acinetobacter baumannii. Mol Biol Rep 2019; 47:1499-1505. [PMID: 31786767 DOI: 10.1007/s11033-019-05209-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 11/26/2019] [Indexed: 01/18/2023]
Abstract
The role of the clpB gene encoding HSP/chaperone ClpB was evaluated in the multiresistant antibiotic cells of Acinetobacter baumannii (RS4 strain) under stress-induced heat shock and different beta-lactams. The expression of the clpB gene was assessed by qPCR during heat shock at 45 °C and subinhibitory concentrations of ampicillin (30 μg mL-1), amoxicillin + sulbactam (8/12 μg mL-1), cefepime (30 μg mL-1), sulfamethoxazole + trimethoprim (120/8 μg mL-1) and meropenem (18 μg mL-1). The results indicated a transient increase in clpB transcription in all treatments except cefepime. Both in the presence of ampicillin and amoxicillin/sulbactam for 20 min, the mRNA-clpB synthesis was 1.4 times higher than that of the control at time zero. Surprisingly, the mRNA-clpB levels were more than 30-fold higher after 10 min of incubation with meropenem and more than eightfold higher in the presence of trimethoprim/sulfamethoxazole. In addition, western blot assays showed that the RS4 strain treated with meropenem showed a marked increase in ClpB protein expression. Our data indicate that during exposure to beta-lactams, A. baumannii adjusts the transcription levels of the clpB mRNA and protein to respond to stress, suggesting that the chaperone may act as a key cellular component in the presence of antibiotics in this bacterium.
Collapse
Affiliation(s)
- Waleska Yana Lazaretti
- Laboratório de Bioquímica Molecular, Centro de Ciências Médicas e Farmacêuticas, Universidade Estadual do Oeste do Paraná, UNIOESTE, Rua Universitária, 2069, Cascavel, PR, 85814-110, Brazil
| | - Elaine Luzia Dos Santos
- Laboratório de Bioquímica Molecular, Centro de Ciências Médicas e Farmacêuticas, Universidade Estadual do Oeste do Paraná, UNIOESTE, Rua Universitária, 2069, Cascavel, PR, 85814-110, Brazil
| | - José Luis da-Conceição Silva
- Laboratório de Bioquímica Molecular, Centro de Ciências Médicas e Farmacêuticas, Universidade Estadual do Oeste do Paraná, UNIOESTE, Rua Universitária, 2069, Cascavel, PR, 85814-110, Brazil
| | - Marina Kimiko Kadowaki
- Laboratório de Bioquímica Molecular, Centro de Ciências Médicas e Farmacêuticas, Universidade Estadual do Oeste do Paraná, UNIOESTE, Rua Universitária, 2069, Cascavel, PR, 85814-110, Brazil
| | - Rinaldo Ferreira Gandra
- Laboratório de Micologia Clínica, Hospital Universitário do Oeste do Paraná, Universidade Estadual do Oeste do Paraná, UNIOESTE, Cascavel, PR, Brazil
| | - Alexandre Maller
- Laboratório de Bioquímica Molecular, Centro de Ciências Médicas e Farmacêuticas, Universidade Estadual do Oeste do Paraná, UNIOESTE, Rua Universitária, 2069, Cascavel, PR, 85814-110, Brazil
| | - Rita de Cássia Garcia Simão
- Laboratório de Bioquímica Molecular, Centro de Ciências Médicas e Farmacêuticas, Universidade Estadual do Oeste do Paraná, UNIOESTE, Rua Universitária, 2069, Cascavel, PR, 85814-110, Brazil.
| |
Collapse
|
12
|
Adaptation to Adversity: the Intermingling of Stress Tolerance and Pathogenesis in Enterococci. Microbiol Mol Biol Rev 2019; 83:83/3/e00008-19. [PMID: 31315902 DOI: 10.1128/mmbr.00008-19] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Enterococcus is a diverse and rugged genus colonizing the gastrointestinal tract of humans and numerous hosts across the animal kingdom. Enterococci are also a leading cause of multidrug-resistant hospital-acquired infections. In each of these settings, enterococci must contend with changing biophysical landscapes and innate immune responses in order to successfully colonize and transit between hosts. Therefore, it appears that the intrinsic durability that evolved to make enterococci optimally competitive in the host gastrointestinal tract also ideally positioned them to persist in hospitals, despite disinfection protocols, and acquire new antibiotic resistances from other microbes. Here, we discuss the molecular mechanisms and regulation employed by enterococci to tolerate diverse stressors and highlight the role of stress tolerance in the biology of this medically relevant genus.
