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Cun WY, Keller PA, Pyne SG. Current and Ongoing Developments in Targeting Clostridioides difficile Infection and Recurrence. Microorganisms 2024; 12:1206. [PMID: 38930588 PMCID: PMC11205563 DOI: 10.3390/microorganisms12061206] [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: 04/24/2024] [Revised: 06/11/2024] [Accepted: 06/13/2024] [Indexed: 06/28/2024] Open
Abstract
Clostridioides difficile is a Gram-positive, spore-forming anaerobic bacterial pathogen that causes severe gastrointestinal infection in humans. This review provides background information on C. difficile infection and the pathogenesis and toxigenicity of C. difficile. The risk factors, causes, and the problem of recurrence of disease and current therapeutic treatments are also discussed. Recent therapeutic developments are reviewed including small molecules that inhibit toxin formation, disrupt the cell membrane, inhibit the sporulation process, and activate the host immune system in cells. Other treatments discussed include faecal microbiota treatment, antibody-based immunotherapies, probiotics, vaccines, and violet-blue light disinfection.
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Affiliation(s)
- Wendy Y. Cun
- School of Chemistry and Molecular Science, Molecular Horizons Institute, University of Wollongong, Wollongong, NSW 2522, Australia;
| | | | - Stephen G. Pyne
- School of Chemistry and Molecular Science, Molecular Horizons Institute, University of Wollongong, Wollongong, NSW 2522, Australia;
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2
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Yu XH, Lv Z, Zhang CE, Gao Y, Li H, Ma XJ, Ma ZJ, Su JR, Huang LQ. Shengjiang Xiexin decoction mitigates murine Clostridium difficile infection through modulation of the gut microbiota and bile acid metabolism. JOURNAL OF ETHNOPHARMACOLOGY 2024; 320:117384. [PMID: 37925000 DOI: 10.1016/j.jep.2023.117384] [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: 06/20/2023] [Revised: 10/30/2023] [Accepted: 11/01/2023] [Indexed: 11/06/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The overuse of antibiotics has resulted in Clostridium difficile infection (CDI) as a significant global public health concern. Studies have shown that imbalances in gut microbiota and metabolism play a vital role in the onset of CDI. Shengjiang Xiexin decoction (SJT), a traditional Chinese medicinal formula widely employed in the treatment of gastrointestinal ailments, demonstrates effectiveness in addressing murine CDI. However, the precise mechanistic role of SJT in CDI treatment remains uncertain, particularly regarding its impact on gut microbiota and intestinal metabolism. Thus, further investigation is imperative to shed light on these mechanisms. AIM OF THE STUDY This study aims to thoroughly investigate the therapeutic potential of SJT in the treatment of CDI, while also examining its impact on the intricate interplay between gut microbiota and bile acid metabolism. By employing a mouse model, we aspire to uncover novel insights that could pave the way for the development of more effective strategies in combating CDI. MATERIALS AND METHODS We developed a mouse model for CDI and assessed SJT's potential as a therapeutic agent through pharmacological analyses. Our study employed high-throughput sequencing of 16S rRNA to identify changes in gut microbiota composition and untargeted metabolomics analysis to evaluate SJT's intervention on intestinal metabolism. We also conducted targeted analysis of bile acid metabolism to examine the specific effects of SJT. Finally, the growth-inhibitory effect of SJT on C. difficile was confirmed through ex vivo cultivation of the pathogen using cecal contents, supporting its potential role in treating CDI by modulating gut microbiota and bile acid metabolism. RESULTS In pharmacological studies, SJT was found to effectively reduce the levels of A&B toxins and alleviate colonic inflammation in CDI mice. Mechanistically, SJT demonstrated a mild increase in the abundance and diversity of the gut microbiota. However, its most significant impact was observed in the substantial improvement of the structural composition of the gut microbiota. Specifically, SJT decreased the abundance of gut Polymorphs and Firmicutes while restoring the proportions of family Trichophyton and Bacteroides_S24-7 spp (P < 0.001). Moreover, SJT not only decreased the levels of primary bile acids but also elevated the levels of secondary bile acids. Notably, it enhanced the conversion of taurocholic acid (TCA) to deoxycholic acid (DCA), leading to a balanced bile acid metabolism. Finally, cecal contents of SJT-treated mice showed a significant reduction in the growth of C. difficile, underscoring the therapeutic potential of SJT via modulation of gut microbiota and bile acid metabolism. CONCLUSION SJT demonstrates remarkable efficacy in treating CDI in mice by not only effectively combating the infection but also restoring the intricate balance of gut microbiota and bile acid metabolism. Furthermore, promising indications suggest that SJT may have the potential to prevent CDI recurrence. These findings underscore the comprehensive therapeutic value of SJT in managing CDI. Moving forward, we plan to transition from the laboratory to clinical settings to conduct further studies, validating our conclusions on SJT's efficacy.
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Affiliation(s)
- Xiao-Hong Yu
- Department of Pharmacy, Beijing Friendship Hospital, Capital Medical University, 100050, Beijing, China
| | - Zhi Lv
- Clinical Laboratory Center, Beijing Friendship Hospital, Capital Medical University, 100050, Beijing, China
| | - Cong-En Zhang
- Department of Pharmacy, Beijing Friendship Hospital, Capital Medical University, 100050, Beijing, China
| | - Yan Gao
- Clinical Laboratory Center, Beijing Friendship Hospital, Capital Medical University, 100050, Beijing, China
| | - Hui Li
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Xiao-Jing Ma
- Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Zhi-Jie Ma
- Department of Pharmacy, Beijing Friendship Hospital, Capital Medical University, 100050, Beijing, China.
| | - Jian-Rong Su
- Clinical Laboratory Center, Beijing Friendship Hospital, Capital Medical University, 100050, Beijing, China.
| | - Lu-Qi Huang
- Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
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3
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Sharma SK, Schilke AR, Phan JR, Yip C, Sharma PV, Abel-Santos E, Firestine SM. The design, synthesis, and inhibition of Clostridioides difficile spore germination by acyclic and bicyclic tertiary amide analogs of cholate. Eur J Med Chem 2023; 261:115788. [PMID: 37703709 PMCID: PMC10680100 DOI: 10.1016/j.ejmech.2023.115788] [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: 06/01/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 09/15/2023]
Abstract
Clostridioides difficile infection (CDI) is a major identifiable cause of antibiotic-associated diarrhea. In our previous study (J. Med. Chem., 2018, 61, 6759-6778), we have identified N-phenyl-cholan-24-amide as a potent inhibitor of spore germination. The most potent compounds in our previous work are N-arylamides. We were interested in the role that the conformation of the amide plays in activity. Previous research has shown that secondary N-arylamides exist exclusively in the coplanar trans conformation while tertiary N-methyl-N-arylamides exist in a non-planar, cis conformation. The N-methyl-N-phenyl-cholan-24-amide was 17-fold less active compared to the parent compounds suggesting the importance of the orientation of the phenyl ring. To lock the phenyl ring into a trans conformation, cyclic tertiary amides were prepared. Indoline and quinoline cholan-24-amides were both inhibitors of spore germination; however, the indoline analogs were most potent. Isoindoline and isoquinoline amides were inactive. We found that the simple indoline derivative gave an IC50 value of 1 μM, while the 5'-fluoro-substituted compound (5d) possessed an IC50 of 400 nM. To our knowledge, 5d is the most potent known spore germination inhibitor described to date. Taken together, our results indicate that the trans, coplanar conformation of the phenyl ring is required for potent inhibition.
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Affiliation(s)
- Shiv K Sharma
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI, 48201, USA
| | - Angel R Schilke
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI, 48201, USA
| | - Jacqueline R Phan
- Department of Chemistry and Biochemistry, University of Nevada -Las Vegas, 4505 S. Maryland Pkwy, Las Vegas, NV, 89154, USA
| | - Christopher Yip
- Department of Chemistry and Biochemistry, University of Nevada -Las Vegas, 4505 S. Maryland Pkwy, Las Vegas, NV, 89154, USA
| | - Prateek V Sharma
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI, 48201, USA
| | - Ernesto Abel-Santos
- Department of Chemistry and Biochemistry, University of Nevada -Las Vegas, 4505 S. Maryland Pkwy, Las Vegas, NV, 89154, USA
| | - Steven M Firestine
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI, 48201, USA.
