microRNA Pathway Research Articles

Abstract B004: Dealing with prostate cancer racial disparity: Galeterone and next-generation galeterone analog VNPP433-3β potently inhibits proliferation of prostate cancer cells from African American patient by degrading AR and Mnk1/2

Abstract Prostate cancer incidence and mortality rates are remarkably higher in African-American (AA) men as compared to their European-American (EA) counterparts even after factoring in socio economic status. The disproportionate incidence of prostate cancer and associated mortality in African men is currently becoming more evident as Several studies have reported significant variations in genetic, molecular, epigenetic, microRNA, and cell signaling pathways in patients of Caucasian and African race. As androgen is implicated in prostate cancer progression and about 90% of the cases are Androgen-dependent, blocking androgen action is an effective strategy in treating prostate cancer. Previously, we reported that galeterone and VNPP433-3β, a next generation galeterone analog potently inhibit metastatic castration resistant prostate cancer of Caucasian origin in vitro and in vivo by degrading AR/AR-V7 and Mnk1/2. Since the prostate cancer patients of African descent express significant levels of AR and Mnk1/2, we investigated the efficacy of galeterone and VNPP433-3β in treating prostate cancer of African men. Cell proliferation assay using the cell lines MDA-PCa 2b and RC77 T/E derived from AA prostate cancer patient demonstrates that galeterone and VNPP433-3β can effectively inhibit prostate cancer of African descent at very low concentration. These cell lines are Androgen-sensitive and further biochemical studies reveal that galeterone and VNPP433-3β degrade AR and Mnk1/2 in RC77 T/E and MDA-PCa 2b cell lines, thereby inhibiting its proliferation. Galeterone and VNPP433-3β significantly decrease the half-life of AR in these cell lines by increasing the rate of ubiquitination and proteasomal degradation of AR. Therefore, galeterone and VNPP433-3β hold significant promise for the clinical management of prostate cancer in patients of African descent Citation Format: Elizabeth Thomas, Retheesh Sulochana Thankan, Puranik Purushottachar, Vincent C.O. Njar. Dealing with prostate cancer racial disparity: Galeterone and next-generation galeterone analog VNPP433-3β potently inhibits proliferation of prostate cancer cells from African American patient by degrading AR and Mnk1/2 [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr B004.

MicroRNA-mediated translational pathways are regulated in the orbitofrontal cortex and peripheral blood samples during acute abstinence from heroin self-administration.

Opioid misuse in the United States contributes to >70% of annual overdose deaths. To develop additional therapeutics that may prevent opioid misuse, further studies on the neurobiological consequences of opioid exposure are needed. Here we sought to characterize molecular neuroadaptations involving microRNA (miRNA) pathways in the brain and blood of adult male rats that self-administered the opioid heroin. miRNAs are ∼18-24 nucleotide RNAs that regulate protein expression by preventing mRNA translation into proteins. Manipulation of miRNAs and their downstream pathways can critically regulate drug seeking behavior. We performed small-RNA sequencing of miRNAs and proteomics profiling on tissue from the orbitofrontal cortex (OFC), a brain region associated with heroin seeking, following 2days of forced abstinence from self-administration of 0.03mg/kg/infusion heroin or sucrose. Heroin self-administration resulted in a robust shift of the OFC miRNA profile, regulating 77 miRNAs, while sucrose self-administration only regulated 9 miRNAs that did not overlap with the heroin-induced profile. Conversely, proteomics revealed dual regulation of seven proteins by both heroin and sucrose in the OFC. Pathway analysis determined that heroin-associated miRNA pathways are predicted to target genes associated with the term "prion disease," a term that was also enriched in the heroin-induced protein expression dataset. Lastly, we confirmed that a subset of heroin-induced miRNA expression changes in the OFC are regulated in peripheral serum and correlate with heroin infusions. These findings demonstrate that peripheral blood samples may have biomarker utility for assessment of drug-induced miRNA pathway alterations that occur in the brain following chronic drug exposure.