Collapse
|
13
|
Tripathi P, Parijat P, Patel VK, Batra JK. The amino-terminal domain of Mycobacterium tuberculosis ClpB protein plays a crucial role in its substrate disaggregation activity. FEBS Open Bio 2018; 8:1669-1690. [PMID: 30338218 PMCID: PMC6168691 DOI: 10.1002/2211-5463.12509] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 08/03/2018] [Accepted: 08/08/2018] [Indexed: 01/09/2023] Open
Abstract
Mycobacterium tuberculosis (Mtb) is known to persist in extremely hostile environments within host macrophages. The ability to withstand such proteotoxic stress comes from its highly conserved molecular chaperone machinery. ClpB, a unique member of the AAA+ family of chaperones, is responsible for resolving aggregates in Mtb and many other bacterial pathogens. Mtb produces two isoforms of ClpB, a full length and an N-terminally truncated form (ClpB∆N), with the latter arising from an internal translation initiation site. It is not clear why this internal start site is conserved and what role the N-terminal domain (NTD) of Mtb ClpB plays in its function. In the current study, we functionally characterized and compared the two isoforms of Mtb ClpB. We found the NTD to be dispensable for oligomerization, ATPase activity and prevention of aggregation activity of ClpB. Both ClpB and ClpB∆N were found to be capable of resolubilizing protein aggregates. However, the efficiency of ClpB∆N at resolubilizing higher order aggregates was significantly lower than that of ClpB. Further, ClpB∆N exhibited reduced affinity for substrates as compared to ClpB. We also demonstrated that the surface of the NTD of Mtb ClpB has a hydrophobic groove that contains four hydrophobic residues: L97, L101, F140 and V141. These residues act as initial contacts for the substrate and are crucial for stable interaction between ClpB and highly aggregated substrates.
Collapse
Affiliation(s)
| | - Priyanka Parijat
- National Institute of ImmunologyNew DelhiIndia
- Present address:
Randall Division of Cell and Molecular BiophysicsKing's College LondonUK
| | | | - Janendra K. Batra
- National Institute of ImmunologyNew DelhiIndia
- Department of BiochemistrySchool of Chemical and Life SciencesJamia HamdardNew DelhiIndia
| |
Collapse
|
14
|
Stand-alone ClpG disaggregase confers superior heat tolerance to bacteria. Proc Natl Acad Sci U S A 2017; 115:E273-E282. [PMID: 29263094 DOI: 10.1073/pnas.1712051115] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
AAA+ disaggregases solubilize aggregated proteins and confer heat tolerance to cells. Their disaggregation activities crucially depend on partner proteins, which target the AAA+ disaggregases to protein aggregates while concurrently stimulating their ATPase activities. Here, we report on two potent ClpG disaggregase homologs acquired through horizontal gene transfer by the species Pseudomonas aeruginosa and subsequently abundant P. aeruginosa clone C. ClpG exhibits high, stand-alone disaggregation potential without involving any partner cooperation. Specific molecular features, including high basal ATPase activity, a unique aggregate binding domain, and almost exclusive expression in stationary phase distinguish ClpG from other AAA+ disaggregases. Consequently, ClpG largely contributes to heat tolerance of P. aeruginosa primarily in stationary phase and boosts heat resistance 100-fold when expressed in Escherichia coli This qualifies ClpG as a potential persistence and virulence factor in P. aeruginosa.
Collapse
|
15
|
Kuczynska-Wisnik D, Cheng C, Ganta RR, Zolkiewski M. Protein aggregation in Ehrlichia chaffeensis during infection of mammalian cells. FEMS Microbiol Lett 2017; 364:3071827. [PMID: 28333306 PMCID: PMC5399918 DOI: 10.1093/femsle/fnx059] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 03/11/2017] [Indexed: 12/21/2022] Open
Abstract
Ehrlichia chaffeensis is an obligatory intracellular pathogen transmitted through infected ticks to humans and other vertebrates. We investigated the extent of protein aggregation in E. chaffeensis during infection of canine macrophage cell line, DH82. We discovered that the size of the aggregated fraction of E. chaffeensis proteins increased during the first 48 h post infection. We also incubated the infected cells with guanidinium chloride (GuHCl), a known inhibitor of the protein-disaggregating molecular chaperone ClpB. Up to 0.5 mM GuHCl had no impact on the host cells, whereas the viability of the pathogen was reduced by ∼60% in the presence of the inhibitor. Furthermore, we found that the size of the aggregated protein fraction in E. chaffeensis increased significantly in cultures supplemented with 0.5 mM GuHCl, which also resulted in the preferential accumulation of ClpB with the aggregated proteins. Altogether, our results suggest that an exposure of E. chaffeensis to the stressful environment of a host cell results in an increased aggregation of the pathogen's proteins, which is exacerbated upon inhibition of ClpB. Our studies establish a link between protein quality control and pathogen survival during infection of a host.
Collapse
Affiliation(s)
- Dorota Kuczynska-Wisnik
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506, USA.,Center of Excellence for Vector-Borne Diseases, Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA
| | - Chuanmin Cheng
- Center of Excellence for Vector-Borne Diseases, Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA
| | - Roman R Ganta
- Center of Excellence for Vector-Borne Diseases, Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA
| | - Michal Zolkiewski
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506, USA
| |
Collapse
|
16
|
Rossi F, Zotta T, Iacumin L, Reale A. Theoretical insight into the heat shock response (HSR) regulation in Lactobacillus casei and L. rhamnosus. J Theor Biol 2016; 402:21-37. [DOI: 10.1016/j.jtbi.2016.04.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Revised: 04/18/2016] [Accepted: 04/25/2016] [Indexed: 02/07/2023]
|
17
|
Abstract
Lactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g., Lactococcus lactis), probiotic (e.g., several Lactobacillus spp.), and pathogenic (e.g., Enterococcus and Streptococcus spp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the "stressome" of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance.
