miR-21-5p regulates mitochondrial respiration and lipid content in H9C2 cells

Protective activity of adipose-derived stem cell extracellular vesicles in ischemia and/or reperfusion

Increasing evidence of the significant clinical value of protection against ischemia/reperfusion injury has contributed to the realization of the independent importance of this approach in improving prognosis and reducing cardiovascular mortality. Extracellular vesicles (EVs) derived by adipose mesenchymal stem cells may mediate the paracrine effects of stem cells and provide regenerative and anti-inflammatory properties, which are enhanced by γ-aminobutyric acid. The protective effects on cardiac myocytes may result from the EV embarked by miR-21-5p, which is a target for thioredoxin-interacting protein, regulating the formation of thioredoxin-interacting protein-thioredoxin complexes and subsequently enhancing the antioxidant activity of thioredoxin. It has been found that γ-aminobutyric acid governs myocardial bioenergetics through suppressing inflammation and supporting mitochondrial structure. Finally, stem cell-based cell-free therapy based on adipose-derived stem cell EVs is considered a promising approach to individualized management of ischemia-induced cardiomyopathy.

From exosomes to mitochondria and myocardial infarction: Molecular insight and therapeutic challenge

Myocardial infarction (MI) remains a leading cause of mortality worldwide. Despite patients with MI benefit from timely reperfusion therapies, the rates of mortality and morbidity remain substantial, suggesting an enduring need for the development of new approaches. Molecular mechanisms underlying myocardial ischemic injury are associated with both cardiomyocytes and non-cardiomyocytes. Exosomes are nano-sized extracellular vesicles released by almost all eukaryotic cells. They facilitate the communication between various cells by transferring information via their cargo and altering different biological activities in recipient cells. Studies have created great prospects for therapeutic applications of exosomes in MI, as demonstrated through their beneficial effect on heart function and reducing ventricular remodeling in association with fibrosis, angiogenesis, apoptosis, and inflammation. Of note, myocardial ischemic injury is primarily due to restricted blood flow, reducing oxygen availability, and causing inefficient utilization of energy substrates. However, the impact of exosomes on cardiac energy metabolism has not been adequately investigated. Although exosomes have been engineered for targeted delivery to enhance clinical efficacy, challenges must be overcome to utilize them reliably in the clinic. In this review, we summarize the research progress of exosomes for MI with a focus on the known and unknown regarding the role of exosomes in energy metabolism in cardiomyocytes and non-cardiomyocytes; as well as potential research avenues of exosome-mitochondrial energy regulation as well as therapeutic challenges. We aim to help identify more efficient molecular targets that may promote the clinical application of exosomes.

Mesenchymal stem cell-derived exosomal mir-21-5p inhibits YAP1 expression and improves outcomes in myocardial infarction

BACKGROUND

Myocardial infarction (MI) remains a significant global health concern, characterized by cardiomyocyte apoptosis and adverse ventricular remodeling. Nevertheless, the interplay between exosomal miR-21-5p and Yes-associated protein 1 (YAP1) in the context of MI remains unexplored.

METHODS

Rat mesenchymal stem cells (MSCs) and H9c2 cardiomyocytes were cultured, characterized, and instrumental in our experiments. Exosomes were meticulously isolated, and their identity confirmed. The internalization of these exosomes by H9c2 cells was assessed, while RNA and protein expression were quantified using Quantitative Real-Time PCR and Western blot, respectively. MTT assay was implemented for cell viability, and apoptosis was evaluated via flow cytometric analysis. To elucidate gene interactions, we conducted microarray profiling of miRNA expression, dual luciferase reporter assays, and RNA Immunoprecipitation.

RESULTS

MSC-derived exosomes exhibited a remarkable capacity to attenuate hypoxia-induced inflammation and apoptosis in H9c2 cells. Notably, these exosomes significantly upregulated miR-21-5p levels within H9c2 cells, and the abrogation of miR-21-5p function abated their protective effects. Through computational analysis, we unveiled a miR-21-5p binding site in the 3'UTR of YAP1, which directly inhibited YAP1 expression. Importantly, the inhibition of YAP1 effectively reinstated the protective effects of exosomes in cells with impaired exosomal miR-21-5p.

CONCLUSION

This study underscores the pivotal role played by MSC-derived exosomes in safeguarding against MI, primarily by mediating the transfer of miR-21-5p, which targets YAP1 signaling pathways.

CLINICAL TRIAL NUMBER

N/A.

