Downregulation of Acat1 by miR-21 may participate in liver fibrosis upon chronic DDT exposure

A comprehensive review of miR-21 in liver disease: Big impact of little things

microRNAs (miRNAs), a class of non-coding RNA with 20-24 nucleotides, are defined as the powerful regulators for gene expression. miR-21 is a multifunctional miRNA enriched in the circulatory system and multiple organs, which not only serves as a non-invasive biomarker in disease diagnosis, but also participates in many cellular activities. In various chronic liver diseases, the increase of miR-21 affects glycolipid metabolism, viral infection, inflammatory and immune cell activation, hepatic stellate cells activation and tissue fibrosis, and autophagy. Moreover, miR-21 is also a liaison in the deterioration of chronic liver disease to hepatocellular carcinoma (HCC), and it impacts on cell proliferation, apoptosis, migration, invasion, angiogenesis, immune escape, and epithelial-mesenchymal transformation by regulating target genes expression in different signaling pathways. In current research on miRNA therapy, some natural products can exert the hepatoprotective effects depending on the inhibition of miR-21 expression. In addition, miR-21-based therapeutic also play a role in regulating intracellular miR-21 levels and enhancing the efficacy of chemotherapy drugs. Herein, we systemically summarized the recent progress of miR-21 on biosynthesis, biomarker function, molecular mechanism and miRNA therapy in chronic liver disease and HCC, and looked forward to outputting some information to enable it from bench to bedside.

Per- and polyfluoroalkyl substances, polychlorinated biphenyls, organochlorine pesticides, and polybrominated diphenyl ethers and dysregulation of MicroRNA expression in humans and animals-A systematic review

BACKGROUND

Persistent organic pollutants (POPs) are chemicals characterized by their environmental persistence. Evidence suggests that exposure to POPs, which is ubiquitous, is associated with microRNA (miRNA) dysregulation. miRNA are key regulators in many physiological processes. It is thus of public health concern to understand the relationships between POPs and miRNA as related to health outcomes.

OBJECTIVES

This systematic review evaluated the relationship between widely recognized, intentionally manufactured, POPs, including per- and polyfluoroalkyl substances (PFAS), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (dichlorodiphenyltrichloroethane [DDT], dichlorodiphenyldichloroethylene [DDE], hexachlorobenzene [HCB]), with miRNA expression in both human and animal studies.

METHODS

We used PubMed and Embase to systematically search the literature up to September 29th, 2023. Search results for human and animal studies were included if they incorporated at least one POP of interest in relation to at least one miRNA. Data were synthesized to determine the direction and significance of associations between POPs and miRNA. We utilized ingenuity pathway analysis to review disease pathways for miRNA that were associated with POPs.

RESULTS

Our search identified 38 eligible studies: 9 in humans and 29 in model organisms. PFAS were associated with decreased expression of miR-19, miR-193b, and miR-92b, as well as increased expression of miR-128, miR-199a-3p, and miR-26b across species. PCBs were associated with increased expression of miR-15a, miR-1537, miR-21, miR-22-3p, miR-223, miR-30b, and miR-34a, as well as decreased expression of miR-130a and let-7b in both humans and animals. Pathway analysis for POP-associated miRNA identified pathways related to carcinogenesis.

DISCUSSION

This is the first systematic review of the association of POPs with miRNA in humans and model organisms. Large-scale prospective human studies are warranted to examine the role of miRNA as mediators between POPs and health outcomes.

Quercetin protects human liver cells from o,p'-DDT-induced toxicity by suppressing Nrf2 and NADPH oxidase-regulated ROS production

Epidemiologic studies have revealed that Dichlorodiphenyltrichloroethane (DDT) and its metabolites are associated with liver diseases. However, there has been little emphasis on the mechanism underlying liver toxicity of o,p'-DDT and relevant effective inhibitors investigation. This study indicated o,p'-DDT exposure significantly decreased cell viability and promoted lactate dehydrogenase (LDH) release based on the investigation of cytotoxicity by trypan blue exclusion counts, MTT, and lactate dehydrogenase (LDH) assays. Comet, micronuclei, and DNA-protein crosslinks (DPC) assays demonstrated o,p'-DDT exposure increased the comet parameters, micronuclei frequency, and DPC coefficient. Meanwhile, we found o,p'-DDT induced mitochondria-dependent apoptosis, which is characterized by the loss of of mitochondrial membrane potential (Δψm), decreased Bcl-2 expression, and increased protein levels of Bax, cytochrome c, activated-caspase-9, and activated-caspase-3. Furthermore, o,p'-DDT induced reactive oxygen species (ROS) overproduction, decreased the protein levels of nuclear factor erythroid-derived 2-like 2 (Nrf2) in the nuclear, and enhanced the expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. However, quercetin treatment significantly antagonized o,p'-DDT-induced cytotoxicity, genotoxicity, and apoptosis as well as effects on ROS, Nrf2, and NADPH oxidase. Taken together, these findings suggested quercetin could alleviate o,p'-DDT-induced toxicity in HL-7702 cells via inhibiting ROS production, which is modulated by down-regulating nuclear Nrf2 levels and NADPH oxidase expression.

MicroRNAs in organ fibrosis: From molecular mechanisms to potential therapeutic targets

Fibrosis is caused by chronic tissue injury and characterized by the excessive deposition of extracellular matrix (ECM) that ultimately results in organ failure and death. Owing to lacking of effective treatment against tissue fibrosis, it causes a high morbidity and mortality worldwide. Thus, it is of great importance to find an effective therapy strategy for the treatment of fibrosis. MicroRNAs (miRNAs) play vital roles in many biological processes by targeting downstream genes. Numerous studies demonstrated that miRNAs served as biomarkers of various diseases, suggesting the potential therapeutic targets for diseases. It was recently reported that miRNAs played an important role in the development of organ fibrosis, which showed a promising prospect against fibrosis by targeting intervention. Here, we summarize the roles of miRNAs in the process of organ fibrosis, including liver, lung, heart and kidney, and highlight miRNAs being novel therapeutic targets for organ fibrosis.