Collapse
|
18
|
Cassenego APV, de Oliveira NEM, Laport MS, Abranches J, Lemos JA, Giambiagi-deMarval M. The CtsR regulator controls the expression of clpC, clpE and clpP and is required for the virulence of Enterococcus faecalis in an invertebrate model. Antonie van Leeuwenhoek 2016; 109:1253-9. [DOI: 10.1007/s10482-016-0727-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/28/2016] [Indexed: 10/21/2022]
|
19
|
Lee C, Wigren E, Lünsdorf H, Römling U. Protein homeostasis-more than resisting a hot bath. Curr Opin Microbiol 2016; 30:147-154. [PMID: 26974352 DOI: 10.1016/j.mib.2016.02.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 02/10/2016] [Accepted: 02/22/2016] [Indexed: 12/13/2022]
Abstract
Maintenance of protein homeostasis is essential for survival of all organisms. In bacteria, the protein quality control system has a broad physiological impact beyond heat shock resistance, being involved in virulence, antibiotic resistance, as well as protection against environmental stresses. Its contribution to rejuvenation and growth arrest suggests interference with protein quality control to be a novel antimicrobial strategy. Remarkably, a protein quality control module originating from environmental strains has been found to be horizontally transferred to predominant clonal groups of bacteria providing exquisite thermotolerance to recently emerged global pathogens suggesting that novel features related to protein homeostasis contribute to the transition to new environments.
Collapse
Affiliation(s)
- Changhan Lee
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm 171 77, Sweden.
| | - Edvard Wigren
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 171 77, Sweden
| | - Heinrich Lünsdorf
- The Helmholtz Center for Infection Research, Braunschweig 38124, Germany
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm 171 77, Sweden.
| |
Collapse
|
20
|
Tsai CJY, Loh JMS, Proft T. Galleria mellonella infection models for the study of bacterial diseases and for antimicrobial drug testing. Virulence 2016; 7:214-29. [PMID: 26730990 PMCID: PMC4871635 DOI: 10.1080/21505594.2015.1135289] [Citation(s) in RCA: 445] [Impact Index Per Article: 55.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Galleria mellonella (greater wax moth or honeycomb moth) has been introduced as an alternative model to study microbial infections. G. mellonella larvae can be easily and inexpensively obtained in large numbers and are simple to use as they don't require special lab equipment. There are no ethical constraints and their short life cycle makes them ideal for large-scale studies. Although insects lack an adaptive immune response, their innate immune response shows remarkable similarities with the immune response in vertebrates. This review gives a current update of what is known about the immune system of G. mellonella and provides an extensive overview of how G. mellonella is used to study the virulence of Gram-positive and Gram-negative bacteria. In addition, the use of G. mellonella to evaluate the efficacy of antimicrobial agents and experimental phage therapy are also discussed. The review concludes with a critical assessment of the current limitatons of G. mellonella infection models.
Collapse
Affiliation(s)
- Catherine Jia-Yun Tsai
- a Department of Molecular Medicine & Pathology , School of Medical Sciences, University of Auckland , Auckland , New Zealand.,b Maurice Wilkins Center, University of Auckland , Auckland , New Zealand
| | - Jacelyn Mei San Loh
- a Department of Molecular Medicine & Pathology , School of Medical Sciences, University of Auckland , Auckland , New Zealand.,b Maurice Wilkins Center, University of Auckland , Auckland , New Zealand
| | - Thomas Proft
- a Department of Molecular Medicine & Pathology , School of Medical Sciences, University of Auckland , Auckland , New Zealand.,b Maurice Wilkins Center, University of Auckland , Auckland , New Zealand
| |
Collapse
|
21
|
Abstract
Pathogenic bacteria sense environmental cues, including the local temperature, to control the production of key virulence factors. Thermal regulation can be achieved at the level of DNA, RNA or protein and although many virulence factors are subject to thermal regulation, the exact mechanisms of control are yet to be elucidated in many instances. Understanding how virulence factors are regulated by temperature presents a significant challenge, as gene expression and protein production are often influenced by complex regulatory networks involving multiple transcription factors in bacteria. Here we highlight some recent insights into thermal regulation of virulence in pathogenic bacteria. We focus on bacteria which cause disease in mammalian hosts, which are at a significantly higher temperature than the outside environment. We outline the mechanisms of thermal regulation and how understanding this fundamental aspect of the biology of bacteria has implications for pathogenesis and human health.