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4
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Kelly CR, Allegretti JR. Review Article: Gastroenterology and Clostridium difficile Infection: Past, Present, and Future. Clin Infect Dis 2023; 77:S463-S470. [PMID: 38051967 DOI: 10.1093/cid/ciad644] [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] [Indexed: 12/07/2023] Open
Abstract
Research and innovation around Clostridium difficile infection (CDI) has been a multidisciplinary endeavor since discovery of the organism in 1978. The field of gastroenterology has contributed to our understanding of CDI as a disease caused by disruptions in the gut microbiome and led to advances in therapeutic manipulation of gut microbiota, including fecal microbiota transplantation. The high incidence of CDI in patients with inflammatory bowel disease and treatment of the infection in this population have been of particular interest to gastroenterologists. The emergence of standardized, approved live biotherapeutic products for treatment of recurrent CDI is an inflection point in our management of this difficult clinical problem, and real-world performance of these therapies will inform optimal treatment algorithms.
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Affiliation(s)
- Colleen R Kelly
- Harvard Medical School, Boston, Massachusetts, USA
- Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Jessica R Allegretti
- Harvard Medical School, Boston, Massachusetts, USA
- Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
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5
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Li Y, Sun J, Wang X, Luo Z, Shao X, Li Y, Cao Q, Zhao S, Qian M, Chen X. Discovery and biological evaluation of cholic acid derivatives as potent TGR5 positive allosteric modulators. Bioorg Med Chem 2023; 92:117418. [PMID: 37536263 DOI: 10.1016/j.bmc.2023.117418] [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: 04/24/2023] [Revised: 07/16/2023] [Accepted: 07/17/2023] [Indexed: 08/05/2023]
Abstract
In this study, twenty-two novel cholic acid (CA) derivatives were designed and synthesized as potential Takeda G protein-coupled receptor 5 (TGR5) positive allosteric modulators (PAMs) using structure-based drug design (SBDD). GloSensor cAMP accumulation assay was employed to assess the functional activity and allosteric mechanism of final compounds. Biological results showed that all target compounds were able to activate the TGR5 in the cAMP formation assay. Remarkably, compound B1, selective methylation of 7-OH in CA, exhibited 5-fold higher activity for TGR5 compared to that of CA. Moreover, B1 positively modulate the functional activity of chenodeoxycholic acid (CDCA) in TGR5, indicating that B1 is a TGR5 PAM. On the other hand, 12-carbonyl derivative A1 displayed 7-fold higher potency for TGR5 relative to CA. Unexpectedly, compound A1 exhibited the same positive allosteric effect as B1, suggesting that A1 is a TGR5 PAM as well. Molecular modeling study revealed that 12-carbonyl in A1 and 12-OH in B1 formed H-bolds with the key amino acid Thr131, which are significant for TGR5 allosteric property. Taken together, we found two potent TGR5 PAMs A1 and B1 through SBDD, which could be used as lead compounds to further study TGR5 allosteric functionality.
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Affiliation(s)
- Yan Li
- School of Pharmacy, Changzhou University, Changzhou 213164, PR China
| | - Jingjing Sun
- School of Pharmacy, Changzhou University, Changzhou 213164, PR China
| | - Xiao Wang
- School of Pharmacy, Changzhou University, Changzhou 213164, PR China
| | - Zhijie Luo
- School of Pharmacy, Changzhou University, Changzhou 213164, PR China
| | - Xuemei Shao
- School of Pharmacy, Changzhou University, Changzhou 213164, PR China
| | - Yingxiu Li
- School of Pharmacy, Changzhou University, Changzhou 213164, PR China
| | - Qirong Cao
- School of Pharmacy, Changzhou University, Changzhou 213164, PR China
| | - Shuai Zhao
- School of Pharmacy, Changzhou University, Changzhou 213164, PR China
| | - Mingcheng Qian
- School of Pharmacy, Changzhou University, Changzhou 213164, PR China.
| | - Xin Chen
- School of Pharmacy, Changzhou University, Changzhou 213164, PR China.
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6
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Yip C, Phan JR, Abel-Santos E. Mechanism of germination inhibition of Clostridioides difficile spores by an aniline substituted cholate derivative (CaPA). J Antibiot (Tokyo) 2023; 76:335-345. [PMID: 37016015 PMCID: PMC10406169 DOI: 10.1038/s41429-023-00612-3] [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: 02/15/2023] [Revised: 02/28/2023] [Accepted: 03/07/2023] [Indexed: 04/06/2023]
Abstract
Clostridioides difficile infection (CDI) is the major identifiable cause of antibiotic-associated diarrhea and has been declared an urgent threat by the CDC. C. difficile forms dormant and resistant spores that serve as infectious vehicles for CDI. To cause disease, C. difficile spores recognize taurocholate and glycine to trigger the germination process. In contrast to other sporulating bacteria, C. difficile spores are postulated to use a protease complex, CspABC, to recognize its germinants. Since spore germination is required for infection, we have developed anti-germination approaches for CDI prophylaxis. Previously, the bile salt analog CaPA (an aniline-substituted cholic acid) was shown to block spore germination and protect rodents from CDI caused by multiple C. difficile strains and isolates. In this study, we found that CaPA is an alternative substrate inhibitor of C. difficile spore germination. By competing with taurocholate for binding, CaPA delays C. difficile spore germination and reduces spore viability, thus diminishing the number of outgrowing vegetative bacteria. We hypothesize that the reduction of toxin-producing bacterial burden explains CaPA's protective activity against murine CDI. Previous data combined with our results suggests that CaPA binds tightly to C. difficile spores in a CspC-dependent manner and irreversibly traps spores in an alternative, time-delayed, and low yield germination pathway. Our results are also consistent with kinetic data suggesting the existence of at least two distinct bile salt binding sites in C. difficile spores.
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Affiliation(s)
- Christopher Yip
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV, 89154, USA
| | - Jacqueline R Phan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV, 89154, USA
| | - Ernesto Abel-Santos
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV, 89154, USA.
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7
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Dorel R, Wong AR, Crawford JJ. Trust Your Gut: Strategies and Tactics for Intestinally Restricted Drugs. ACS Med Chem Lett 2023; 14:233-243. [PMID: 36923921 PMCID: PMC10009798 DOI: 10.1021/acsmedchemlett.3c00001] [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: 01/05/2023] [Accepted: 02/02/2023] [Indexed: 02/24/2023] Open
Abstract
Non-absorbable small-molecule drugs targeted to the gut represent an alternative approach to safe, non-systemic therapeutics. Such drugs remain confined to the gastrointestinal tract upon oral dosing by virtue of their limited passive permeability, increasing the local concentration at the site of action while minimizing exposure elsewhere in the body. Herein we review the latest advances in the field of gut-restricted therapeutics, highlighting the different strategies and tactics that medicinal chemists have employed in pursuit of drugs with minimal intestinal absorption.