MicroRNA biomarkers target genes and pathways associated with type 2 diabetes

Aims/Hypothesis:Our prior analysis of the Diabetes Prevention Program study identified a subset of five miRNAs that predict incident type 2 diabetes. The purpose of this study was to identify mRNAs and biological pathways targeted by these five miRNAs to elucidate potential mechanisms of risk and responses to the tested interventions. MethodsUsing experimentally validated data from miRTarBase version 8.0 and R (2021), we identified mRNAs with strong evidence to be regulated by individual or combinations of the five predictor miRNAs. Overrepresentation of the mRNA targets was assessed in pathways from the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation database. ResultsThe five miRNAs targeted 167 pathways and 122 mRNAs. Nine of the pathways have known associations with type 2 diabetes: Insulin signaling, Insulin resistance, Diabetic cardiomyopathy, Type 2 diabetes, AGE-RAGE signaling in diabetic complications, HIF-1 signaling, TGF-beta signaling, PI3K/Akt signaling, and Adipocytokine signaling pathways. Vascular endothelial growth factor A (VEGFA) has prior genetic associations with risk for type 2 diabetes and was the most commonly targeted mRNA for this set of miRNAs. Conclusions/Interpretation:These findings show that miRNA predictors of incident type 2 diabetes target mRNAs and pathways known to underlie risk for type 2 diabetes. Future studies should evaluate miRNAs as potential therapeutic targets for preventing and treating type 2 diabetes.

Adenovirus VA RNAs impair maturation of primary microRNA.

Adenovirus expresses two non-coding virus-associated (VA) RNAs: VA I RNA and VA II RNA. Adenovirus-expressed VA RNAs interfere with the microRNA (miRNA) pathway by competing with precursor miRNAs. The processing pattern of primary miRNA (pri-miRNA) and factors to affect its processing are not exactly known when using adenovirus for the delivery of pri-miRNA. To observe pri-miRNA processing, plasmid construct encoding pri-miRNA was co-transfected with VA I/II RNA expression plasmid, or recombinant adenovirus encoding pri-miRNA was generated and infected. Levels of miRNAs, VA I RNA and VA II RNA were analyzed by a quantitative real-time PCR (RT-PCR). VA I-II full-length RNA was analyzed by a RT-PCR. RNA immunoprecipitation analysis to pull-down the VA I-II full-length RNA binding with Drosha was conducted with Drosha antibody. pri-miRNA was normally processed into mature miRNA when it was expressed in cells using plasmid. However, miRNA maturation was impaired when pri-miRNA was delivered and expressed using adenovirus. Of note, pri-miRNA processing was observed to be blocked by VA RNA expression. Such blocked processing could be recovered by introducing antisense RNA of VA RNA, anti-3'VA RNA. In addition, VA RNAs were transcribed into VA I-II full-length RNA, which was found to bind and sequester Drosha. Adenovirus infection downregulated the processing of pri-miRNAs in cells, and such downregulation could be derived from VA I-II full-length RNAs in pri-miRNA-like form through competitively binding to Drosha protein. These results indicated that the expression of adenovirus VA RNAs should be inhibited for successful delivery and expression of pri-miRNA or shRNA in cells using adenovirus.

The microRNA pathway core genes are indispensable for development and reproduction in the brown planthopper, Nilaparvata lugens.

MicroRNAs (miRNAs) are small single-stranded non-coding RNAs involved in a variety of cellular events by regulating gene expression at the post-transcriptional level. Several core genes in miRNA biogenesis have been reported to participate in a wide range of physiological events, in some insect species. However, the functional significance of miRNA pathway core genes in Nilaparvata lugens remains unknown. In the present study, we conducted a systematic characterisation of five core genes involved in miRNA biogenesis. We first performed spatiotemporal expression analysis and found that miRNA core genes exhibited similar expression patterns, with high expression levels in eggs and relatively high transcriptional levels in the ovaries and fat bodies of females. RNA interference experiments showed that injecting third-instar nymphs with dsRNAs targeting the miRNA core genes, NlAgo1, NlDicer1, and NlDrosha resulted in high mortality rates and various degrees of body melanism, moulting defects, and wing deformities. Further investigations revealed that the suppression of miRNA core genes severely impaired ovarian development and oocyte maturation, resulting in significantly reduced fecundity and disruption of intercellular spaces between follicle cells. Moreover, the expression profiles of miR-34-5p, miR-275-3p, miR-317-3p, miR-14, Let-7-1, and miR-2a-3p were significantly altered in response to the knockdown of miRNA core genes mixture, suggesting that they play essential roles in regulating miRNA-mediated gene expression. Therefore, our results provide a solid theoretical basis for the miRNA pathway in N. lugens and suggest that the NlAgo1, NlDicer1, and NlDrosha-dependent miRNA core genes are essential for the development and reproduction of this agricultural pest.