Collapse
Affiliation(s)
- Oliver Lam
- a The Sir William Dunn School of Pathology ; University of Oxford ; Oxford , UK
| | | | | |
Collapse
|
22
|
Ye Y, Li H, Ling N, Han Y, Wu Q, Xu X, Jiao R, Gao J. Identification of potential virulence factors of Cronobacter sakazakii isolates by comparative proteomic analysis. Int J Food Microbiol 2015; 217:182-8. [PMID: 26546912 DOI: 10.1016/j.ijfoodmicro.2015.08.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Revised: 08/24/2015] [Accepted: 08/30/2015] [Indexed: 01/18/2023]
Abstract
Cronobacter is a group of important foodborne pathogens associated with neonatal meningitis, septicemia, and necrotizing enterocolitis. Among Cronobacter species, Cronobacter sakazakii is the most common species in terms of isolation frequency. However, the molecular basis involved in virulence differences among C. sakazakii isolates is still unknown. In this study, based on the determination of virulence differences of C. sakazakii G362 (virulent isolate) and L3101 (attenuated isolate) through intraperitoneal injection, histopathologic analysis (small intestine, kidney, and liver) further confirmed virulence differences. Thereafter, the potential virulence factors were determined using two-dimensional electrophoresis (2-DE) coupled with MALDI/TOP/TOF mass spectrometry. Among a total of 36 protein spots showing differential expression (fold change>1.2), we identified 31 different proteins, of which the expression abundance of 22 was increased in G362. These up-regulated proteins in G362 mainly contained DNA starvation/stationary phase protection protein Dps, OmpA, LuxS, ATP-dependent Clp protease ClpC, and ABC transporter substrate-binding proteins, which might be involved in virulence of C. sakazakii. This is the first report to determine the potential virulence factors of C. sakazakii isolates at the proteomic levels.
Collapse
Affiliation(s)
- Yingwang Ye
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China; State Key Laboratory of Applied Microbiology, South China (the Ministry-Province Joint Development), Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China
| | - Hui Li
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China
| | - Na Ling
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China; State Key Laboratory of Applied Microbiology, South China (the Ministry-Province Joint Development), Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China
| | - Yongjia Han
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China
| | - Qingping Wu
- State Key Laboratory of Applied Microbiology, South China (the Ministry-Province Joint Development), Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China.
| | - Xiaoke Xu
- State Key Laboratory of Applied Microbiology, South China (the Ministry-Province Joint Development), Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China
| | - Rui Jiao
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China
| | - Jina Gao
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China
| |
Collapse
|
23
|
Simultaneous Host-Pathogen Transcriptome Analysis during Granulibacter bethesdensis Infection of Neutrophils from Healthy Subjects and Patients with Chronic Granulomatous Disease. Infect Immun 2015; 83:4277-92. [PMID: 26283340 DOI: 10.1128/iai.00778-15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 08/11/2015] [Indexed: 11/20/2022] Open
Abstract
Polymorphonuclear leukocytes (PMN) from patients with chronic granulomatous disease (CGD) fail to produce microbicidal concentrations of reactive oxygen species (ROS) due to mutations in NOX2. Patients with CGD suffer from severe, life-threatening infections and inflammatory complications. Granulibacter bethesdensis is an emerging Gram-negative pathogen in CGD that resists killing by PMN of CGD patients (CGD PMN) and inhibits PMN apoptosis through unknown mechanisms. Microarray analysis was used to study mRNA expression in PMN from healthy subjects (normal PMN) and CGD PMN during incubation with G. bethesdensis and, simultaneously, in G. bethesdensis with normal and CGD PMN. We detected upregulation of antiapoptotic genes (e.g., XIAP and GADD45B) and downregulation of proapoptotic genes (e.g., CASP8 and APAF1) in infected PMN. Transcript and protein levels of inflammation- and immunity-related genes were also altered. Upon interaction with PMN, G. bethesdensis altered the expression of ROS resistance genes in the presence of normal but not CGD PMN. Levels of bacterial stress response genes, including the ClpB gene, increased during phagocytosis by both normal and CGD PMN demonstrating responses to oxygen-independent PMN antimicrobial systems. Antisense knockdown demonstrated that ClpB is dispensable for extracellular growth but is essential for bacterial resistance to both normal and CGD PMN. Metabolic adaptation of Granulibacter growth in PMN included the upregulation of pyruvate dehydrogenase. Pharmacological inhibition of pyruvate dehydrogenase by triphenylbismuthdichloride was lethal to Granulibacter. This study expands knowledge of microbial pathogenesis of Granulibacter in cells from permissive (CGD) and nonpermissive (normal) hosts and identifies potentially druggable microbial factors, such as pyruvate dehydrogenase and ClpB, to help combat this antibiotic-resistant pathogen.
Collapse
|
24
|
Muller C, Cacaci M, Sauvageot N, Sanguinetti M, Rattei T, Eder T, Giard JC, Kalinowski J, Hain T, Hartke A. The Intraperitoneal Transcriptome of the Opportunistic Pathogen Enterococcus faecalis in Mice. PLoS One 2015; 10:e0126143. [PMID: 25978463 PMCID: PMC4433114 DOI: 10.1371/journal.pone.0126143] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 03/29/2015] [Indexed: 01/22/2023] Open
Abstract
Enterococcus faecalis is a Gram-positive lactic acid intestinal opportunistic bacterium with virulence potential. For a better understanding of the adapation of this bacterium to the host conditions, we performed a transcriptome analysis of bacteria isolated from an infection site (mouse peritonitis) by RNA-sequencing. We identified a total of 211 genes with significantly higher transcript levels and 157 repressed genes. Our in vivo gene expression database reflects well the infection process since genes encoding important virulence factors like cytolysin, gelatinase or aggregation substance as well as stress response proteins, are significantly induced. Genes encoding metabolic activities are the second most abundant in vivo induced genes demonstrating that the bacteria are metabolically active and adapt to the special nutrient conditions of the host. α- and β- glucosides seem to be important substrates for E. faecalis inside the host. Compared to laboratory conditions, the flux through the upper part of glycolysis seems to be reduced and more carbon may enter the pentose phosphate pathway. This may reflect the need of the bacteria under infection conditions to produce more reducing power for biosynthesis. Another important substrate is certainly glycerol since both pathways of glycerol catabolism are strongly induced. Strongly in vivo induced genes should be important for the infection process. This assumption has been verified in a virulence test using well characterized mutants affected in glycerol metabolism. This showed indeed that mutants unable to metabolize this sugar alcohol are affected in organ colonisation in a mouse model.