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Affiliation(s)
- Ruth Dorel
- Genentech, Inc., South San Francisco, California 94080, United States
| | - Alice R. Wong
- Genentech, Inc., South San Francisco, California 94080, United States
| | - James J. Crawford
- Genentech, Inc., South San Francisco, California 94080, United States
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8
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Wang Z, Qiang X, Peng Y, Wang Y, Zhao Q, He D. Design and synthesis of bile acid derivatives and their activity against colon cancer. RSC Med Chem 2022; 13:1391-1409. [PMID: 36439975 PMCID: PMC9667766 DOI: 10.1039/d2md00220e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/18/2022] [Indexed: 08/21/2023] Open
Abstract
Bile acids (BAs) containing both hydrophilic hydroxyl and carboxyl groups and hydrophobic methyl and steroid nuclei can promote the absorption of fat and other substances in the intestine, and they are synthesized by cholesterol in the liver and then returned to the liver through enteric liver circulation. Because there are many BA receptors on the cell membrane of colon tissues, BAs can improve the specific delivery and transport of medicines to colon tissues. Moreover, BAs have a certain anticancer and inflammation activity by themselves. Based on this theory, a series of BA derivatives against colon cancer including cholic acid (CA), chenodeoxycholic acid (CDCA), ursodeoxycholic acid (UDCA) and lithocholic acid (LCA) were designed and synthesized, and their antitumor activity was evaluated. For in vitro anti-tumor tests, all the compounds displayed cell proliferative inhibition to nine human malignant tumor cell lines to some degree, and in particular they showed stronger inhibition to the colon cancer cells than the other cell lines. Among them, four compounds (4, 5, 6, and 7) showed stronger activity than the other compounds as well as the positive control 5-FU against HCT116 cells, and their IC50 was between 21.32 μmol L-1 and 28.90 μmol L-1; cell clone formation and migration tests showed that they not only effectively inhibited the formation of HCT116 cell colonies, but also inhibited the HCT116 cell migration and invasion; moreover, they induced apoptosis, arrested the mitotic process at the G2/M phase of the cell cycle, reduced the mitochondrial membrane potential, increased the intracellular ROS levels, and reduced the expression of Bcl-2 and p-STAT3 in HCT 116 cells. In addition, they also displayed intermediate anti-inflammatory activity by inhibiting inflammatory mediators NO and downregulating TNF-α expression, which also is one of the causes of colon cancer. This suggests that they deserve to be further investigated as candidates for colon cancer treatment drugs.
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Affiliation(s)
- Zongyuan Wang
- Materia Medica Development Group, Institute of Medicinal Chemistry, School of Pharmacy of Lanzhou University Lanzhou 730000 China +869318915686 +869318915686
| | - Xin Qiang
- Materia Medica Development Group, Institute of Medicinal Chemistry, School of Pharmacy of Lanzhou University Lanzhou 730000 China +869318915686 +869318915686
| | - Yijie Peng
- Materia Medica Development Group, Institute of Medicinal Chemistry, School of Pharmacy of Lanzhou University Lanzhou 730000 China +869318915686 +869318915686
| | - Yanni Wang
- Materia Medica Development Group, Institute of Medicinal Chemistry, School of Pharmacy of Lanzhou University Lanzhou 730000 China +869318915686 +869318915686
| | - Quanyi Zhao
- Materia Medica Development Group, Institute of Medicinal Chemistry, School of Pharmacy of Lanzhou University Lanzhou 730000 China +869318915686 +869318915686
| | - Dian He
- Materia Medica Development Group, Institute of Medicinal Chemistry, School of Pharmacy of Lanzhou University Lanzhou 730000 China +869318915686 +869318915686
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Abstract
The nosocomial pathogen Clostridioides difficile is a burden to the healthcare system. Gut microbiome disruption, most commonly by broad-spectrum antibiotic treatment, is well established to generate a state that is susceptible to CDI. A variety of metabolites produced by the host and/or gut microbiota have been shown to interact with C. difficile. Certain bile acids promote/inhibit germination while other cholesterol-derived compounds and amino acids used in the Stickland metabolic pathway affect growth and CDI colonization. Short chain fatty acids maintain intestinal barrier integrity and a myriad of other metabolic compounds are used as nutritional sources or used by C. difficile to inhibit or outcompete other bacteria in the gut. As the move toward non-antibiotic CDI treatment takes place, a deeper understanding of interactions between C. difficile and the host's gut microbiome and metabolites becomes more relevant.
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Affiliation(s)
| | - Joseph A. Sorg
- Department of Biology, Texas A&M University, College Station, TX, USA,CONTACT Joseph A. Sorg Department of Biology, Texas A&M University, College Station, TX77843, USA
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Chen J, Du Y, Lu Y, Wang H, Wu Q. Recent development of small-molecular inhibitors against Clostridioides difficile infection. Bioorg Chem 2022; 125:105843. [DOI: 10.1016/j.bioorg.2022.105843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 03/02/2022] [Accepted: 04/23/2022] [Indexed: 11/29/2022]
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Discovery of novel cholic acid derivatives as highly potent agonists for G protein-coupled bile acid receptor. Bioorg Chem 2021; 120:105588. [PMID: 34979448 DOI: 10.1016/j.bioorg.2021.105588] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 11/15/2021] [Accepted: 12/26/2021] [Indexed: 11/20/2022]
Abstract
In this study, fourteen new cholic acid (CA) derivatives were designed and synthesized, and the GloSensor cAMP accumulation assay indicated that all derivatives could activate the Takeda G protein-coupled receptor 5 (TGR5). Methylation of 7- and 12-hydroxyl groups in CA significantly increased TGR5 agonism for the new derivatives. For example, 7,12-dimethoxy derivative B1 exhibited 78-fold higher potency for TGR5 than the 7,12-dihydroxyl derivative A1 and 258-fold higher potency than CA itself. On the other hand, A1 positively modulated chenodeoxycholic acid (CDCA) functional activity in TGR5, whereas B1 did not show similar activity. Molecular docking experiments indicated that A1 formed a hydrogen bond between the 12-OH and amino acid Thr131 of TGR5, which is significant for its allosteric property. However, methylation at the 12-hydroxyl group in CA (derivative B1) disrupted this pivotal H-bond. Therefore, the free 12-hydroxyl group is essential for the CA derivatives in TGR5 allosteric agonism. Overall, we discovered a highly potent TGR5 agonist, B1, which can be used as lead compound for further study.
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12
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Sharma SK, Yip C, Simon MP, Phan J, Abel-Santos E, Firestine SM. Studies on the Importance of the 7α-, and 12α- hydroxyl groups of N-Aryl-3α,7α,12α-trihydroxy-5β-cholan-24-amides on their Antigermination Activity Against a Hypervirulent Strain of Clostridioides (Clostridium) difficile. Bioorg Med Chem 2021; 52:116503. [PMID: 34837818 DOI: 10.1016/j.bmc.2021.116503] [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: 08/10/2021] [Revised: 10/19/2021] [Accepted: 11/02/2021] [Indexed: 10/19/2022]
Abstract
Chenodeoxycholic acid (CDCA) is a natural germination inhibitor for C. difficile spores. In our previous study (J. Med. Chem., 2018, 61, 6759-6778), we identified N-phenyl-3α,7α,12α-trihydroxy-5β-cholan-24-amide as an inhibitor of C. difficile strain R20291 with an IC50 of 1.8 μM. Studies of bile salts on spore germination have shown that chenodeoxycholate, ursodeoxycholate and lithocholate are more potent inhibitors of germination compared to cholate. Given this, we created amide analogs of chenodeoxycholic, deoxycholic, lithocholic and ursodeoxycholic acids using amines identified from our previous studies. We found that chenodeoxy- and deoxycholate derivatives were active with potencies equivalent to those for cholanamides. This indicates that only 2 out of the 3 hydroxyl groups are needed for activity and that the alpha stereochemistry at position 7 is required for inhibition of spore germination.
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Affiliation(s)
- Shiv K Sharma
- Department of Pharmaceutical sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI 48201, United States
| | - Christopher Yip
- Department of Chemistry and Biochemistry, University of Nevada at Las Vegas, 4505 S. Maryland Pkwy., Las Vegas, NV, 89154, United States
| | - Matthew P Simon
- Department of Pharmaceutical sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI 48201, United States
| | - Jacqueline Phan
- Department of Chemistry and Biochemistry, University of Nevada at Las Vegas, 4505 S. Maryland Pkwy., Las Vegas, NV, 89154, United States
| | - Ernesto Abel-Santos
- Department of Chemistry and Biochemistry, University of Nevada at Las Vegas, 4505 S. Maryland Pkwy., Las Vegas, NV, 89154, United States
| | - Steven M Firestine
- Department of Pharmaceutical sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI 48201, United States.