Role of the proline-rich disordered domain of DROSHA in intronic microRNA processing.

DROSHA serves as a gatekeeper of the microRNA (miRNA) pathway by processing primary transcripts (pri-miRNAs). While the functions of structured domains of DROSHA have been well documented, the contribution of N-terminal proline-rich disordered domain (PRD) remains elusive. Here we show that the PRD promotes the processing of miRNA hairpins located within introns. We identified a DROSHA isoform (p140) lacking the PRD, which is produced by proteolytic cleavage. Small RNA sequencing revealed that p140 is significantly impaired in the maturation of intronic miRNAs. Consistently, our minigene constructs demonstrated that PRD enhances the processing of intronic hairpins, but not those in exons. Splice site mutations did not affect the PRD's enhancing effect on intronic constructs, suggesting that the PRD acts independently of splicing reaction by interacting with sequences residing within introns. The N-terminal regions from zebrafish and Xenopus DROSHA can replace the human counterpart, indicating functional conservation despite poor sequence alignment. Moreover, we found that rapidly evolving intronic miRNAs are generally more dependent on PRD than conserved ones, suggesting a role of PRD in miRNA evolution. Our study reveals a new layer of miRNA regulation mediated by a low-complexity disordered domain that senses the genomic contexts of miRNA loci.

Comparative efficacy and pharmacological mechanism of Chinese patent medicines against anthracycline-induced cardiotoxicity: An integrated study of network meta-analysis and network pharmacology approach.

This study aimed to evaluate the efficacy of Chinese patent medicines (CPMs) combined with dexrazoxane (DEX) against anthracycline-induced cardiotoxicity (AIC) and further explore their pharmacological mechanism by integrating the network meta-analysis (NMA) and network pharmacology approach. We searched for clinical trials on the efficacy of DEX + CPMs for AIC until March 10, 2023 (Database: PubMed, Embase, Cochrane Library, Chinese National Knowledge Infrastructure, China Science and Technology Journal and China Online Journals). The evaluating outcomes were cardiac troponin I (cTnI) level, creatine kinase MB (CK-MB) level, left ventricular ejection fraction (LVEF) value, and electrocardiogram (ECG) abnormal rate. Subsequently, the results of NMA were further analyzed in combination with network pharmacology. We included 14 randomized controlled trials (RCTs) and 1 retrospective cohort study (n = 1,214), containing six CPMs: Wenxinkeli (WXKL), Cinobufotalin injection (CI), Shenqifuzheng injection (SQFZ), Shenmai injection (SM), Astragalus injection (AI) and AI + CI. The NMA was implemented in Stata (16.0) using the mvmeta package. Compared with using DEX only, DEX + SM displayed the best effective for lowering cTnI level (MD = -0.44, 95%CI [-0.56, -0.33], SUCRA 93.4%) and improving LVEF value (MD = 14.64, 95%CI [9.36, 19.91], SUCRA 98.4%). DEX + SQFZ showed the most effectiveness for lowering CK-MB level (MD = -11.57, 95%CI [-15.79, -7.35], SUCRA 97.3%). And DEX + AI + CI has the highest effectiveness for alleviating ECG abnormalities (MD = -2.51, 95%CI [-4.06, -0.96], SUCRA 96.8%). So that we recommended SM + DEX, SQFZ + DEX, and DEX + AI + CI as the top three effective interventions against AIC. Then, we explored their pharmacological mechanism respectively. The CPMs' active components and AIC-related targets were screened to construct the component-target network. The potential pathways related to CPMs against AIC were determined by KEGG. For SM, we identified 118 co-targeted genes of active components and AIC, which were significantly enriched in pathways of cancer pathways, EGFR tyrosine kinase inhibitor resistance and AGE-RAGE signaling pathway in diabetic complications. For SQFZ, 41 co-targeted genes involving pathways of microRNAs in cancer, Rap1 signaling pathway, MAPK signaling pathway, and lipid and atherosclerosis. As for AI + CI, 224 co-targeted genes were obtained, and KEGG analysis showed that the calcium signaling pathway plays an important role except for the consistent pathways of SM and SQFZ in anti-AIC. DEX + CPMs might be positive efficacious interventions from which patients with AIC will derive benefits. DEX + SM, DEX + SQFZ, and DEX + AI + CI might be the preferred intervention for improving LVEF value, CK-MB level, and ECG abnormalities, respectively. And these CPMs play different advantages in alleviating AIC by targeting multiple biological processes.