Collapse
Affiliation(s)
- Cécile Muller
- U2RM-Stress and Virulence, University of Caen Basse-Normandie, EA4655, 14032 Caen, France
- * E-mail: (AH); (CM)
| | - Margherita Cacaci
- U2RM-Stress and Virulence, University of Caen Basse-Normandie, EA4655, 14032 Caen, France
- Institute of Microbiology, Catholic University of Sacred Heart, 00168, Rome, Italy
| | - Nicolas Sauvageot
- U2RM-Stress and Virulence, University of Caen Basse-Normandie, EA4655, 14032 Caen, France
| | - Maurizio Sanguinetti
- Institute of Microbiology, Catholic University of Sacred Heart, 00168, Rome, Italy
| | - Thomas Rattei
- CUBE-Division for Computational Systems Biology, Dept. of Microbiology and Ecosystem Science, University of Vienna, 1090 Vienna, Austria
| | - Thomas Eder
- CUBE-Division for Computational Systems Biology, Dept. of Microbiology and Ecosystem Science, University of Vienna, 1090 Vienna, Austria
| | - Jean-Christophe Giard
- U2RM-Stress and Virulence, University of Caen Basse-Normandie, EA4655, 14032 Caen, France
| | - Jörn Kalinowski
- Center for Biotechnology, Bielefeld University, 33594 Bielefeld, Germany
| | - Torsten Hain
- Institute of Medicine Microbiology, Gießen University, 35392 Gießen, Germany
| | - Axel Hartke
- U2RM-Stress and Virulence, University of Caen Basse-Normandie, EA4655, 14032 Caen, France
- * E-mail: (AH); (CM)
| |
Collapse
|
25
|
Frank KL, Colomer-Winter C, Grindle SM, Lemos JA, Schlievert PM, Dunny GM. Transcriptome analysis of Enterococcus faecalis during mammalian infection shows cells undergo adaptation and exist in a stringent response state. PLoS One 2014; 9:e115839. [PMID: 25545155 PMCID: PMC4278851 DOI: 10.1371/journal.pone.0115839] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 12/01/2014] [Indexed: 11/30/2022] Open
Abstract
As both a commensal and a major cause of healthcare-associated infections in humans, Enterococcus faecalis is a remarkably adaptable organism. We investigated how E. faecalis adapts in a mammalian host as a pathogen by characterizing changes in the transcriptome during infection in a rabbit model of subdermal abscess formation using transcriptional microarrays. The microarray experiments detected 222 and 291 differentially regulated genes in E. faecalis OG1RF at two and eight hours after subdermal chamber inoculation, respectively. The profile of significantly regulated genes at two hours post-inoculation included genes involved in stress response, metabolism, nutrient acquisition, and cell surface components, suggesting genome-wide adaptation to growth in an altered environment. At eight hours post-inoculation, 88% of the differentially expressed genes were down-regulated and matched a transcriptional profile consistent with a (p)ppGpp-mediated stringent response. Subsequent subdermal abscess infections with E. faecalis mutants lacking the (p)ppGpp synthetase/hydrolase RSH, the small synthetase RelQ, or both enzymes, suggest that intracellular (p)ppGpp levels, but not stringent response activation, influence persistence in the model. The ability of cells to synthesize (p)ppGpp was also found to be important for growth in human serum and whole blood. The data presented in this report provide the first genome-wide insights on E. faecalis in vivo gene expression and regulation measured by transcriptional profiling during infection in a mammalian host and show that (p)ppGpp levels affect viability of E. faecalis in multiple conditions relevant to mammalian infection. The subdermal abscess model can serve as a novel experimental system for studying the E. faecalis stringent response in the context of the mammalian immune system.
Collapse
Affiliation(s)
- Kristi L. Frank
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Cristina Colomer-Winter
- Center for Oral Biology and Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Suzanne M. Grindle
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - José A. Lemos
- Center for Oral Biology and Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Patrick M. Schlievert
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Gary M. Dunny
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| |
Collapse
|
26
|
Yuen GJ, Ausubel FM. Enterococcus infection biology: lessons from invertebrate host models. J Microbiol 2014; 52:200-10. [PMID: 24585051 PMCID: PMC4556283 DOI: 10.1007/s12275-014-4011-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 01/21/2014] [Indexed: 12/29/2022]
Abstract
The enterococci are commensals of the gastrointestinal tract of many metazoans, from insects to humans. While they normally do not cause disease in the intestine, they can become pathogenic when they infect sites outside of the gut. Recently, the enterococci have become important nosocomial pathogens, with the majority of human enterococcal infections caused by two species, Enterococcus faecalis and Enterococcus faecium. Studies using invertebrate infection models have revealed insights into the biology of enterococcal infections, as well as general principles underlying host innate immune defense. This review highlights recent findings on Enterococcus infection biology from two invertebrate infection models, the greater wax moth Galleria mellonella and the free-living bacteriovorous nematode Caenorhabditis elegans.