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13
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Škorić DĐ, Klisurić OR, Jakimov DS, Sakač MN, Csanádi JJ. Synthesis of new bile acid-fused tetrazoles using the Schmidt reaction. Beilstein J Org Chem 2021; 17:2611-2620. [PMID: 34760027 PMCID: PMC8551880 DOI: 10.3762/bjoc.17.174] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 10/05/2021] [Indexed: 12/11/2022] Open
Abstract
A practical and high-yielding Schmidt reaction for the synthesis of fused tetrazoles from bile acid precursors was developed. Mild reaction conditions using TMSN3 instead of hydrazoic acid as an azide source produced good yields of the desired tetrazoles. These conditions could be applied to other steroidal precursors. Additionally, an improved methodology for the synthesis of different ketone and enone precursors from cholic acid, deoxycholic acid, and chenodeoxycholic acid was established. Newly obtained tetrazole derivatives were characterized by NMR and X-ray diffraction spectroscopy. In a number of cases, preliminary antiproliferative tests of new compounds showed strong and selective activity towards certain tumor cell lines.
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Affiliation(s)
- Dušan Đ Škorić
- Department of Chemistry, Biochemistry and Environmental Protection, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 3, 21000 Novi Sad, Serbia
| | - Olivera R Klisurić
- Department of Physics, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 4, 21000 Novi Sad, Serbia
| | - Dimitar S Jakimov
- Oncology Institute of Vojvodina, Faculty of Medicine, University of Novi Sad, Put Dr Goldmana 4, 21204 Sremska Kamenica, Serbia
| | - Marija N Sakač
- Department of Chemistry, Biochemistry and Environmental Protection, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 3, 21000 Novi Sad, Serbia
| | - János J Csanádi
- Department of Chemistry, Biochemistry and Environmental Protection, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 3, 21000 Novi Sad, Serbia
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Monaghan TM, Seekatz AM, Mullish BH, Moore-Gillon CCER, Dawson LF, Ahmed A, Kao D, Chan WC. Clostridioides difficile: innovations in target discovery and potential for therapeutic success. Expert Opin Ther Targets 2021; 25:949-963. [PMID: 34793686 DOI: 10.1080/14728222.2021.2008907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 11/17/2021] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Clostridioides difficile infection (CDI) remains a worldwide clinical problem. Increased incidence of primary infection, occurrence of hypertoxigenic ribotypes, and more frequent occurrence of drug resistant, recurrent, and non-hospital CDI, emphasizes the urgent unmet need of discovering new therapeutic targets. AREAS COVERED We searched PubMed and Web of Science databases for articles identifying novel therapeutic targets or treatments for C. difficile from 2001 to 2021. We present an updated review on current preclinical efforts on designing inhibitory compounds against these drug targets and indicate how these could become the focus of future therapeutic approaches. We also evaluate the increasing exploitability of gut microbial-derived metabolites and host-derived therapeutics targeting VEGF-A, immune targets and pathways, ion transporters, and microRNAs as anti-C. difficile therapeutics, which have yet to reach clinical trials. Our review also highlights the therapeutic potential of re-purposing currently available agents . We conclude by considering translational hurdles and possible strategies to mitigate these problems. EXPERT OPINION Considerable progress has been made in the development of new anti-CDI drug candidates. Nevertheless, a greater comprehension of CDI pathogenesis and host-microbe interactions is beginning to uncover potential novel therapeutic targets, which can be exploited to plug gaps in the CDI drug discovery pipeline.
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Affiliation(s)
- Tanya M Monaghan
- NIHR Nottingham Biomedical Research Centre, University of Nottingham, Nottingham, UK
- Nottingham Digestive Diseases Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Anna M Seekatz
- Biological Sciences, Clemson University, Clemson, SC, USA
| | - Benjamin H Mullish
- Division of Digestive Diseases, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, UK
- Departments of Gastroenterology and Hepatology, St Mary's Hospital, Imperial College Healthcare NHS Trust, London, UK
| | - Claudia C E R Moore-Gillon
- Division of Digestive Diseases, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, UK
- Departments of Gastroenterology and Hepatology, St Mary's Hospital, Imperial College Healthcare NHS Trust, London, UK
| | - Lisa F Dawson
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Ammar Ahmed
- NIHR Nottingham Biomedical Research Centre, University of Nottingham, Nottingham, UK
- Nottingham Digestive Diseases Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Dina Kao
- Department of Gastroenterology, Zeidler Ledcor Centre, University of Alberta, Edmonton, Alberta, Canada
| | - Weng C Chan
- School of Pharmacy, Biodiscovery Institute, University of Nottingham, University Park, Nottingham, UK
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15
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Opportunities for Nanomedicine in Clostridioides difficile Infection. Antibiotics (Basel) 2021; 10:antibiotics10080948. [PMID: 34438998 PMCID: PMC8388953 DOI: 10.3390/antibiotics10080948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/30/2021] [Accepted: 08/03/2021] [Indexed: 12/19/2022] Open
Abstract
Clostridioides difficile, a spore-forming bacterium, is a nosocomial infectious pathogen which can be found in animals as well. Although various antibiotics and disinfectants were developed, C. difficile infection (CDI) remains a serious health problem. C. difficile spores have complex structures and dormant characteristics that contribute to their resistance to harsh environments, successful transmission and recurrence. C. difficile spores can germinate quickly after being exposed to bile acid and co-germinant in a suitable environment. The vegetative cells produce endospores, and the mature spores are released from the hosts for dissemination of the pathogen. Therefore, concurrent elimination of C. difficile vegetative cells and inhibition of spore germination is essential for effective control of CDI. This review focused on the molecular pathogenesis of CDI and new trends in targeting both spores and vegetative cells of this pathogen, as well as the potential contribution of nanotechnologies for the effective management of CDI.
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16
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Shen A. Clostridioides difficile Spore Formation and Germination: New Insights and Opportunities for Intervention. Annu Rev Microbiol 2021; 74:545-566. [PMID: 32905755 DOI: 10.1146/annurev-micro-011320-011321] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Spore formation and germination are essential for the bacterial pathogen Clostridioides difficile to transmit infection. Despite the importance of these developmental processes to the infection cycle of C. difficile, the molecular mechanisms underlying how this obligate anaerobe forms infectious spores and how these spores germinate to initiate infection were largely unknown until recently. Work in the last decade has revealed that C. difficile uses a distinct mechanism for sensing and transducing germinant signals relative to previously characterized spore formers. The C. difficile spore assembly pathway also exhibits notable differences relative to Bacillus spp., where spore formation has been more extensively studied. For both these processes, factors that are conserved only in C. difficile or the related Peptostreptococcaceae family are employed, and even highly conserved spore proteins can have differential functions or requirements in C. difficile compared to other spore formers. This review summarizes our current understanding of the mechanisms controlling C. difficile spore formation and germination and describes strategies for inhibiting these processes to prevent C. difficile infection and disease recurrence.
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Affiliation(s)
- Aimee Shen
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA;
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17
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Gao C, Chen X, Yu L, Jiang L, Pan D, Jiang S, Gan Y, Liu Y, Yi X. New 24-Membered Macrolactins Isolated from Marine Bacteria Bacillus siamensis as Potent Fungal Inhibitors against Sugarcane Smut. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:4392-4401. [PMID: 33834775 DOI: 10.1021/acs.jafc.0c07415] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Sugarcane smut, caused by Sporisorium scitamineum, is one of the most devastating fungal diseases affecting sugarcane worldwide. To develop a potent sugarcane smut fungicide, secondary metabolites of marine-derived Bacillus siamensis were isolated and screened for inhibitory activities, which led to the discovery of five new 24-membered macrolactins, bamemacrolactins A-E (1-5), with 3 being the most potent inhibitor. The antifungal mechanism of 3 was studied by assessing its effects on mycelial morphology and the cell wall. Differential proteomics were used to analyze proteins in S. scitamineum upon treatment with bamemacrolactin C and to elucidate its antifungal mechanism. A total of 533 differentially expressed proteins were found. After the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses, eight target proteins were selected, and their functions were discussed. Six of the eight proteins were reported as antifungal targets. The target proteins are involved in the oxidative phosphorylation pathway. Therefore, the potent inhibition of S. scitamineum by compound 3 is most likely through oxidative phosphorylation and targeting a series of enzymes.
