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Author

Sridhar Mani

Bio: Sridhar Mani is an academic researcher from Albert Einstein College of Medicine. The author has contributed to research in topics: Pregnane X receptor & Nuclear receptor. The author has an hindex of 49, co-authored 169 publications receiving 8385 citations. Previous affiliations of Sridhar Mani include Montefiore Medical Center & Yeshiva University.


Papers
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Journal ArticleDOI
27 Nov 2015-Science
TL;DR: A key role is revealed for Bacteroidales in the immunostimulatory effects of CTLA-4 blockade, which is found to depend on distinct Bacteroides species in mice and patients.
Abstract: Antibodies targeting CTLA-4 have been successfully used as cancer immunotherapy. We find that the antitumor effects of CTLA-4 blockade depend on distinct Bacteroides species. In mice and patients, T cell responses specific for B. thetaiotaomicron or B. fragilis were associated with the efficacy of CTLA-4 blockade. Tumors in antibiotic-treated or germ-free mice did not respond to CTLA blockade. This defect was overcome by gavage with B. fragilis, by immunization with B. fragilis polysaccharides, or by adoptive transfer of B. fragilis–specific T cells. Fecal microbial transplantation from humans to mice confirmed that treatment of melanoma patients with antibodies against CTLA-4 favored the outgrowth of B. fragilis with anticancer properties. This study reveals a key role for Bacteroidales in the immunostimulatory effects of CTLA-4 blockade.

2,360 citations

Journal ArticleDOI
05 Nov 2010-Science
TL;DR: Crystal structures revealed the molecular basis of selectivity, and in vivo studies showed that an inhibitor protected mice from irinotecan-induced toxicity, and drugs may be designed to inhibit undesirable enzyme activities in essential microbial symbiotes to enhance chemotherapeutic efficacy.
Abstract: The dose-limiting side effect of the common colon cancer chemotherapeutic CPT-11 is severe diarrhea caused by symbiotic bacterial β-glucuronidases that reactivate the drug in the gut. We sought to target these enzymes without killing the commensal bacteria essential for human health. Potent bacterial β-glucuronidase inhibitors were identified by high-throughput screening and shown to have no effect on the orthologous mammalian enzyme. Crystal structures established that selectivity was based on a loop unique to bacterial β-glucuronidases. Inhibitors were highly effective against the enzyme target in living aerobic and anaerobic bacteria, but did not kill the bacteria or harm mammalian cells. Finally, oral administration of an inhibitor protected mice from CPT-11-induced toxicity. Thus, drugs may be designed to inhibit undesirable enzyme activities in essential microbial symbiotes to enhance chemotherapeutic efficacy.

762 citations

Journal ArticleDOI
21 Aug 2014-Immunity
TL;DR: It is shown that microbial-specific indoles regulated intestinal barrier function through the xenobiotic sensor, pregnane X receptor (PXR), and a direct chemical communication between the intestinal symbionts and PXR regulates mucosal integrity through a pathway that involves luminal sensing and signaling by TLR4.

644 citations

Journal ArticleDOI
11 Jan 2007-Oncogene
TL;DR: It is found that xenobiotic-mediated induction of CYP3A4 and MDR-1 gene transcription was inhibited by ketoconazole, a commonly used antifungal drug, and it is demonstrated for the first time that ketconazole represses the coordinated activation of genes involved in drug metabolism, by blocking activation of a specific subset of NRs.
Abstract: Individual variation in drug metabolism is a major cause of unpredictable side effects during therapy. Drug metabolism is controlled by a class of orphan nuclear receptors (NRs), which regulate expression of genes such as CYP (cytochrome)3A4 and MDR-1 (multi-drug resistance-1), that are involved in this process. We have found that xenobiotic-mediated induction of CYP3A4 and MDR-1 gene transcription was inhibited by ketoconazole, a commonly used antifungal drug. Ketoconazole mediated its effect by inhibiting the activation of NRs, human pregnenolone X receptor and constitutive androstene receptor, involved in regulation of CYP3A4 and MDR-1. The effect of ketoconazole was specific to the group of NRs that control xenobiotic metabolism. Ketoconazole disrupted the interaction of the xenobiotic receptor PXR with the co-activator steroid receptor co-activator-1. Ketoconazole treatment resulted in delayed metabolism of tribromoethanol anesthetic in mice, which was correlated to the inhibition of PXR activation and downmodulation of cyp3a11 and mdr-1 genes and proteins. These studies demonstrate for the first time that ketoconazole represses the coordinated activation of genes involved in drug metabolism, by blocking activation of a specific subset of NRs. Our results suggest that ketoconazole can be used as a pan-antagonist of NRs involved in xenobiotic metabolism in vivo, which may lead to novel strategies that improve drug effect and tolerance.