Collapse
Affiliation(s)
- Grace J. Yuen
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - Frederick M. Ausubel
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| |
Collapse
|
27
|
Abranches J, Tijerina P, Avilés-Reyes A, Gaca AO, Kajfasz JK, Lemos JA. The cell wall-targeting antibiotic stimulon of Enterococcus faecalis. PLoS One 2013; 8:e64875. [PMID: 23755154 PMCID: PMC3670847 DOI: 10.1371/journal.pone.0064875] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 04/19/2013] [Indexed: 02/06/2023] Open
Abstract
Enterococcus faecalis is an opportunistic nosocomial pathogen that is highly resistant to a variety of environmental insults, including an intrinsic tolerance to antimicrobials that target the cell wall (CW). With the goal of determining the CW-stress stimulon of E. faecalis, the global transcriptional profile of E. faecalis OG1RF exposed to ampicillin, bacitracin, cephalotin or vancomycin was obtained via microarrays. Exposure to the β-lactams ampicillin and cephalotin resulted in the fewest transcriptional changes with 50 and 192 genes differentially expressed 60 min after treatment, respectively. On the other hand, treatment with bacitracin or vancomycin for 60 min affected the expression of, respectively, 377 and 297 genes. Despite the differences in the total number of genes affected, all antibiotics induced a very similar gene expression pattern with an overrepresentation of genes encoding hypothetical proteins, followed by genes encoding proteins associated with cell envelope metabolism as well as transport and binding proteins. In particular, all drug treatments, most notably bacitracin and vancomycin, resulted in an apparent metabolic downshift based on the repression of genes involved in translation, energy metabolism, transport and binding. Only 19 genes were up-regulated by all conditions at both the 30 and 60 min time points. Among those 19 genes, 4 genes encoding hypothetical proteins (EF0026, EF0797, EF1533 and EF3245) were inactivated and the respective mutant strains characterized in relation to antibiotic tolerance and virulence in the Galleria mellonella model. The phenotypes obtained for two of these mutants, ΔEF1533 and ΔEF3245, support further characterization of these genes as potential candidates for the development of novel preventive or therapeutic approaches.
Collapse
Affiliation(s)
- Jacqueline Abranches
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Pamella Tijerina
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Alejandro Avilés-Reyes
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Anthony O. Gaca
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Jessica K. Kajfasz
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - José A. Lemos
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
- * E-mail:
| |
Collapse
|
28
|
Aggregate-reactivation activity of the molecular chaperone ClpB from Ehrlichia chaffeensis. PLoS One 2013; 8:e62454. [PMID: 23667479 PMCID: PMC3646808 DOI: 10.1371/journal.pone.0062454] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 03/20/2013] [Indexed: 11/23/2022] Open
Abstract
Rickettsiale diseases, including human monocytic ehrlichiosis caused by Ehrlichia chaffeensis, are the second leading cause of the tick-borne infections in the USA and a growing health concern. Little is known about how E. chaffeensis survives the host-induced stress in vertebrate and tick hosts. A molecular chaperone ClpB from several microorganisms has been reported to reactivate aggregated proteins in cooperation with the co-chaperones DnaK/DnaJ/GrpE (KJE). In this study, we performed the first biochemical characterization of ClpB from E. chaffeensis. The transcript of E. chaffeensis ClpB (EhClpB) is strongly upregulated after infection of cultured macrophages and its level remains high during the Ehrlichia replicative stage. EhClpB forms ATP-dependent oligomers and catalyzes the ATP hydrolysis, similar to E. coli ClpB (EcClpB), but its ATPase activity is insensitive to the EcClpB activators, casein and poly-lysine. EhClpB in the presence of E. coli KJE efficiently reactivates the aggregated glucose-6-phosphate dehydrogenase (G6PDH) and firefly luciferase. Unlike EcClpB, which requires the co-chaperones for aggregate reactivation, EhClpB reactivates G6PDH even in the absence of KJE. Moreover, EhClpB is functionally distinct from EcClpB as evidenced by its failure to rescue a temperature-sensitive phenotype of the clpB-null E. coli. The clpB expression pattern during the E. chaffeensis infection progression correlates with the pathogen’s replicating stage inside host cells and suggests an essential role of the disaggregase activity of ClpB in the pathogen’s response to the host-induced stress. This study sets the stage for assessing the importance of the chaperone activity of ClpB for E. chaffeensis growth within the mammalian and tick hosts.