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Affiliation(s)
- Chenghai Gao
- Institute of Marine Drugs, School of Pharmaceutical Sciences, Guangxi Key Laboratory of Efficacy Study on Chinese Materia Medica, Guangxi University of Chinese Medicine, NO. 13 Wuhe Rood, Nanning 530200, China
| | - Xianqiang Chen
- Institute of Marine Drugs, School of Pharmaceutical Sciences, Guangxi Key Laboratory of Efficacy Study on Chinese Materia Medica, Guangxi University of Chinese Medicine, NO. 13 Wuhe Rood, Nanning 530200, China
| | - Lian Yu
- Institute of Marine Drugs, School of Pharmaceutical Sciences, Guangxi Key Laboratory of Efficacy Study on Chinese Materia Medica, Guangxi University of Chinese Medicine, NO. 13 Wuhe Rood, Nanning 530200, China
| | - Lei Jiang
- Institute of Marine Drugs, School of Pharmaceutical Sciences, Guangxi Key Laboratory of Efficacy Study on Chinese Materia Medica, Guangxi University of Chinese Medicine, NO. 13 Wuhe Rood, Nanning 530200, China
| | - Dongjin Pan
- Institute of Marine Drugs, School of Pharmaceutical Sciences, Guangxi Key Laboratory of Efficacy Study on Chinese Materia Medica, Guangxi University of Chinese Medicine, NO. 13 Wuhe Rood, Nanning 530200, China
| | - Shu Jiang
- Institute of Marine Drugs, School of Pharmaceutical Sciences, Guangxi Key Laboratory of Efficacy Study on Chinese Materia Medica, Guangxi University of Chinese Medicine, NO. 13 Wuhe Rood, Nanning 530200, China
| | - Yuman Gan
- Institute of Marine Drugs, School of Pharmaceutical Sciences, Guangxi Key Laboratory of Efficacy Study on Chinese Materia Medica, Guangxi University of Chinese Medicine, NO. 13 Wuhe Rood, Nanning 530200, China
| | - Yonghong Liu
- Institute of Marine Drugs, School of Pharmaceutical Sciences, Guangxi Key Laboratory of Efficacy Study on Chinese Materia Medica, Guangxi University of Chinese Medicine, NO. 13 Wuhe Rood, Nanning 530200, China
| | - Xiangxi Yi
- Institute of Marine Drugs, School of Pharmaceutical Sciences, Guangxi Key Laboratory of Efficacy Study on Chinese Materia Medica, Guangxi University of Chinese Medicine, NO. 13 Wuhe Rood, Nanning 530200, China
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18
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Nakhi A, Wong HL, Weldy M, Khoruts A, Sadowsky MJ, Dosa PI. Structural modifications that increase gut restriction of bile acid derivatives. RSC Med Chem 2021; 12:394-405. [PMID: 34046622 DOI: 10.1039/d0md00425a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 01/30/2021] [Indexed: 11/21/2022] Open
Abstract
Bile acid derivatives have been investigated as possible therapeutics for a wide array of conditions, including several for which gut-restricted analogs would likely be preferred. These include the prevention of Clostridioides difficile infection (CDI) and the treatment of inflammatory bowel disease (IBD). The design of gut-restricted bile acid analogs, however, is complicated by the highly efficient enterohepatic circulation system that typically reabsorbs these compounds from the digestive tract for subsequent return to the liver. Herein, we report that incorporation of a sulfate group at the 7-position of the bile acid scaffold reduces oral bioavailability and increases fecal recovery in two pairs of compounds designed to inhibit the germination of C. difficile spores. A different approach was necessary for designing gut-restricted bile acid-based TGR5 agonists for the treatment of IBD, as the incorporation of a 7-sulfate group reduces activity at this receptor. Instead, building on our previous discovery that incorporation of a 7-methoxy group into chenodeoxycholic acid derivatives greatly increases their TGR5 receptor potency, we determined that an N-methyl-d-glucamine group could be conjugated to the scaffold to obtain a compound with an excellent mix of potency at the TGR5 receptor, low oral exposure, and good fecal recovery.
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Affiliation(s)
- Ali Nakhi
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota 717 Delaware Street SE Minneapolis Minnesota 55414 USA +1 612 626 6318 +1 612 625 7948
| | - Henry L Wong
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota 717 Delaware Street SE Minneapolis Minnesota 55414 USA +1 612 626 6318 +1 612 625 7948
| | - Melissa Weldy
- BioTechnology Institute, University of Minnesota 1479 Gortner Avenue St. Paul Minnesota 55108 USA.,Department of Medicine, Division of Gastroenterology, University of Minnesota Minneapolis Minnesota 55414 USA
| | - Alexander Khoruts
- BioTechnology Institute, University of Minnesota 1479 Gortner Avenue St. Paul Minnesota 55108 USA.,Department of Medicine, Division of Gastroenterology, University of Minnesota Minneapolis Minnesota 55414 USA.,Center for Immunology, University of Minnesota Minneapolis Minnesota 55414 USA
| | - Michael J Sadowsky
- BioTechnology Institute, University of Minnesota 1479 Gortner Avenue St. Paul Minnesota 55108 USA.,Department of Soil, Water & Climate, Department of Plant and Microbial Biology, University of Minnesota St. Paul Minnesota USA
| | - Peter I Dosa
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota 717 Delaware Street SE Minneapolis Minnesota 55414 USA +1 612 626 6318 +1 612 625 7948
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19
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Yip C, Okada NC, Howerton A, Amei A, Abel-Santos E. Pharmacokinetics of CamSA, a potential prophylactic compound against Clostridioides difficile infections. Biochem Pharmacol 2021; 183:114314. [PMID: 33152344 PMCID: PMC7770080 DOI: 10.1016/j.bcp.2020.114314] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/28/2020] [Accepted: 10/29/2020] [Indexed: 12/30/2022]
Abstract
Clostridioides difficile infections (CDI) are the leading cause of nosocomial antibiotic-associated diarrhea. C. difficile produces dormant spores that serve as infectious agents. Bile salts in the gastrointestinal tract signal spores to germinate into toxin-producing cells. As spore germination is required for CDI onset, anti-germination compounds may serve as prophylactics. CamSA, a synthetic bile salt, was previously shown to inhibit C. difficile spore germination in vitro and in vivo. Unexpectedly, a single dose of CamSA was sufficient to offer multi-day protection from CDI in mice without any observable toxicity. To study this intriguing protection pattern, we examined the pharmacokinetic parameters of CamSA. CamSA was stable to the gut of antibiotic-treated mice but was extensively degraded by the microbiota of non-antibiotic-treated animals. Our data also suggest that CamSA's systemic absorption is minimal since it is retained primarily in the intestinal lumen and liver. CamSA shows weak interactions with CYP3A4, a P450 hepatic isozyme involved in drug metabolism and bile salt modification. Like other bile salts, CamSA seems to undergo enterohepatic circulation. We hypothesize that the cycling of CamSA between the liver and intestines serves as a slow-release mechanism that allows CamSA to be retained in the gastrointestinal tract for days. This model explains how a single CamSA dose can prevent murine CDI even though spores are present in the animal's intestine for up to four days post-challenge.
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Affiliation(s)
- Christopher Yip
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, Nevada 89154, United States
| | - Naomi C Okada
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, Nevada 89154, United States
| | - Amber Howerton
- Department of Physical and Life Sciences, Nevada State College, 1300 Nevada State Drive, Henderson, Nevada, 89002, United States
| | - Amei Amei
- Department of Mathematical Sciences, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, Nevada 89154, United States
| | - Ernesto Abel-Santos
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, Nevada 89154, United States.
