Interleukin 21 Drives a Hypermetabolic State and CD4+ T-Cell-Associated Pathogenicity in Chronic Intestinal Inflammation.

BACKGROUND & AIMS: Incapacitated regulatory T cells (Tregs) contribute to immune-mediated diseases. Inflammatory Tregs are evident during human inflammatory bowel disease; however, mechanisms driving the development of these cells and their function are not well understood. Therefore, we investigated the role of cellular metabolism in Tregs relevant to gut homeostasis. METHODS: Using human Tregs, we performed mitochondrial ultrastructural studies via electron microscopy and confocal imaging, biochemical and protein analyses using proximity ligation assay, immunoblotting, mass cytometry and fluorescence-activated cell sorting, metabolomics, gene expression analysis, and real-time metabolic profiling utilizing the Seahorse XF analyzer. We used a Crohn's disease single-cell RNA sequencing dataset to infer the therapeutic relevance of targeting metabolic pathways in inflammatory Tregs. We examined the superior functionality of genetically modified Tregs in CD4+ T-cell-induced murine colitis models. RESULTS: Mitochondria-endoplasmic reticulum appositions, known to mediate pyruvate entry into mitochondria via voltage-dependent anion channel 1 (VDAC1), are abundant in Tregs. VDAC1 inhibition perturbed pyruvate metabolism, eliciting sensitization to other inflammatory signals reversible by membrane-permeable methyl pyruvate supplementation. Notably, interleukin (IL) 21 diminished mitochondria-endoplasmic reticulum appositions, resulting in enhanced enzymatic function of glycogen synthase kinase 3 ß, a putative negative regulator of VDAC1, and a hypermetabolic state that amplified Treg inflammatory response. Methyl pyruvate and glycogen synthase kinase 3 ß pharmacologic inhibitor (LY2090314) reversed IL21-induced metabolic rewiring and inflammatory state. Moreover, IL21-induced metabolic genes in Tregs in vitro were enriched in human Crohn's disease intestinal Tregs. Adoptively transferred Il21r-/- Tregs efficiently rescued murine colitis in contrast to wild-type Tregs. CONCLUSIONS: IL21 triggers metabolic dysfunction associated with Treg inflammatory response. Inhibiting IL21-induced metabolism in Tregs may mitigate CD4+ T-cell-driven chronic intestinal inflammation.

Interleukin-21 Drives a Hypermetabolic State and CD4+ T Cell-associated Pathogenicity in Chronic Intestinal Inflammation.

BACKGROUND & AIMS: Incapacitated regulatory T cells (Tregs) contribute to immune-mediated diseases. Inflammatory Tregs are evident during human inflammatory bowel disease (IBD); however, mechanisms driving the development of these cells and their function are not well understood. Therefore, we investigated the role of cellular metabolism in Tregs relevant to gut homeostasis. METHODS: Using human Tregs, we performed mitochondrial ultrastructural studies via electron microscopy and confocal imaging, biochemical and protein analyses using proximity ligation assay, immunoblotting, mass cytometry and fluorescence-activated cell sorting, metabolomics, gene expression analysis, and real-time metabolic profiling utilizing Seahorse XF analyzer. We utilized Crohn's disease single-cell RNA sequencing dataset to infer therapeutic relevance of targeting metabolic pathways in inflammatory Tregs. We examined the superior functionality of genetically-modified Tregs in CD4+ T cell-induced murine colitis models. RESULTS: Mitochondria-endoplasmic reticulum (ER) appositions, known to mediate pyruvate entry into mitochondria via VDAC1, are abundant in Tregs. VDAC1 inhibition perturbed pyruvate metabolism, eliciting sensitization to other inflammatory signals reversible by membrane-permeable methyl pyruvate (MePyr) supplementation. Notably, IL-21 diminished mitochondria-ER appositions, resulting in enhanced enzymatic function of glycogen synthase kinase 3 ß (GSK3ß), a putative negative regulator of VDAC1, and a hypermetabolic state that amplified Treg inflammatory response. MePyr and GSK3ß pharmacologic inhibitor (LY2090314) reversed IL-21-induced metabolic rewiring and inflammatory state. Moreover, IL-21-induced metabolic genes in Tregs in vitro were enriched in human Crohn's disease intestinal Tregs. Adoptively transferred Il21r-/- Tregs efficiently rescued murine colitis in contrast to wild-type Tregs. CONCLUSIONS: IL-21 triggers metabolic dysfunction associated with Treg inflammatory response. Inhibiting IL-21-induced metabolism in Tregs may mitigate CD4+ T cell-driven chronic intestinal inflammation.