Orbitofrontal cortex microRNAs support long-lasting heroin seeking behavior in male rats

Recovery from opioid use disorder (OUD) and maintenance of abstinence from opioid use is hampered by perseverant drug cravings that may persist for months after cessation of drug use. Drug cravings can intensify during the abstinence period, a phenomenon referred to as the ‘incubation of craving’ that has been well-described in preclinical studies. We previously reported that animals that self-administered heroin at a dosage of 0.075 mg/kg/infusion (HH) paired with discrete drug cues displayed robust incubation of heroin craving behavior after 21 days (D) of forced abstinence, an effect that was not observed with a lower dosage (0.03 mg/kg/infusion; HL). Here, we sought to elucidate molecular mechanisms underlying long-term heroin seeking behavior by profiling microRNA (miRNA) pathways in the orbitofrontal cortex (OFC), a brain region that modulates incubation of heroin seeking. miRNAs are small noncoding RNAs with long half-lives that have emerged as critical regulators of drug seeking behavior but their expression in the OFC has not been examined in any drug exposure paradigm. We employed next generation sequencing to detect OFC miRNAs differentially expressed after 21D of forced abstinence between HH and HL animals, and proteomics analysis to elucidate miRNA-dependent translational neuroadaptations. We identified 55 OFC miRNAs associated with incubation of heroin craving, including miR-485-5p, which was significantly downregulated following 21D forced abstinence in HH but not HL animals. We bidirectionally manipulated miR-485-5p in the OFC to demonstrate that miR-485-5p can regulate long-lasting heroin seeking behavior after extended forced abstinence. Proteomics analysis identified 45 proteins selectively regulated in the OFC of HH but not HL animals that underwent 21D forced abstinence, of which 7 were putative miR-485-5p target genes. Thus, the miR-485-5p pathway is dysregulated in animals with a phenotype of persistent heroin craving behavior and OFC miR-485-5p pathways may function to support long-lasting heroin seeking.

Indirect regulation of HIPPO pathway by miRNA mediates high-intensity intermittent exercise to ameliorate aging skeletal muscle function.

Exercise-induced microRNA (miRNA) and HIPPO pathways participate in the regulation of skeletal muscle plasticity but their underlying mechanisms remain unclear. We aimed to investigate the effect of high-intensity interval training (HIIT) on miRNA expression and the HIPPO pathway in the skeletal muscle of aging rats to determine its role in the amelioration of muscle aging. Thirty-six 18-month-old female rats were randomly divided into sedentary control (SED, n=12), moderate-intensity continuous training (MICT, n=12), and HIIT (n=12) groups, with continuous exercise for 8 months. Quantitative reverse transcription-polymerase chain reaction, immunoblotting, KEGG enrichment, and dual-luciferase assays were performed on the target skeletal muscle. Compared with the SED group, the MICT and HIIT groups showed a significant trend of improvement in Lee's index and grip strength and a marked increase in skeletal muscle mitochondrial function, apoptosis, antioxidant, and lipolysis-related protein expression. They also exhibited PI3K/AKT pathway activation and a decrease in expression of HIPPO pathway-related proteins; 20 miRNAs were differentially expressed and enriched in the exercise group compared with the SED group, including the HIPPO pathway and metabolic pathways. Further analysis of L6 cells confirmed that miR-182 may target PTEN, which indirectly regulates HIPPO signaling, but not Mob1. the combined application of HIIT and MICT increased the antioxidant and lipolytic capacities of skeletal muscle and improved atrophy of aging skeletal muscle; HIIT was more effective than MICT. This may be related to HIIT-mediated AKT pathway activation and HIPPO pathway inhibition by miRNAs (miR-486 and miR-182).