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20
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The Great ESKAPE: Exploring the Crossroads of Bile and Antibiotic Resistance in Bacterial Pathogens. Infect Immun 2020; 88:IAI.00865-19. [PMID: 32661122 DOI: 10.1128/iai.00865-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Throughout the course of infection, many pathogens encounter bactericidal conditions that threaten the viability of the bacteria and impede the establishment of infection. Bile is one of the most innately bactericidal compounds present in humans, functioning to reduce the bacterial burden in the gastrointestinal tract while also aiding in digestion. It is becoming increasingly apparent that pathogens successfully resist the bactericidal conditions of bile, including bacteria that do not normally cause gastrointestinal infections. This review highlights the ability of Enterococcus, Staphylococcus, Klebsiella, Acinetobacter, Pseudomonas, Enterobacter (ESKAPE), and other enteric pathogens to resist bile and how these interactions can impact the sensitivity of bacteria to various antimicrobial agents. Given that pathogen exposure to bile is an essential component to gastrointestinal transit that cannot be avoided, understanding how bile resistance mechanisms align with antimicrobial resistance is vital to our ability to develop new, successful therapeutics in an age of widespread and increasing antimicrobial resistance.
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21
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Abstract
There are ten good reasons why it is important to think about abnormalities in bile acid control in inflammatory bowel disease. Before reviewing these reasons, it is relevant to review essential elements in the enterohepatic circulation, synthesis and actions of bile acids.
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Affiliation(s)
- Michael Camilleri
- Clinical Enteric Neuroscience Translational and Epidemiological Research (CENTER), Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA,Corresponding author: Michael Camilleri, MD, Mayo Clinic, Charlton 8–110, 200 First St. S.W., Rochester, MN 55905, USA. Tel: 507-266-2305;
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22
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Shen A. Clostridioides difficile Spores: Bile Acid Sensors and Trojan Horses of Transmission. Clin Colon Rectal Surg 2020; 33:58-66. [PMID: 32104157 DOI: 10.1055/s-0040-1701230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The Gram-positive, spore-forming bacterium, Clostridioides difficile is the leading cause of healthcare-associated infections in the United States, although it also causes a significant number of community-acquired infections. C. difficile infections, which range in severity from mild diarrhea to toxic megacolon, cost more to treat than matched infections, with an annual treatment cost of approximately $6 billion for almost half-a-million infections. These high-treatment costs are due to the high rates of C. difficile disease recurrence (>20%) and necessity for special disinfection measures. These complications arise in part because C. difficile makes metabolically dormant spores, which are the major infectious particle of this obligate anaerobe. These seemingly inanimate life forms are inert to antibiotics, resistant to commonly used disinfectants, readily disseminated, and capable of surviving in the environment for a long period of time. However, upon sensing specific bile salts in the vertebrate gut, C. difficile spores transform back into the vegetative cells that are responsible for causing disease. This review discusses how spores are ideal vectors for disease transmission and how antibiotics modulate this process. We also describe the resistance properties of spores and how they create challenges eradicating spores, as well as promote their spread. Lastly, environmental reservoirs of C. difficile spores and strategies for destroying them particularly in health care environments will be discussed.
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Affiliation(s)
- Aimee Shen
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts
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23
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Neves AR, Almeida JR, Carvalhal F, Câmara A, Pereira S, Antunes J, Vasconcelos V, Pinto M, Silva ER, Sousa E, Correia-da-Silva M. Overcoming environmental problems of biocides: Synthetic bile acid derivatives as a sustainable alternative. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 187:109812. [PMID: 31669574 DOI: 10.1016/j.ecoenv.2019.109812] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 10/10/2019] [Accepted: 10/12/2019] [Indexed: 06/10/2023]
Abstract
Marine biofouling represents a global economic and ecological challenge. Some marine organisms produce bioactive metabolites, such as steroids, that inhibit the settlement and growth of fouling organisms. The aim of this work was to explore bile acids as a new scaffold with antifouling (AF) activity by using chemical synthesis to produce a series of bile acid derivatives with optimized AF performance and understand their structure-activity relationships. Seven bile acid derivatives were successfully synthesized in moderate to high yields, and their structures were elucidated through spectroscopic methods. Their AF activities were tested against both macro- and microfouling communities. The most potent bile acid against the settlement of Mytilus galloprovincialis larvae was the methyl ester derivative of cholic acid (10), which showed an EC50 of 3.7 μM and an LC50/EC50 > 50 (LC50 > 200 μM) in AF effectiveness vs toxicity studies. Two derivatives of deoxycholic acid (5 and 7) potently inhibited the growth of biofilm-forming marine bacteria with EC50 values < 10 μM, and five bile acids (1, 5, and 7-9) potently inhibited the growth of diatoms, showing EC50 values between 3 and 10 μM. Promising AF profiles were achieved with some of the synthesized bile acids by combining antimacrofouling and antimicrofouling activities. Initial studies on the incorporation of one of these promising bile acid derivatives in polymeric coatings, such as a marine paint, demonstrated the ability of these compounds to generate coatings with antimacrofouling activity.
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Affiliation(s)
- Ana R Neves
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General, Norton de Matos S/N, 4450-208, Matosinhos, Portugal; Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal
| | - Joana R Almeida
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General, Norton de Matos S/N, 4450-208, Matosinhos, Portugal
| | - Francisca Carvalhal
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General, Norton de Matos S/N, 4450-208, Matosinhos, Portugal; Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal
| | - Amadeu Câmara
- Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal
| | - Sandra Pereira
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General, Norton de Matos S/N, 4450-208, Matosinhos, Portugal
| | - Jorge Antunes
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General, Norton de Matos S/N, 4450-208, Matosinhos, Portugal; Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4069-007, Porto, Portugal
| | - Vitor Vasconcelos
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General, Norton de Matos S/N, 4450-208, Matosinhos, Portugal; Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4069-007, Porto, Portugal
| | - Madalena Pinto
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General, Norton de Matos S/N, 4450-208, Matosinhos, Portugal; Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal
| | - Elisabete R Silva
- BioISI - Biosystems & Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande C8 bdg, Lisboa, 1749-016 Portugal; CERENA - Centro de Recursos Naturais e Ambiente, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1, 1049-001, Lisboa, Portugal
| | - Emília Sousa
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General, Norton de Matos S/N, 4450-208, Matosinhos, Portugal; Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal
| | - Marta Correia-da-Silva
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General, Norton de Matos S/N, 4450-208, Matosinhos, Portugal; Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal.
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24
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Nakhi A, McDermott CM, Stoltz KL, John K, Hawkinson JE, Ambrose EA, Khoruts A, Sadowsky MJ, Dosa PI. 7-Methylation of Chenodeoxycholic Acid Derivatives Yields a Substantial Increase in TGR5 Receptor Potency. J Med Chem 2019; 62:6824-6830. [PMID: 31268316 DOI: 10.1021/acs.jmedchem.9b00770] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
TGR5 agonists are potential therapeutics for a variety of conditions including type 2 diabetes, obesity, and inflammatory bowel disease. After screening a library of chenodeoxycholic acid (CDCA) derivatives, it was determined that a range of modifications could be made to the acid moiety of CDCA which significantly increased TGR5 agonist potency. Surprisingly, methylation of the 7-hydroxyl of CDCA led to a further dramatic increase in potency, allowing the identification of 5.6 nM TGR5 agonist 17.
