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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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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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Budi ND, Godfrey JJ, Safdar N, Shukla SK, Rose WE. Efficacy of Omadacycline or Vancomycin Combined With Germinants for Preventing Clostridioides difficile Relapse in a Murine Model. J Infect Dis 2023; 227:622-630. [PMID: 35904942 PMCID: PMC9978312 DOI: 10.1093/infdis/jiac324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 07/15/2022] [Accepted: 07/27/2022] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Clostridioides difficile infections (CDI) and recurrence (rCDI) are major health care burdens. Recurrence is likely caused by spores in the gastrointestinal tract that germinate after antibiotic therapy. This murine study explores germinant-antibiotic combinations for CDI. METHODS Previously described murine models were evaluated using C. difficile VPI 10463. The severe model compared omadacycline versus vancomycin in survival, weight loss, clinical scoring, and C. difficile toxin production. The nonsevere model compared these antibiotics with and without germinants (solution of sodium taurocholate, taurine, sodium docusate, calcium gluconate). Additionally, colon histopathology, bile acid analysis, environmental/spore shedding, and 16S sequencing was evaluated. RESULTS In the severe model, omadacycline-treated mice had 60% survival versus 13.3% with vancomycin (hazard ratio [HR], 0.327; 95% confidence interval [CI],.126-.848; P = .015) along with decreased weight loss, and disease severity. In the nonsevere model, all mice survived with antibiotic-germinant treatment versus 60% antibiotics alone (HR, 0.109; 95% CI, .02-.410; P = .001). Omadacycline resulted in less changes in bile acids and microbiota composition. Germinant-treated mice showed no signs of rCDI, spore shedding, or significant toxin production at 15 days. CONCLUSIONS In murine models of CDI, omadacycline improved survival versus vancomycin. Germinant-antibiotic combinations were more effective at preventing rCDI compared to antibiotics alone without inducing toxin production.
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Affiliation(s)
- Noah D Budi
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jared J Godfrey
- Division of Infectious Diseases, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA.,William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin, USA
| | - Nasia Safdar
- Division of Infectious Diseases, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA.,William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin, USA
| | - Sanjay K Shukla
- Center for Precision Medicine Research, Marshfield Clinic Research Institute, Marshfield, Wisconsin, USA
| | - Warren E Rose
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
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Baloh M, Sorg JA. Clostridioides difficile spore germination: initiation to DPA release. Curr Opin Microbiol 2022; 65:101-107. [PMID: 34808546 PMCID: PMC8792321 DOI: 10.1016/j.mib.2021.11.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 11/01/2021] [Accepted: 11/04/2021] [Indexed: 02/03/2023]
Abstract
Germination by Clostridioides difficile spores is an essential step in pathogenesis. Spores are metabolically dormant forms of bacteria that resist severe conditions. Work over the last 10 years has elucidated that C. difficile spores germinate thorough a novel pathway. This review summarizes our understanding of C. difficile spore germination and the factors involved in germinant recognition, cortex degradation and DPA release.
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Affiliation(s)
- Marko Baloh
- Department of Biology, Texas A&M University, College Station, TX 77843
| | - Joseph A. Sorg
- Department of Biology, Texas A&M University, College Station, TX 77843,Corresponding author: ph: 979-845-6299,
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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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An aniline-substituted bile salt analog protects both mice and hamsters from multiple Clostridioides difficile strains. Antimicrob Agents Chemother 2021; 66:e0143521. [PMID: 34780262 DOI: 10.1128/aac.01435-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clostridioides difficile infection (CDI) is the major identifiable cause of antibiotic-associated diarrhea. The emergence of hypervirulent C. difficile strains has led to increases in both hospital- and community-acquired CDI. Furthermore, CDI relapse from hypervirulent strains can reach up to 25%. Thus, standard treatments are rendered less effective, making new methods of prevention and treatment more critical. Previously, the bile salt analog CamSA was shown to inhibit spore germination in vitro and protect mice and hamsters from C. difficile strain 630. Here, we show that CamSA was less active at preventing spore germination of other C. difficile ribotypes, including the hypervirulent strain R20291. Strain-specific in vitro germination activity of CamSA correlated with its ability to prevent CDI in mice. Additional bile salt analogs were screened for in vitro germination inhibition activity against strain R20291, and the most active compounds were tested against other strains. An aniline-substituted bile salt analog, (CaPA), was found to be a better anti-germinant than CamSA against eight different C. difficile strains. In addition, CaPA was capable of reducing, delaying, or preventing murine CDI signs in all strains tested. CaPA-treated mice showed no obvious toxicity and showed minor effects on their gut microbiome. CaPA's efficacy was further confirmed by its ability to prevent CDI in hamsters infected with strain 630. These data suggest that C. difficile spores respond to germination inhibitors in a strain-dependent manner. However, careful screening can identify anti-germinants with broad CDI prophylaxis activity.