Exosomes mediated fibrogenesis in dilated cardiomyopathy through a MicroRNA pathway

Cardiac fibrosis is a hallmark in late-stage familial dilated cardiomyopathy (DCM) patients, although the underlying mechanism remains elusive. Cardiac exosomes (Exos) have been reported relating to fibrosis in ischemic cardiomyopathy. Thus, we investigated whether Exos secreted from the familial DCM cardiomyocytes could promote fibrogenesis. Using human iPSCs differentiated cardiomyocytes we isolated Exos of angiotensin II stimulation conditioned media from either DCM or control (CTL) cardiomyocytes. Of interest, cultured cardiac fibroblasts had increased fibrogenesis following exposure to DCM-Exos rather than CTL-Exos. Meanwhile, injecting DCM-Exos into mouse hearts enhanced cardiac fibrosis and impaired cardiac function. Mechanistically, we identified the upregulation of miRNA-218-5p in the DCM-Exos as a critical contributor to fibrogenesis. MiRNA-218-5p activated TGF-β signaling via suppression of TNFAIP3, a master inflammation inhibitor. In conclusion, our results illustrate a profibrotic effect of cardiomyocytes-derived Exos that highlights an additional pathogenesis pathway for cardiac fibrosis in DCM.

The microRNA pathway activation in insect cell model upon Autographa californica multiple nucleopolyhedrovirus infection

Background: The immune system of insects exerts fundamentally different antiviral mechanisms than mammals. MicroRNAs (miRNAs) play vital roles in developing insect antiviral immunity. MiRNAs expression profiles of insects changed significantly during baculovirus infection. Methods: Differential expression profiles of miRNAs in Spodoptera frugiperda were monitored by next-generation sequencing (NGS) and RT-qPCR during Autographa californica multiple nucleopolyhedrovirus (AcMNPV) infection. The transcription levels of genes were detected by RT-qPCR. The 50% tissue culture infective dose (TCID50) endpoint dilution assay was used to determine the proliferation of progeny virus. Results: NGS revealed that 49 miRNAs were differentially expressed in Sf9 cells, and 10 of them were significantly up- or down-regulated. Though RT-qPCR analysis, we observed the similar trends for the expression patterns of significantly differentially expressed miRNAs from NGS. Moreover, the transcription levels of core genes, Exportin5, Dicer1, and Argonaute1, in miRNA biogenesis pathways were significantly increased after AcMNPV infection. For five selected miRNAs, miR-34-5p could regulate the proliferation of baculovirus progeny virus and energy metabolism. Conclusion: The miRNAs biogenesis pathway in Sf9 cells plays an important role and may be stimulated to resist AcMNPV infection. This work provides evidence for the molecular mechanism of baculovirus-insect interaction and offers novel ideas and directions for green pest control technology.

Serum exosomal microRNA pathway activation in placenta accreta spectrum (PAS) pathophysiology and detection

Serum exosomal microRNA pathway activation in placenta accreta spectrum (PAS) pathophysiology and detection

Host microRNAs exhibit differential propensity to interact with SARS-CoV-2 and variants of concern

