Project description:Seven carbon autotrophic fixation pathways were described so far. However, it is not common to find the co-existence of more than one cycle in a single cell. Here, we describe a thermophilic bacterium Carbonactinospora thermoautotrophica StC with a unique and versatile carbon metabolism. StC was isolated from a consortium found in a burning organic pile that exhibits an optimal growth temperature between 55° and 65° C. The genome analyses suggested that the strain StC potentially performs two-carbon fixation pathways, Calvin-Benson-Bassham (CBB) cycle and the Reductive citrate cycle (rTCA) and preserve a microcompartment related with CO2 concentration. To better understand the carbon fixation in StC strain, the expression of the genes of bacterial cells grown autotrophically and heterotrophically were analyzed. For our surprise the data showed the co-existing of the both carbon fixation pathways - CBB and rTCA cycles - in a cultivable thermophilic chemoautotrophic bacterium Carbonactinospora thermoautotrophica strain StC, based on integrated omics of genomics, transcriptomics, and proteomics. These two cycles working together may help microorganisms to improve the CO2 fixation. The knowledge about the co-occurrence of carbon cycle in a single cell leads open a question ‘why microorganisms use multiple pathways to fix carbon and what the advantage for this strategy?’. Advancing on this is a key to better understand the biological carbon fixation mechanism in thermophiles and prospecting the repurposing of enzymes in synthetic biology for biotechnological applications.
Project description:Co-existence of CBB cycle and rTCA carbon fixation pathway in thermophilic Actinomycetota Carbonactinospora thermoautotrophica StC and correlation with the CO2-concentrating microcompartment
Project description:To investigate the pathogenesis of slow transit constipation (STC), we have employed microarray-based miRNA analysis as a discovery platform to identify miRNAs potentially related with STC pathogenesis.Full-thickness specimens were obtained from colons of STC patients undergoing total colectomy and ileorectal anastomosis or subtotal colectomy with antiperistaltic cecoproctostomy. And patients undergoing radical surgery for non-obstructing colon cancer (left colon cancer) as control. These patients were not constipated and had no colonic dilatation. The control specimens were obtained at least 5 cm from the resection margin in tumor free areas. Expression of five miRNAs (miRNA-128, miRNA-129-3p, miRNA-20b,miRNA-27b and miRNA-30b) from this signature was identified by arbitrarily setting the threshold at a fold change of 1.3 or above combined with p < 0.05 in the same RNA samples. Expression of miRNAs in the colon may be involved in STC pathogenesis. The samples were obtained and washed with cold PBS, transported in liquid nitrogen and immediately stored in liquid nitrogen after removal. Total RNA was isolated from frozen histologic specimens using a mirVana™ RNA isolation Kit.
Project description:To investigate the pathogenesis of slow transit constipation (STC), we have employed microarray-based miRNA analysis as a discovery platform to identify miRNAs potentially related with STC pathogenesis.Full-thickness specimens were obtained from colons of STC patients undergoing total colectomy and ileorectal anastomosis or subtotal colectomy with antiperistaltic cecoproctostomy. And patients undergoing radical surgery for non-obstructing colon cancer (left colon cancer) as control. These patients were not constipated and had no colonic dilatation. The control specimens were obtained at least 5 cm from the resection margin in tumor free areas. Expression of five miRNAs (miRNA-128, miRNA-129-3p, miRNA-20b,miRNA-27b and miRNA-30b) from this signature was identified by arbitrarily setting the threshold at a fold change of 1.3 or above combined with p < 0.05 in the same RNA samples. Expression of miRNAs in the colon may be involved in STC pathogenesis.
Project description:The RNA methyltransferase METTL3 is responsible for the generation of m6A, the most abundant modification mark on mRNA and long non-coding RNA. Accumulating evidence suggests numerous roles of METTL3 in cancer initiation and progression and highlights the potential for targeting this enzyme in oncology. STC-15 is a potent and selective METTL3 inhibitor and the first RNA modifying enzyme inhibitor to enter human clinical development. It is structurally related to the previously published tool inhibitors STM2457 and STM3675. We previously identified the induction of a cancer cell-intrinsic interferon response following pharmacological inhibition of METTL3, leading to activation of T-cell-mediated anti-tumour response. Here, we profiled m6A levels at nucleotide resolution using GLORI and characterised RNA changes following METTL3 inhibition with STC-15 or STM3675. Following loss of m6A, we uncovered aberrant mRNA transcripts arising from intron retention (IR) and transcriptional run-on (RO) events downstream of m6A-enriched exons in human cancer cells and in tumour samples in vivo. We found that these IR and RO events produce double-stranded RNA and are bound by the cytoplasmic dsRNA sensor MDA5.Using preclinical in vitro and in vivo models, we characterised in detail the anti-tumour immune responses induced by STC-15. Our study reveals how METTL3 inhibition leads to dsRNA accumulation, which triggers a type I interferon response and induces anti-tumour immunity. Together, these findings provide a mechanistic rationale for STC-15 as a novel anti-cancer drug both as monotherapy and in combination with anti-PD1 checkpoint inhibitors.
Project description:The RNA methyltransferase METTL3 is responsible for the generation of m6A, the most abundant modification mark on mRNA and long non-coding RNA. Accumulating evidence suggests numerous roles of METTL3 in cancer initiation and progression and highlights the potential for targeting this enzyme in oncology. STC-15 is a potent and selective METTL3 inhibitor and the first RNA modifying enzyme inhibitor to enter human clinical development. It is structurally related to the previously published tool inhibitors STM2457 and STM3675. We previously identified the induction of a cancer cell-intrinsic interferon response following pharmacological inhibition of METTL3, leading to activation of T-cell-mediated anti-tumour response. Here, we profiled m6A levels at nucleotide resolution using GLORI and characterised RNA changes following METTL3 inhibition with STC-15 or STM3675. Following loss of m6A, we uncovered aberrant mRNA transcripts arising from intron retention (IR) and transcriptional run-on (RO) events downstream of m6A-enriched exons in human cancer cells and in tumour samples in vivo. We found that these IR and RO events produce double-stranded RNA and are bound by the cytoplasmic dsRNA sensor MDA5.Using preclinical in vitro and in vivo models, we characterised in detail the anti-tumour immune responses induced by STC-15. Our study reveals how METTL3 inhibition leads to dsRNA accumulation, which triggers a type I interferon response and induces anti-tumour immunity. Together, these findings provide a mechanistic rationale for STC-15 as a novel anti-cancer drug both as monotherapy and in combination with anti-PD1 checkpoint inhibitors.