Collapse
|
29
|
Campbell AG, Campbell JH, Schwientek P, Woyke T, Sczyrba A, Allman S, Beall CJ, Griffen A, Leys E, Podar M. Multiple single-cell genomes provide insight into functions of uncultured Deltaproteobacteria in the human oral cavity. PLoS One 2013; 8:e59361. [PMID: 23555659 PMCID: PMC3608642 DOI: 10.1371/journal.pone.0059361] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 02/13/2013] [Indexed: 01/10/2023] Open
Abstract
Despite a long history of investigation, many bacteria associated with the human oral cavity have yet to be cultured. Studies that correlate the presence or abundance of uncultured species with oral health or disease highlight the importance of these community members. Thus, we sequenced several single-cell genomic amplicons from Desulfobulbus and Desulfovibrio (class Deltaproteobacteria) to better understand their function within the human oral community and their association with periodontitis, as well as other systemic diseases. Genomic data from oral Desulfobulbus and Desulfovibrio species were compared to other available deltaproteobacterial genomes, including from a subset of host-associated species. While both groups share a large number of genes with other environmental Deltaproteobacteria genomes, they encode a wide array of unique genes that appear to function in survival in a host environment. Many of these genes are similar to virulence and host adaptation factors of known human pathogens, suggesting that the oral Deltaproteobacteria have the potential to play a role in the etiology of periodontal disease.
Collapse
Affiliation(s)
- Alisha G. Campbell
- Genome Science and Technology Program, University of Tennessee, Knoxville, Tennessee, United States of America
- Biosciences Division, Oak Ridge National Laboratories, Oak Ridge, Tennessee, United States of America
| | - James H. Campbell
- Biosciences Division, Oak Ridge National Laboratories, Oak Ridge, Tennessee, United States of America
| | - Patrick Schwientek
- DOE Joint Genome Institute, Walnut Creek, California, United States of America
| | - Tanja Woyke
- DOE Joint Genome Institute, Walnut Creek, California, United States of America
| | - Alexander Sczyrba
- DOE Joint Genome Institute, Walnut Creek, California, United States of America
| | - Steve Allman
- Biosciences Division, Oak Ridge National Laboratories, Oak Ridge, Tennessee, United States of America
| | - Clifford J. Beall
- College of Dentistry, Ohio State University, Columbus, Ohio, United States of America
| | - Ann Griffen
- College of Dentistry, Ohio State University, Columbus, Ohio, United States of America
| | - Eugene Leys
- College of Dentistry, Ohio State University, Columbus, Ohio, United States of America
| | - Mircea Podar
- Genome Science and Technology Program, University of Tennessee, Knoxville, Tennessee, United States of America
- Biosciences Division, Oak Ridge National Laboratories, Oak Ridge, Tennessee, United States of America
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, United States of America
| |
Collapse
|
30
|
Utility of insects for studying human pathogens and evaluating new antimicrobial agents. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2013; 135:1-25. [PMID: 23604210 DOI: 10.1007/10_2013_194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
Abstract
Insect models, such as Galleria mellonella and Drosophila melanogaster have significant ethical, logistical, and economic advantages over mammalian models for the studies of infectious diseases. Using these models, various pathogenic microbes have been studied and many novel virulence genes have been identified. Notably, because insects are susceptible to a wide variety of human pathogens and have immune responses similar to those of mammals, they offer the opportunity to understand innate immune responses against human pathogens better. It is important to note that insect pathosystems have also offered a simple strategy to evaluate the efficacy and toxicity of many antimicrobial agents. Overall, insect models provide a rapid, inexpensive, and reliable way as complementary hosts to conventional vertebrate animal models to study pathogenesis and antimicrobial agents.
Collapse
|
31
|
The C-terminus of ClpC1 of Mycobacterium tuberculosis is crucial for its oligomerization and function. PLoS One 2012; 7:e51261. [PMID: 23284674 PMCID: PMC3527473 DOI: 10.1371/journal.pone.0051261] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2012] [Accepted: 10/30/2012] [Indexed: 11/19/2022] Open
Abstract
Mycobacterium tuberculosis ClpC1 is a member of the Hsp100/Clp AAA+ family of ATPases. The primary sequence of ClpC1 contains two N-terminal domains and two nucleotide binding domains (NBD). The second NBD has a long C-terminal sub-domain containing several motifs important for substrate interaction. Generally, ClpC proteins are highly conserved, however presence of C-terminal domains of variable lengths is a remarkable difference in ClpC from different species. In this study, we constructed deletion mutants at the C-terminus of M. tuberculosis ClpC1 to determine its role in the structure and function of the protein. In addition, a deletion mutant having the two conserved N-terminal domains deleted was also constructed to investigate the role of these domains in M. tuberculosis ClpC1 function. The N-terminal domains were found to be dispensable for the formation of oligomeric structure, and ATPase and chaperone activities. However, deletions beyond a specific region in the C-terminus of the ClpC1 resulted in oligomerization defects and loss of chaperonic activity of the protein without affecting its ATPase activity. The truncated mutants, defective in oligomerization were also found to have lost the chaperonic activity, showing the formation of oligomer to be required for the chaperonic activity of M. tuberculosis ClpC1. The current study has identified a region in the C-terminus of M. tuberculosis ClpC1 which is essential for its oligomerization and in turn its function.