Role of circulating microRNAs in non-small cell lung carcinoma.

INTRODUCTION: Non-small cell lung cancer (NSCLC) is the leading cause of mortality globally. Early imaging detection modalities are associated with high false-positive rates and radiation exposure. A non-invasive biomarker can serve as an improvised method for early detection. MicroRNAs can serve as a potential non-invasive biomarker as they are stable in circulation, tissue or biological process-specific, easy to detect, cost-effective, and not associated with radiation hazards. This study validates circulating microRNA in NSCLC of the Indian population and studies its correlation with clinicopathological parameters. MATERIALS AND METHODS: Circulating microRNA (-miR-193b, miR-301a, miR-7, and miR-25) was evaluated in 101 cases of tissue-proven NSCLC and 28 controls in serum samples. RESULTS: There were 67 male and 34 female patients (Male: Female = 1.97:1). The age range was 25 to 86 years with a median age of 60 years. There was a significant upregulation in the expression of miR-193b in the NSCLC group as compared to controls (P = 0.034). MiR-7 was also upregulated while miR-25 and miR-301a were downregulated in NSCLC as compared to controls; however, a level of significance was not achieved. ROC curve analysis for miR-193b showed an AUC of 0.636 (95% CI, 0.522-0.750; P-value = 0.036) between NSCLC cases and controls. CONCLUSION: The present study showed variable expression of the above-studied miRNAs. MiR-193b showed a significant upregulation in cancer patients; however, the other three miRNAs were not conclusive. This suggests that profiling of microRNA in each population is essential to search for a valid non-invasive biomarker in that population.

Identification of PI3K-AKT signaling as the dominant altered pathway in intestinal type ampullary cancers through whole-exome sequencing.

BACKGROUND: The genetic landscape of intestinal (INT) and pancreatobiliary (PB) type ampullary cancer (AC) has been evolving with distinct as well as overlapping molecular profiles. METHODS: We performed whole-exome sequencing in 37 cases of AC to identify the targetable molecular profiles of INT and PB tumors. Paired tumor-normal sequencing was performed on the HiSeq 2500 Illumina platform. RESULTS: There were 22 INT, 13 PB, and two cases of mixed differentiation of AC that exhibited a total of 1,263 somatic variants in 112 genes (2-257 variants/case) with 183 somatic deleterious variants. INT showed variations in 78 genes (1-31/case), while PB showed variations in 51 genes (1-29/case). Targetable mutations involving one or more major pathways were found in 86.5% of all ACs. Mutations in APC, CTNNB1, SMAD4, KMT2, EPHA, ERBB, and Notch genes were more frequent in INT tumors, while chromatin remodeling complex mutations were frequent in PB tumors. In the major signaling pathways, the phosphoinositide 3-kinase (PI3)/AKT and RAS/mitogen-activated protein kinase (MAPK) pathways were significantly mutated in 70% of cases (82% INT, 46% PB, p = .023), with PI3/AKT mutation being more frequent in INT and RAS/MAPK in PB tumors. Tumor mutation burden was low in both differentiation types, with 1.6/Mb in INT and 0.8/Mb in PB types (p =.217). CONCLUSIONS: The exome data suggest that INT types are genetically more unstable than PB and involve mutations in tumor suppressors, oncogenes, transcription factors, and chromatin remodeling genes. The spectra of the genetic profiles of INT and PB types suggested primary targeting of PI3/AKT in INT and RAS/RAF and PI3/AKT pathways in PB carcinomas.

Prevalence and spectrum of pathogenic germline variants in intestinal and pancreatobiliary type of ampullary cancer.