A significant number of SARS-CoV-2-infected individuals naturally overcome viral infection, suggesting the existence of a potent endogenous antiviral mechanism. As an innate defense mechanism, microRNA (miRNA) pathways in mammals have evolved to restrict viruses, besides regulating endogenous mRNAs. In this study, we systematically examined the complete repertoire of human miRNAs for potential binding sites on SARS-CoV-2 Wuhan-Hu-1, Beta, Delta, and Omicron. Human miRNA and viral genome interaction were analyzed using RNAhybrid 2.2 with stringent parameters to identify highly bonafide miRNA targets. Using publicly available data, we filtered for miRNAs expressed in lung epithelial cells/tissue and oral keratinocytes, concentrating on the miRNAs that target SARS-CoV-2 S protein mRNAs. Our results show a significant loss of human miRNA and SARS-CoV-2 interactions in Omicron (130 miRNAs) compared to Wuhan-Hu-1 (271 miRNAs), Beta (279 miRNAs), and Delta (275 miRNAs). In particular, hsa-miR-3150b-3p and hsa-miR-4784 show binding affinity for S protein of Wuhan strain but not Beta, Delta, and Omicron. Loss of miRNA binding sites on N protein was also observed for Omicron. Through Ingenuity Pathway Analysis (IPA), we examined the experimentally validated and highly predicted functional role of these miRNAs. We found that hsa-miR-3150b-3p and hsa-miR-4784 have several experimentally validated or highly predicted target genes in the Toll-like receptor, IL-17, Th1, Th2, interferon, and coronavirus pathogenesis pathways. Focusing on the coronavirus pathogenesis pathway, we found that hsa-miR-3150b-3p and hsa-miR-4784 are highly predicted to target MAPK13. Exploring miRNAs to manipulate viral genome/gene expression can provide a promising strategy with successful outcomes by targeting specific VOCs.

Structural and functional basis of mammalian microRNA biogenesis by Dicer

MicroRNA (miRNA) and RNA interference (RNAi) pathways rely on small RNAs produced by Dicer endonucleases. Mammalian Dicer primarily supports the essential gene-regulating miRNA pathway, but how it is specifically adapted to miRNA biogenesis is unknown. We show that the adaptation entails a unique structural role of Dicer's DExD/H helicase domain. Although mice tolerate loss of its putative ATPase function, the complete absence of the domain is lethal because it assures high-fidelity miRNA biogenesis. Structures of murine Dicer•-miRNA precursor complexes revealed that the DExD/H domain has a helicase-unrelated structural function. It locks Dicer in a closed state, which facilitates miRNA precursor selection. Transition to a cleavage-competent open state is stimulated by Dicer-binding protein TARBP2. Absence of the DExD/H domain or its mutations unlocks the closed state, reduces substrate selectivity, and activates RNAi. Thus, the DExD/H domain structurally contributes to mammalian miRNA biogenesis and underlies mechanistical partitioning of miRNA and RNAi pathways.

MiR-1249 on Endothelial Extracellular Vesicles Mediates Cigarette Smoke-Induced Pulmonary Hypertension by Inhibiting HDAC10 (Histone Deacetylase 10)-NFκB (Nuclear Factor κB)-CaSR (Calcium-Sensing Receptor) Cascade.

Overproduction of endothelial extracellular vesicles (eEVs) is correlated with pulmonary hypertension progression, but the precise mechanism remains largely unclear. MicroRNA-chip and real-time polymerase chain reaction were conducted to screen and validate microRNA profiles in blood plasma eEVs of rats and human with or without cigarette smoking. Pulmonary artery smooth muscle cells were cultured to study signaling pathways. Pulmonary hypertension phenotypes were evaluated in wild-type and calcium-sensing receptor knockout rats to identify the pathophysiological significance of the microRNA pathway. MicroR-1249 was predominant highly expressed in eEVs from plasma of rats exposed to cigarette smoking, and confirmed in eEVs from plasma of human smokers as well as in eEVs from cigarette smoke extract-treated pulmonary artery endothelial cells, but not in cigarette smoke extract-treated pulmonary artery smooth muscle cells. In cultured pulmonary artery smooth muscle cells, microR-1249 downregulated the expression of histone deacetylase 10, which in turn enhanced the acetylated form of NFκB (nuclear factor κB) level and its nuclear translocation leading to increased expression of calcium-sensing receptor. In rats, the repression of microR-1249 in eEVs by microR-1249 inhibitor, histone deacetylase 10 overexpression, or calcium-sensing receptor knockout profoundly inhibited the proliferative capacities and diminished apoptosis-resistance of pulmonary artery smooth muscle cells and pulmonary hypertension development in rats intravenously administrated with eEVs preparation from cigarette smoke extract-treated pulmonary artery endothelial cells. Cigarette smoke-enriched microR-1249 in endothelial extracellular vesicles facilitates the hyperproliferative and antiapoptotic status of pulmonary artery smooth muscle cells promoting pulmonary hypertension evolution through the inhibition of histone deacetylase 10-NFκB-calcium-sensing receptor cascade.