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Affiliation(s)
- Ali Nakhi
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry , University of Minnesota , 717 Delaware Street SE , Minneapolis , Minnesota 55414 , United States
| | - Connor M McDermott
- Department of Medicinal Chemistry , University of Minnesota , 717 Delaware Street SE , Minneapolis , Minnesota 55414 , United States
| | - Kristen L Stoltz
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry , University of Minnesota , 717 Delaware Street SE , Minneapolis , Minnesota 55414 , United States
| | - Kristen John
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry , University of Minnesota , 717 Delaware Street SE , Minneapolis , Minnesota 55414 , United States
| | - Jon E Hawkinson
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry , University of Minnesota , 717 Delaware Street SE , Minneapolis , Minnesota 55414 , United States
| | - Elizabeth A Ambrose
- Department of Medicinal Chemistry , University of Minnesota , 717 Delaware Street SE , Minneapolis , Minnesota 55414 , United States
| | - Alexander Khoruts
- Center for Immunology, Department of Medicine, Division of Gastroenterology , University of Minnesota , Minneapolis , Minnesota 55414 , United States.,BioTechnology Institute, Department of Soil, Water & Climate, and Department of Plant and Microbial Biology , University of Minnesota , St. Paul , Minnesota 55108 , United States
| | - Michael J Sadowsky
- BioTechnology Institute, Department of Soil, Water & Climate, and Department of Plant and Microbial Biology , University of Minnesota , St. Paul , Minnesota 55108 , United States
| | - Peter I Dosa
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry , University of Minnesota , 717 Delaware Street SE , Minneapolis , Minnesota 55414 , United States
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25
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Hegyi P, Maléth J, Walters JR, Hofmann AF, Keely SJ. Guts and Gall: Bile Acids in Regulation of Intestinal Epithelial Function in Health and Disease. Physiol Rev 2019; 98:1983-2023. [PMID: 30067158 DOI: 10.1152/physrev.00054.2017] [Citation(s) in RCA: 164] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Epithelial cells line the entire surface of the gastrointestinal tract and its accessory organs where they primarily function in transporting digestive enzymes, nutrients, electrolytes, and fluid to and from the luminal contents. At the same time, epithelial cells are responsible for forming a physical and biochemical barrier that prevents the entry into the body of harmful agents, such as bacteria and their toxins. Dysregulation of epithelial transport and barrier function is associated with the pathogenesis of a number of conditions throughout the intestine, such as inflammatory bowel disease, chronic diarrhea, pancreatitis, reflux esophagitis, and cancer. Driven by discovery of specific receptors on intestinal epithelial cells, new insights into mechanisms that control their synthesis and enterohepatic circulation, and a growing appreciation of their roles as bioactive bacterial metabolites, bile acids are currently receiving a great deal of interest as critical regulators of epithelial function in health and disease. This review aims to summarize recent advances in this field and to highlight how bile acids are now emerging as exciting new targets for disease intervention.
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Affiliation(s)
- Peter Hegyi
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
| | - Joszef Maléth
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
| | - Julian R Walters
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
| | - Alan F Hofmann
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
| | - Stephen J Keely
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
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26
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Sharma SK, Yip C, Esposito EX, Sharma PV, Simon MP, Abel-Santos E, Firestine SM. The Design, Synthesis, and Characterizations of Spore Germination Inhibitors Effective against an Epidemic Strain of Clostridium difficile. J Med Chem 2018; 61:6759-6778. [PMID: 30004695 DOI: 10.1021/acs.jmedchem.8b00632] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Clostridium difficile infections (CDI), particularly those caused by the BI/NAP1/027 epidemic strains, are challenging to treat. One method to address this disease is to prevent the development of CDI by inhibiting the germination of C. difficile spores. Previous studies have identified cholic amide m-sulfonic acid, CamSA, as an inhibitor of spore germination. However, CamSA is inactive against the hypervirulent strain R20291. To circumvent this problem, a series of cholic acid amides were synthesized and tested against R20291. The best compound in the series was the simple phenyl amide analogue which possessed an IC50 value of 1.8 μM, more than 225 times as potent as the natural germination inhibitor, chenodeoxycholate. This is the most potent inhibitor of C. difficile spore germination described to date. QSAR and molecular modeling analysis demonstrated that increases in hydrophobicity and decreases in partial charge or polar surface area were correlated with increases in potency.
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Affiliation(s)
- Shiv K Sharma
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences , Wayne State University , 259 Mack Avenue , Detroit , Michigan 48201 , United States
| | - Christopher Yip
- Department of Chemistry and Biochemistry , University of Nevada at Las Vegas , 4505 South Maryland Parkway , Las Vegas , Nevada 89154 , United States
| | | | - Prateek V Sharma
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences , Wayne State University , 259 Mack Avenue , Detroit , Michigan 48201 , United States
| | - Matthew P Simon
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences , Wayne State University , 259 Mack Avenue , Detroit , Michigan 48201 , United States
| | - Ernesto Abel-Santos
- Department of Chemistry and Biochemistry , University of Nevada at Las Vegas , 4505 South Maryland Parkway , Las Vegas , Nevada 89154 , United States
| | - Steven M Firestine
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences , Wayne State University , 259 Mack Avenue , Detroit , Michigan 48201 , United States
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27
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Mitachi K, Yun HG, Kurosu SM, Eslamimehr S, Lemieux MR, Klaić L, Clemons WM, Kurosu M. Novel FR-900493 Analogues That Inhibit the Outgrowth of Clostridium difficile Spores. ACS OMEGA 2018; 3:1726-1739. [PMID: 29503973 PMCID: PMC5830699 DOI: 10.1021/acsomega.7b01740] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 01/26/2018] [Indexed: 05/08/2023]
Abstract
The spectrum of antibacterial activity for the nucleoside antibiotic FR-900493 (1) can be extended by chemical modifications. We have generated a small focused library based on the structure of 1 and identified UT-17415 (9), UT-17455 (10), UT-17460 (11), and UT-17465 (12), which exhibit anti-Clostridium difficile growth inhibitory activity. These analogues also inhibit the outgrowth of C. difficile spores at 2× minimum inhibitory concentration. One of these analogues, 11, relative to 1 exhibits over 180-fold and 15-fold greater activity against the enzymes, phospho-MurNAc-pentapeptide translocase (MraY) and polyprenyl phosphate-GlcNAc-1-phosphate transferase (WecA), respectively. The phosphotransferase inhibitor 11 displays antimicrobial activity against several tested bacteria including Bacillus subtilis, Clostridium spp., and Mycobacterium smegmatis, but no growth inhibitory activity is observed against the other Gram-positive and Gram-negative bacteria. The selectivity index (Vero cell cytotoxicity/C. difficileantimicrobial activity) of 11 is approximately 17, and 11 does not induce hemolysis even at a 100 μM concentration.
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Affiliation(s)
- Katsuhiko Mitachi
- Department
of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, Tennessee 38163, United States
| | - Hyun Gi Yun
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, 1200 E. California Blvd, Pasadena, California 91125, United States
| | - Sara M. Kurosu
- Department
of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, Tennessee 38163, United States
| | - Shakiba Eslamimehr
- Department
of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, Tennessee 38163, United States
| | - Maddie R. Lemieux
- Department
of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, Tennessee 38163, United States
| | - Lada Klaić
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, 1200 E. California Blvd, Pasadena, California 91125, United States
| | - William M. Clemons
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, 1200 E. California Blvd, Pasadena, California 91125, United States
| | - Michio Kurosu
- Department
of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, Tennessee 38163, United States
- E-mail: . Phone: 901-448-1045. Fax: 901-448-6940 (M.K.)
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28
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Zhu D, Sorg JA, Sun X. Clostridioides difficile Biology: Sporulation, Germination, and Corresponding Therapies for C. difficile Infection. Front Cell Infect Microbiol 2018; 8:29. [PMID: 29473021 PMCID: PMC5809512 DOI: 10.3389/fcimb.2018.00029] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 01/23/2018] [Indexed: 12/18/2022] Open
Abstract
Clostridioides difficile is a Gram-positive, spore-forming, toxin-producing anaerobe, and an important nosocomial pathogen. Due to the strictly anaerobic nature of the vegetative form, spores are the main morphotype of infection and transmission of the disease. Spore formation and their subsequent germination play critical roles in C. difficile infection (CDI) progress. Under suitable conditions, C. difficile spores will germinate and outgrow to produce the pathogenic vegetative form. During CDI, C. difficile produces toxins (TcdA and TcdB) that are required to initiate the disease. Meanwhile, it also produces spores that are responsible for the persistence and recurrence of C. difficile in patients. Recent studies have shed light on the regulatory mechanisms of C. difficile sporulation and germination. This review is to summarize recent advances on the regulation of sporulation/germination in C. difficile and the corresponding therapeutic strategies that are aimed at these important processes.
