MicroRNAs (miRNAs) are fundamental post-transcriptional modulators of several critical cellular processes, a number of which are involved in host defense mechanisms. In particular, miRNA let-7 functions as an essential regulator of the function and differentiation of both innate and adaptive immune cells. Let-7 is involved in several human diseases, including cancer and viral infections. Several viral infections have found ways to dysregulate the expression of miRNAs. Extracellular vesicles (EV) are membrane-bound lipid structures released from many types of human cells that can transport proteins, lipids, mRNAs, and miRNAs, including let-7. After their release, EVs are taken up by the recipient cells and their contents released into the cytoplasm. Let-7-loaded EVs have been suggested to affect cellular pathways and biological targets in the recipient cells, and can modulate viral replication, the host antiviral response, and the action of cancer-related viruses. In the present review, we summarize the available knowledge concerning the expression of let-7 family members, functions, target genes, and mechanistic involvement in viral pathogenesis and host defense. This may provide insight into the development of new therapeutic strategies to manage viral infections.

Inflammatory bowel disease (IBD) is considered a chronic inflammatory and multifactorial disease of the gastrointestinal tract. Crohn’s disease (CD) and ulcerative colitis (UC) are two types of chronic IBD. Although there is no accurate information about IBD pathophysiology, evidence suggests that various factors, including the gut microbiome, environment, genetics, lifestyle, and a dysregulated immune system, may increase susceptibility to IBD. Moreover, inflammatory mediators such as interleukin‐6 (IL‐6) are involved in the immunopathogenesis of IBDs. IL‐6 contributes to T helper 17 (Th17) differentiation, mediating further destructive inflammatory responses in CD and UC. Moreover, Th1‐mediated responses participate in IBD, and the antiapoptotic IL‐6/IL‐6 receptor (IL‐6R)/signal transducer and activator of transcription 3 (STAT3) signals are responsible for preserving Th1 cells in the site of inflammation. It has been revealed that fecal bacteria isolated from UC‐active and UC‐remission patients stimulate the hyperproduction of several cytokines, such as IL‐6, tumor necrosis factor‐α (TNF‐α), IL‐10, and IL‐12. Given the importance of the IL‐6/IL‐6R axis, various therapeutic options exist for controlling or treating IBD. Therefore, alternative therapeutic approaches such as modulating the gut microbiome could be beneficial due to the failure of the target therapies so far. This review article summarizes IBD immunopathogenesis focusing on the IL‐6/IL‐6R axis and discusses available therapeutic approaches based on the gut microbiome alteration and IL‐6/IL‐6R axis targeting and treatment failure.

Many cellular signaling pathways contribute to the regulation of cell proliferation, division, motility, and apoptosis. Deregulation of these pathways contributes to tumor cell initiation and tumor progression. Lately, significant attention has been focused on the use of natural products as a promising strategy in cancer treatment. Quercetin is a natural flavonol compound widely present in commonly consumed foods. Quercetin has shown significant inhibitory effects on tumor progression via various mechanisms of action. These include stimulating cell cycle arrest or/and apoptosis as well as its antioxidant properties. Herein, we summarize the therapeutic effects of quercetin in gastrointestinal cancers (pancreatic, gastric, colorectal, esophageal, hepatocellular, and oral).

Abstract:: The precise and exquisite architecture of the retina is directly related to vision. Therefore, any mechanisms which are associated with disruption of retinal structure could affect on quality of vision. A large number studies indicated that several cellular and molecular processes involved in retina pathogenesis. Among different risk factors which are reported as important players in the retina diseases, deregulation of epigenetic contributors, have critical roles in the pathogenesis of these diseases. MicroRNAs (miRNAs) are a type of small non-coding RNAs that involved in various signaling pathways involved in the retina diseases. These molecules exert their function though targeting a sequence of cellular and molecular signals. Long-non coding RNAs (lncRNAs) and circular RNAs are other non-coding RNAs which can exert their regulatory roles via miRNA sponging. In this regard, it has been showed that miRNA sponging could modulate a variety of pathways in retinal diseases. Besides miRNAs, exosomes are other players in the pathogenesis of retinal diseases. Exosomes are biological vectors which could carry their cargos to recipient cells. The cargos of exosomes (i.e., proteins, lncRNAs, miRNAs, and fragments of DNA) enable to change behaviors of host cells. Here, we summarized the roles of miRNAs, miRNAs sponging and exosomes in the pathogenesis of retinal diseases.

No abstract