A Tale of Two Lobsters-Transcriptomic Analysis Reveals a Potential Gap in the RNA Interference Pathway in the Tropical Rock Lobster Panulirus ornatus.

RNA interference (RNAi) has been widely utilised in many invertebrate models since its discovery, and in a majority of instances presents as a highly efficient and potent gene silencing mechanism. This is emphasized in crustaceans with almost all taxa having the capacity to trigger effective silencing, with a notable exception in the spiny lobsters where repeated attempts at dsRNA induced RNAi have demonstrated extremely ineffective gene knockdown. A comparison of the core RNAi machinery in transcriptomic data from spiny lobsters (Panulirus ornatus) and the closely related slipper lobsters (Thenus australiensis, where silencing is highly effective) revealed that both lobsters possess all proteins involved in the small interfering and microRNA pathways, and that there was little difference at both the sequence and domain architecture level. Comparing the expression of these genes however demonstrated that T. australiensis had significantly higher expression in the transcripts encoding proteins which directly interact with dsRNA when compared to P. ornatus, validated via qPCR. These results suggest that low expression of the core RNAi genes may be hindering the silencing response in P. ornatus, and suggest that it may be critical to enhance the expression of these genes to induce efficient silencing in spiny lobsters.

Association between fine particulate matter and coronary heart disease: A miRNA microarray analysis

Several studies have reported an association between residential surrounding particulate matter with an aerodynamic diameter ≤2.5 μm (PM2.5) and coronary heart disease (CHD). However, the underlying biological mechanism remains unclear. To fill this research gap, this study enrolled a residentially stable sample of 942 patients with CHD and 1723 controls. PM2.5 concentration was obtained from satellite-based annual global PM2.5 estimates for the period 1998–2019. MicroRNA microarray and pathway analysis of target genes was performed to elucidate the potential biological mechanism by which PM2.5 increases CHD risk. The results showed that individuals exposed to high PM2.5 concentrations had higher risks of CHD than those exposed to low PM2.5 concentrations (odds ratio = 1.22, 95% confidence interval: 1.00, 1.47 per 10 μg/m3 increase in PM2.5). Systolic blood pressure mediated 6.6% of the association between PM2.5 and CHD. PM2.5 and miR-4726-5p had an interaction effect on CHD development. Bioinformatic analysis demonstrated that miR-4726-5p may affect the occurrence of CHD by regulating the function of RhoA. Therefore, individuals in areas with high PM2.5 exposure and relative miR-4726-5p expression have a higher risk of CHD than their counterparts because of the interaction effect of PM2.5 and miR-4726-5p on blood pressure.

Targeting the microRNA pathway core genes, Dicer 1 and Argonaute 1, negatively affects the survival and fecundity of Bemisia tabaci.