BACKGROUND: Ampullary cancer may occur as a component of hereditary cancer syndromes. Mutations in inherited cancer susceptibility genes play a therapeutic role and its knowledge in ampullary cancer is lacking. METHODS: Thirty-seven cases of ampullary carcinoma were subjected to tumor-normal whole exome sequencing with mean coverage of 100X (blood) and 200X (tumor). Data were analyzed and correlated with intestinal and pancreatobiliary differentiation. RESULTS: There were 22 intestinal, 13 pancreatobiliary and 2 cases of mixed differentiation. One hundred and forty-three germline variations with at least >1 pathogenic germline variants (PGVs) across 83 genes were found in 36 of 37 patients. Twelve genes (14.5 %) showed >3, 20 genes (24.1 %) showed two and 51 genes (61.4 %) showed one PGVs. Intestinal differentiation showed higher PGVs (117 variants, 73 genes) than pancreatobiliary differentiation (85 variants, 62 genes). PGVs in ERCC5, MEN1, MSH3, CHEK1, TP53, APC, FANCA, ERBB2, BRCA1, BRCA2, RTEL1, HNF1A and PTCH1 were seen in >50 % of cases. Nine genes harbored somatic second hits in 14 cases. PGVs in DNA damage-repair, homologous recombination repair, TP53 transcriptional regulation, DNA double stranded breaks, cell cycle and nucleotide excision repair genes were seen in all cases of intestinal and pancreatobiliary differentiation, while DNA mismatch repair genes were found in 81.8 % of intestinal and 84.6 % of pancreatobiliary cancers. Functional pathway analysis showed that DNA damage-repair, double stranded break repair, mismatch repair, homologous recombination repair and TP53 transcriptional regulation genes were altered in both while nucleotide-excision repair was significantly mutated in intestinal type and cell-cycle genes in pancreatobiliary type (p < 0.05). CONCLUSION: This study reports spectrum of PGVs in intestinal and pancreatobiliary differentiation of ampullary carcinoma at higher frequency through whole exome sequencing. PGVs were most frequently found in DNA repair genes. Detecting PGVs through tumor-normal sequencing may identify therapeutically actionable and double-hit mutations that can guide towards appropriate management.

NMR-Based Serum Metabolomics of Patients with Takayasu Arteritis: Relationship with Disease Activity.

Takayasu arteritis (TA) is a large vessel vasculitis of unknown pathogenesis. Assessment of disease activity is a challenge, and there is an unmet need for relevant biomarker(s). In our previous study, NMR based serum metabolomics had revealed distinctive metabolic signatures in TA patients compared with age/sex matched healthy controls and systemic lupus erythematosus (SLE). In this study we investigate whether the metabolites correlate with disease activity. Patients with TA fulfilling American College of Rheumatology (ACR) criteria were enrolled, and disease activity was assessed using Indian Takayasu Clinical Activity Score using acute phase reactant-erythrocyte sedimentation rate [ITAS-A (ESR)]. Sera were analyzed using 800 MHz NMR spectrometer to identify metabolites [based on partial least squares discriminant analysis (PLS-DA) VIP (variable importance in projection) score > 1.0 and permutation test, p-value <0.01]. 45 active and 53 inactive TA patients with median age 27 [(IQR) 22-35 years] and 27 [(IQR) 23-37 years], female to male ratio 3.5:1 and 4.9:1, and median duration of illness 5 [(IQR) 2-9 years] and 3 [(IQR) 1-6 years], respectively, were enrolled. The key metabolites with highest discriminatory potential in active TA (ITAS-A ≥ 4) were glutamate and N-acetyl glycoprotein (NAG), both elevated, with area under the curve 0.775 and 0.769 ( p-value <0.001). On follow up assessment, metabolic spectra started to differ with change in disease activity. This large cohort of patients revealed metabolic profiles discriminating between clinically active and inactive TA patients. It suggests glutamate and NAG have strong potential as biomarkers for disease activity in TA and may serve as a guide to therapy. We are now working to further validate these results in longitudinal studies.