198 citations

Journal ArticleDOI
TL;DR: The crystal structures of representative β-glucuronidases from the Firmicutes Streptococcus agalactiae and Clostridium perfringens and the Proteobacterium Escherichia coli are reported and it is established that β- glucuronidsase inhibition does not alter the serum pharmacokinetics of irinotecan or its metabolites in mice.

186 citations


Cited by
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01 Jun 2012
TL;DR: SPAdes as mentioned in this paper is a new assembler for both single-cell and standard (multicell) assembly, and demonstrate that it improves on the recently released E+V-SC assembler and on popular assemblers Velvet and SoapDeNovo (for multicell data).
Abstract: The lion's share of bacteria in various environments cannot be cloned in the laboratory and thus cannot be sequenced using existing technologies. A major goal of single-cell genomics is to complement gene-centric metagenomic data with whole-genome assemblies of uncultivated organisms. Assembly of single-cell data is challenging because of highly non-uniform read coverage as well as elevated levels of sequencing errors and chimeric reads. We describe SPAdes, a new assembler for both single-cell and standard (multicell) assembly, and demonstrate that it improves on the recently released E+V-SC assembler (specialized for single-cell data) and on popular assemblers Velvet and SoapDeNovo (for multicell data). SPAdes generates single-cell assemblies, providing information about genomes of uncultivatable bacteria that vastly exceeds what may be obtained via traditional metagenomics studies. SPAdes is available online ( http://bioinf.spbau.ru/spades ). It is distributed as open source software.

10,124 citations

Journal ArticleDOI
25 Jul 2013-Immunity
TL;DR: Emerging clinical data suggest that cancer immunotherapy is likely to become a key part of the clinical management of cancer and may be more effective in combination with agents that target other steps of the cycle.

4,351 citations

Journal ArticleDOI
05 Jan 2018-Science
TL;DR: It is found that primary resistance to ICIs can be attributed to abnormal gut microbiome composition, and Antibiotics inhibited the clinical benefit of ICIs in patients with advanced cancer.
Abstract: Immune checkpoint inhibitors (ICIs) targeting the PD-1/PD-L1 axis induce sustained clinical responses in a sizable minority of cancer patients. We found that primary resistance to ICIs can be attributed to abnormal gut microbiome composition. Antibiotics inhibited the clinical benefit of ICIs in patients with advanced cancer. Fecal microbiota transplantation (FMT) from cancer patients who responded to ICIs into germ-free or antibiotic-treated mice ameliorated the antitumor effects of PD-1 blockade, whereas FMT from nonresponding patients failed to do so. Metagenomics of patient stool samples at diagnosis revealed correlations between clinical responses to ICIs and the relative abundance of Akkermansia muciniphila Oral supplementation with A. muciniphila after FMT with nonresponder feces restored the efficacy of PD-1 blockade in an interleukin-12-dependent manner by increasing the recruitment of CCR9+CXCR3+CD4+ T lymphocytes into mouse tumor beds.

3,258 citations

Journal ArticleDOI
Daniel S. Chen1, Ira Mellman1
19 Jan 2017-Nature
TL;DR: Clinical studies are beginning to define these factors as immune profiles that can predict responses to immunotherapy, suggesting that a broader view of cancer immunity is required.
Abstract: Immunotherapy is proving to be an effective therapeutic approach in a variety of cancers. But despite the clinical success of antibodies against the immune regulators CTLA4 and PD-L1/PD-1, only a subset of people exhibit durable responses, suggesting that a broader view of cancer immunity is required. Immunity is influenced by a complex set of tumour, host and environmental factors that govern the strength and timing of the anticancer response. Clinical studies are beginning to define these factors as immune profiles that can predict responses to immunotherapy. In the context of the cancer-immunity cycle, such factors combine to represent the inherent immunological status - or 'cancer-immune set point' - of an individual.

3,145 citations

Journal ArticleDOI
09 Feb 2017-Cell
TL;DR: As the molecular mechanisms of resistance to immunotherapy are elucidated, actionable strategies to prevent or treat them may be derived to improve clinical outcomes for patients.

3,131 citations