MicroRNAs (miRNAs) are small regulatory non-coding RNAs that are involved in a variety of biological processes such as immunity, cell signaling and development by regulating gene expression. The whitefly Bemisia tabaci is a polyphagous vector that transmits many plant viruses causing economic damage to crops worldwide. In this study, we characterized and analyzed the expression of the miRNA core genes Argonaute-1 (Ago1) and Dicer-1 (Dcr1) in B. tabaci and explored the effect of their silencing on the insect's fitness. Our results showed that Ago1 and Dcr1 are differentially expressed in different tissues and developmental stages of B. tabaci. To determine the function of the miRNA pathway in B. tabaci, we silenced Ago1 and Dcr1 using specific double-stranded RNAs to the genes. RNA interference (RNAi) of Ago1 and Dcr1 decreased the expression level of the core genes and reduced the abundance of Let-7 and miR-184 miRNAs. Silencing of the miRNA pathway core gene also negatively affected the biology of B. tabaci by reducing fertility, fecundity and survival of this insect pest. Together, our results showed that silencing the miRNA pathway core genes reduced the miRNA levels followed by reduced fecundity and survival of B. tabaci, which highlighted the importance of the miRNA pathway in this insect. The miRNA core genes are attractive targets for developing an RNAi-based strategy for targeting this notorious insect pest. © 2022 Society of Chemical Industry.

Epigenetic Profiling in the Saliva of Obese Pregnant Women.

Maternal obesity is associated with inflammation and oxidative stress, strongly impacting the intrauterine environment with detrimental consequences for both mother and offspring. The saliva is a non-invasive biofluid reflecting both local and systemic health status. This observational study aimed to profile the epigenetic signature in the saliva of Obese (OB) and Normal-Weight (NW) pregnant women. Sixteen NW and sixteen OB Caucasian women with singleton spontaneous pregnancies were enrolled. microRNAs were quantified by the OpenArray Platform. The promoter region methylation of Suppressor of Cytokine Signaling 3 (SOCS3) and Transforming Growth Factor Beta 1 (TGF-Beta1) was assessed by pyrosequencing. There were 754 microRNAs evaluated: 20 microRNAs resulted in being differentially expressed between OB and NW. microRNA pathway enrichment analysis showed a significant association with the TGF-Beta signaling pathway (miTALOS) and with fatty acids biosynthesis/metabolism, lysine degradation, and ECM–receptor interaction pathways (DIANA–miRPath). Both SOCS3 and TGF-Beta1 were significantly down-methylated in OB vs. NW. These results help to clarify impaired mechanisms involved in obesity and pave the way for the understanding of specific damaged pathways. The characterization of the epigenetic profile in saliva of pregnant women can represent a promising tool for the identification of obesity-related altered mechanisms and of possible biomarkers for early diagnosis and treatment of pregnancy-adverse conditions.

Epicardial histone deacetylase 3 promotes myocardial growth through a novel microRNA pathway

Establishment of the myocardial wall requires proper growth cues from nonmyocardial tissues. During heart development, the epicardium and epicardium‐derived cells (EPDCs) instruct myocardial growth by secreting essential factors including fibroblast growth factor 9 (FGF9) and insulin‐like growth factor 2 (IGF2). However, it is poorly understood how the epicardial secreted factors are regulated, in particular by chromatin modifications for myocardial formation. To understand whether and how histone deacetylase 3 (HDAC3) in the developing epicardium regulates myocardial growth, we deleted Hdac3 in the developing murine epicardium. Mutant hearts showed ventricular myocardial wall hypoplasia with reduction of EPDCs. The cultured embryonic cardiomyocytes with supernatants from Hdac3 knockout (KO) mouse epicardial cells (MECs) also showed decreased proliferation. Genome‐wide transcriptomic analysis revealed that Fgf9 and Igf2 were significantly down‐regulated in Hdac3 KO MECs. We further found that Fgf9 and Igf2 expression is dependent on HDAC3 deacetylase activity. The supplementation of FGF9 or IGF2 can rescue the myocardial proliferation defects treated by Hdac3 KO supernatant. Mechanistically, we identified that microRNA (miR)‐322 and miR‐503 were upregulated in Hdac3 KO MECs and Hdac3 epicardial KO hearts. Overexpression of miR‐322 or miR‐503 repressed FGF9 and IGF2 expression, while knockdown of miR‐322 or miR‐503 restored FGF9 and IGF2 expression in Hdac3 KO MECs. Our findings reveal a critical signaling pathway in which epicardial HDAC3 promotes compact myocardial growth by stimulating FGF9 and IGF2 through repressing miR‐322/miR‐503, providing novel insights in elucidating etiology of congenital heart defects, and conceptual strategies to promote myocardial regeneration.