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Affiliation(s)
- Duolong Zhu
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Joseph A Sorg
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Xingmin Sun
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
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29
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Shrestha R, Sorg JA. Hierarchical recognition of amino acid co-germinants during Clostridioides difficile spore germination. Anaerobe 2018; 49:41-47. [PMID: 29221987 PMCID: PMC5844826 DOI: 10.1016/j.anaerobe.2017.12.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 11/17/2017] [Accepted: 12/03/2017] [Indexed: 12/15/2022]
Abstract
Bile acids are an important signal for germination of Clostridioides difficile spores; however, the bile acid signal alone is not sufficient. Amino acids, such as glycine, are another signal necessary for germination by C. difficile spores. Prior studies on the amino acid signal required for germination have shown that there is a preference for the amino acid used as a signal for germination. Previously we found that d-alanine can function as a co-germinant for C. difficile spores at 37 °C but not at 25 °C. Here, we tested the ability of other amino acids to act as co-germinants with taurocholate (TA) at 37 °C and found that many amino acids previously categorized as non-co-germinants are co-germinants at 37 °C. Based on the EC50 values calculated for two different strains, we found that C. difficile spores recognize different amino acids with varying efficiencies. Using this data, we ranked the amino acids based on their effect on germination and found that in addition to d-alanine, other D-forms of amino acids are also used by C. difficile spores as co-germinants. Among the different types of amino acids, ones with branched chains such as valine, leucine, and isoleucine are the poorest co-germinants. However, glycine is still the most effective amino acid signal for both strains. Our results suggest that the yet-to-be-identified amino acid germinant receptor is highly promiscuous.
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Affiliation(s)
- Ritu Shrestha
- Department of Biology, Texas A&M University, College Station, TX 77843, United States
| | - Joseph A Sorg
- Department of Biology, Texas A&M University, College Station, TX 77843, United States.
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30
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Miyake M, Kohda T, Yasugi M, Sakanoue H, Hirata S. Spores of Anaerobic Bacteria: Characteristics and Behaviors during Restoration from Damaged Status. J JPN SOC FOOD SCI 2018. [DOI: 10.3136/nskkk.65.142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Masami Miyake
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University
| | - Tomoko Kohda
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University
| | - Mayo Yasugi
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University
| | - Hideyo Sakanoue
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University
| | - Shotaro Hirata
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University
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31
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Revisiting the Role of Csp Family Proteins in Regulating Clostridium difficile Spore Germination. J Bacteriol 2017; 199:JB.00266-17. [PMID: 28874406 DOI: 10.1128/jb.00266-17] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 08/23/2017] [Indexed: 02/07/2023] Open
Abstract
Clostridium difficile causes considerable health care-associated gastrointestinal disease that is transmitted by its metabolically dormant spore form. Upon entering the gut, C. difficile spores germinate and outgrow to produce vegetative cells that release disease-causing toxins. C. difficile spore germination depends on the Csp family of (pseudo)proteases and the cortex hydrolase SleC. The CspC pseudoprotease functions as a bile salt germinant receptor that activates the protease CspB, which in turn proteolytically activates the SleC zymogen. Active SleC degrades the protective cortex layer, allowing spores to outgrow and resume metabolism. We previously showed that the CspA pseudoprotease domain, which is initially produced as a fusion to CspB, controls the incorporation of the CspC germinant receptor in mature spores. However, study of the individual Csp proteins has been complicated by the polar effects of TargeTron-based gene disruption on the cspBA-cspC operon. To overcome these limitations, we have used pyrE-based allelic exchange to create individual deletions of the regions encoding CspB, CspA, CspBA, and CspC in strain 630Δerm Our results indicate that stable CspA levels in sporulating cells depend on CspB and confirm that CspA maximizes CspC incorporation into spores. Interestingly, we observed that csp and sleC mutants spontaneously germinate more frequently in 630Δerm than equivalent mutants in the JIR8094 and UK1 strain backgrounds. Analyses of this phenomenon suggest that only a subpopulation of C. difficile 630Δerm spores can spontaneously germinate, in contrast with Bacillus subtilis spores. We also show that C. difficile clinical isolates that encode truncated CspBA variants have sequencing errors that actually produce full-length CspBA.IMPORTANCEClostridium difficile is a leading cause of health care-associated infections. Initiation of C. difficile infection depends on spore germination, a process controlled by Csp family (pseudo)proteases. The CspC pseudoprotease is a germinant receptor that senses bile salts and activates the CspB protease, which activates a hydrolase required for germination. Previous work implicated the CspA pseudoprotease in controlling CspC incorporation into spores but relied on plasmid-based overexpression. Here we have used allelic exchange to study the functions of CspB and CspA. We determined that CspA production and/or stability depends on CspB and confirmed that CspA maximizes CspC incorporation into spores. Our data also suggest that a subpopulation of C. difficile spores spontaneously germinates in the absence of bile salt germinants and/or Csp proteins.
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32
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Shrestha R, Lockless SW, Sorg JA. A Clostridium difficile alanine racemase affects spore germination and accommodates serine as a substrate. J Biol Chem 2017; 292:10735-10742. [PMID: 28487371 DOI: 10.1074/jbc.m117.791749] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 05/07/2017] [Indexed: 12/18/2022] Open
Abstract
Clostridium difficile has become one of the most common bacterial pathogens in hospital-acquired infections in the United States. Although C. difficile is strictly anaerobic, it survives in aerobic environments and transmits between hosts via spores. C. difficile spore germination is triggered in response to certain bile acids and glycine. Although glycine is the most effective co-germinant, other amino acids can substitute with varying efficiencies. Of these, l-alanine is an effective co-germinant and is also a germinant for most bacterial spores. Many endospore-forming bacteria embed alanine racemases into their spore coats, and these enzymes are thought to convert the l-alanine germinant into d-alanine, a spore germination inhibitor. Although the C. difficile Alr2 racemase is the sixth most highly expressed gene during C. difficile spore formation, a previous study reported that Alr2 has little to no role in germination of C. difficile spores in rich medium. Here, we hypothesized that Alr2 could affect C. difficile l-alanine-induced spore germination in a defined medium. We found that alr2 mutant spores more readily germinate in response to l-alanine as a co-germinant. Surprisingly, d-alanine also functioned as a co-germinant. Moreover, we found that Alr2 could interconvert l- and d-serine and that Alr2 bound to l- and d-serine with ∼2-fold weaker affinity to that of l- and d-alanine. Finally, we demonstrate that l- and d-serine are also co-germinants for C. difficile spores. These results suggest that C. difficile spores can respond to a diverse set of amino acid co-germinants and reveal that Alr2 can accommodate serine as a substrate.
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Affiliation(s)
- Ritu Shrestha
- From the Department of Biology, Texas A&M University, College Station, Texas 77843
| | - Steve W Lockless
- From the Department of Biology, Texas A&M University, College Station, Texas 77843
| | - Joseph A Sorg
- From the Department of Biology, Texas A&M University, College Station, Texas 77843
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33
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Bremer E. Clostridium difficile: A bad bug goes into defensive mode. Environ Microbiol 2017; 19:2523-2528. [PMID: 28447375 DOI: 10.1111/1462-2920.13776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 04/19/2017] [Indexed: 11/26/2022]
Affiliation(s)
- Erhard Bremer
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Karl-von Frisch Str. 8, Marburg, D-35043, Germany.,LOEWE Center for Synthetic Microbiology, Philipps-University Marburg, Hans-Meerwein Str. 6, Marburg, D-35043, Germany
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