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Aguirre AM, Yalcinkaya N, Wu Q, Swennes A, Tessier ME, Roberts P, Miyajima F, Savidge T, Sorg JA. Bile acid-independent protection against Clostridioides difficile infection. PLoS Pathog 2021; 17:e1010015. [PMID: 34665847 PMCID: PMC8555850 DOI: 10.1371/journal.ppat.1010015] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 10/29/2021] [Accepted: 10/07/2021] [Indexed: 12/21/2022] Open
Abstract
Clostridioides difficile infections occur upon ecological / metabolic disruptions to the normal colonic microbiota, commonly due to broad-spectrum antibiotic use. Metabolism of bile acids through a 7α-dehydroxylation pathway found in select members of the healthy microbiota is regarded to be the protective mechanism by which C. difficile is excluded. These 7α-dehydroxylated secondary bile acids are highly toxic to C. difficile vegetative growth, and antibiotic treatment abolishes the bacteria that perform this metabolism. However, the data that supports the hypothesis that secondary bile acids protect against C. difficile infection is supported only by in vitro data and correlative studies. Here we show that bacteria that 7α-dehydroxylate primary bile acids protect against C. difficile infection in a bile acid-independent manner. We monoassociated germ-free, wildtype or Cyp8b1-/- (cholic acid-deficient) mutant mice and infected them with C. difficile spores. We show that 7α-dehydroxylation (i.e., secondary bile acid generation) is dispensable for protection against C. difficile infection and provide evidence that Stickland metabolism by these organisms consumes nutrients essential for C. difficile growth. Our findings indicate secondary bile acid production by the microbiome is a useful biomarker for a C. difficile-resistant environment but the microbiome protects against C. difficile infection in bile acid-independent mechanisms. Secondary bile acid production by the colonic microbiome strongly correlates with an environment that is resistant to C. difficile invasion. However, it remained unclear if these bile acids provided in vivo protection. Here, we show that members of the microbiome that generate secondary bile acids (e.g., C. scindens) protect against C. difficile disease independently of secondary bile acid generation. These results are important because efforts to restore colonization resistance (e.g., FMT or precision bacterial therapy) focus on restoring secondary bile acid generation. Instead, restoring the organisms that produce 5-aminovalerate or consume proline / glycine are more important.
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Affiliation(s)
- Andrea Martinez Aguirre
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
| | - Nazli Yalcinkaya
- Baylor College of Medicine & Texas Children’s Hospital, Houston, Texas, United States of America
| | - Qinglong Wu
- Baylor College of Medicine & Texas Children’s Hospital, Houston, Texas, United States of America
| | - Alton Swennes
- Baylor College of Medicine & Texas Children’s Hospital, Houston, Texas, United States of America
| | - Mary Elizabeth Tessier
- Baylor College of Medicine & Texas Children’s Hospital, Houston, Texas, United States of America
| | - Paul Roberts
- Royal Liverpool and Broadgreen University Hospitals NHS Trust, Liverpool, United Kingdom
| | - Fabio Miyajima
- Royal Liverpool and Broadgreen University Hospitals NHS Trust, Liverpool, United Kingdom
- Oswaldo Cruz Foundation, Ceara branch, Fortaleza, Brazil
| | - Tor Savidge
- Baylor College of Medicine & Texas Children’s Hospital, Houston, Texas, United States of America
| | - Joseph A. Sorg
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
- * E-mail:
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