Collapse
|
32
|
Pan H, Luan J, He X, Lux R, Shi W. The clpB gene is involved in the stress response of Myxococcus xanthus during vegetative growth and development. MICROBIOLOGY-SGM 2012; 158:2336-2343. [PMID: 22790397 DOI: 10.1099/mic.0.060103-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The Clp/HSP100 family of molecular chaperones is ubiquitous in both prokaryotes and eukaryotes. These proteins play important roles in refolding, disaggregating and degrading proteins damaged by stress. As a subclass of the Clp/HSP100 family, ClpB has been shown to be involved in various stress responses as well as other functions in bacteria. In the present study, we investigated the role of a predicted ClpB-encoding gene, MXAN5092, in the stress response during vegetative growth and development of Myxococcus xanthus. Transcriptional analysis confirmed induction of this clpB homologue under different stress conditions, and further phenotypic analysis revealed that an in-frame deletion mutant of MXAN5092 was more sensitive to various stress treatments than the wild-type strain during vegetative growth. Moreover, the absence of the MXAN5092 gene resulted in decreased heat tolerance of myxospores, indicating the involvement of this clpB homologue in the stress response during the development of myxospores. The M. xanthus recombinant ClpB (MXAN5092) protein also showed a general chaperone activity in vitro. Overall, our genetic and phenotypic analysis of the predicted ATP-dependent chaperone protein ClpB (MXAN5092) demonstrated that it functions as a chaperone protein and plays an important role in cellular stress tolerance during both vegetative growth and development of M. xanthus.
Collapse
Affiliation(s)
- Hongwei Pan
- School of Dentistry, University of California, Los Angeles, CA 90095, USA
| | - Jia Luan
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Xuesong He
- School of Dentistry, University of California, Los Angeles, CA 90095, USA
| | - Renate Lux
- School of Dentistry, University of California, Los Angeles, CA 90095, USA
| | - Wenyuan Shi
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA.,School of Dentistry, University of California, Los Angeles, CA 90095, USA
| |
Collapse
|
33
|
Gaca AO, Abranches J, Kajfasz JK, Lemos JA. Global transcriptional analysis of the stringent response in Enterococcus faecalis. MICROBIOLOGY-SGM 2012; 158:1994-2004. [PMID: 22653948 DOI: 10.1099/mic.0.060236-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In Enterococcus faecalis, production of guanosine tetraphosphate/guanosine pentaphosphate [(p)ppGpp], the effector molecule of the stringent response, is controlled by the bifunctional synthetase/hydrolase RelA and the monofunctional synthetase RelQ. Previously, the (p)ppGpp profiles of strains lacking relA, relQ or both genes indicated that RelA is the primary enzyme responsible for (p)ppGpp synthesis under stress conditions, while the contributions of RelQ to the stringent response and cell homeostasis remained elusive. Here, survival within the mouse-derived macrophage cell line J774A.1 and killing of Galleria mellonella supported initial evidence that virulence was attenuated in the (p)ppGpp(0) ΔrelAΔrelQ strain but not in the ΔrelA or ΔrelQ strains. We performed, for the first time to our knowledge, global transcriptome analysis in a documented (p)ppGpp(0) Gram-positive bacterium and provided the first insights into the role of a Gram-positive monofunctional (p)ppGpp synthetase in transcriptional regulation. Transcription profiling after mupirocin treatment confirmed that RelA is the major enzyme responsible for the (p)ppGpp-mediated transcriptional repression of genes associated with macromolecular biosynthesis, but also revealed that RelQ is required for full and timely stringent response induction. The delayed transcriptional response of ΔrelQ could not be correlated with reduced or slower production of (p)ppGpp, in part because RelA-dependent (p)ppGpp accumulation occurred very rapidly. Comparisons of the transcriptional responses of ΔrelA or ΔrelAΔrelQ strains with the parent strain under starvation conditions revealed upregulation of operons involved in energy metabolism in the (p)ppGpp(0) strain. Thus, while ΔrelA and ΔrelAΔrelQ cannot use (p)ppGpp to sense and respond to stresses, fitness of ΔrelAΔrelQ may be further impaired due to an unbalanced metabolism.
Collapse
Affiliation(s)
- Anthony O Gaca
- Center for Oral Biology and Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Jacqueline Abranches
- Center for Oral Biology and Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Jessica K Kajfasz
- Center for Oral Biology and Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - José A Lemos
- Center for Oral Biology and Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
| |
Collapse
|
34
|
Zolkiewski M, Zhang T, Nagy M. Aggregate reactivation mediated by the Hsp100 chaperones. Arch Biochem Biophys 2012; 520:1-6. [PMID: 22306514 DOI: 10.1016/j.abb.2012.01.012] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 01/16/2012] [Accepted: 01/17/2012] [Indexed: 11/16/2022]
Abstract
Hsp100 family of molecular chaperones shows a unique capability to resolubilize and reactivate aggregated proteins. The Hsp100-mediated protein disaggregation is linked to the activity of other chaperones from the Hsp70 and Hsp40 families. The best-studied members of the Hsp100 family are the bacterial ClpB and Hsp104 from yeast. Hsp100 chaperones are members of a large super-family of energy-driven conformational "machines" known as AAA+ ATPases. This review describes the current mechanistic model of the chaperone-induced protein disaggregation and explains how the structural architecture of Hsp100 supports disaggregation and how the co-chaperones may participate in the Hsp100-mediated reactions.
Collapse
Affiliation(s)
- Michal Zolkiewski
- Department of Biochemistry, Kansas State University, Manhattan, 66506, USA.
| | | | | |
Collapse
|