Glucocorticoid modulates oxidative and thermogenic function of rat brown adipose tissue and human brown adipocytes

Chronic and excessive glucocorticoid (GC) exposure can cause Cushing's syndrome, resulting in fat accumulation in selected body areas. Particularly in the brown adipose tissue (BAT), GC acts negatively, resulting in whitening of the tissue. We hypothesized that dysregulation of microRNAs by GC could be an additional mechanism to explain its negative actions in BAT. Male Wistar rats were divided into two groups: (1) Control sham and (2) GC group that was administered dexamethasone 6.25 mg/200 μL via osmotic pump implantation over 28 days. After this period, the animals were euthanized and BAT tissue was properly stored. Human fat cells treated with dexamethasone were used to translate the experimental results found in animals to human biology. GC-treated rat BAT presented with large lipid droplets, severely impaired thermogenic activation, and reduced glucose uptake measured by 18F-FDG PET/CT. GC exposure induced a reduction in the mitochondrial OXPHOS system and oxygen consumption. MicroRNA profiling of BAT revealed five top-regulated microRNAs and among them miR-21-5p was the most significantly upregulated in GC-treated rats compared to the control group. Although upregulation of miR-21-5p in the tissue, differentiated primary brown adipocytes from GC-treated rats had decreased miR-21-5p levels compared to the control group. To translate these results to the clinic, human brown adipocytes were treated with dexamethasone and miR-21-5p inhibitor. In human brown cells, inhibition of miR-21-5p increased brown adipocyte differentiation and prevented GC-induced glucose uptake, resulting in a lower glycolysis rate. In conclusion, high-dose GC therapy significantly impacts brown adipose tissue function, with a notable association between glucose uptake and miR-21-5p.

Ling-gui-zhu-gan promotes adipocytes browning via targeting the miR-27b/PRDM16 pathway in 3T3-L1 cells

Introduction: Obesity, a global epidemic, is caused by an imbalance between energy intake and expenditure. The induction of white adipose browning to increase heat production has emerged as a potential effective strategy to address obesity. Ling-gui-zhu-gan (LGZG), a traditional Chinese medicine formula, has been proved to achieve promising results to combat obesity and related metabolic diseases, yet the mechanisms remain largely unexplored. This study aimed to elucidate the anti-obesity properties and the mechanisms of LGZG by investigating its browning effect on 3T3-L1 adipocytes. Methods: LGZG-containing serum obtained by oral administration of LGZG to animals was added to 3T3-L1 adipocytes to simulate in vivo conditions. Results: The results showed that 49 compounds were identified in LGZG-containing serum by UHPLC-Q-Orbitrap HRMS, including compounds such as atractylenolides and polyporenic acid C, etc. LGZG-containing serum alleviated the lipid accumulation and decreased both intracellular and extracellular triglyceride contents in a dose-dependent manner. This reduction is accompanied by enhanced mitochondrial respiratory and heat production function. Mechanistically, LGZG-containing serum led to a decrease in miR-27b expression and an increase in the mRNA and protein levels of browning-related markers, including UCP1, PRDM16, PGC-1α, PPARγ, CTBP1, and CTBP2. Further investigation using miR-27b mimic transfection confirmed that miR-27b/PRDM16 pathway might be a potential mechanism by which LGZG-containing serum promotes browning of 3T3-L1 adipocytes. Discussion: These results underscore the therapeutic potential of LGZG in addressing obesity and its associated metabolic disorders through the promotion of adipose browning.

Activation of VGLL4 Suppresses Cardiomyocyte Maturational Hypertrophic Growth

From birth to adulthood, the mammalian heart grows primarily through increasing cardiomyocyte (CM) size, which is known as maturational hypertrophic growth. The Hippo-YAP signaling pathway is well known for regulating heart development and regeneration, but its roles in CM maturational hypertrophy have not been clearly addressed. Vestigial-like 4 (VGLL4) is a crucial component of the Hippo-YAP pathway, and it functions as a suppressor of YAP/TAZ, the terminal transcriptional effectors of this signaling pathway. To develop an in vitro model for studying CM maturational hypertrophy, we compared the biological effects of T3 (triiodothyronine), Dex (dexamethasone), and T3/Dex in cultured neonatal rat ventricular myocytes (NRVMs). The T3/Dex combination treatment stimulated greater maturational hypertrophy than either the T3 or Dex single treatment. Using T3/Dex treatment of NRVMs as an in vitro model, we found that activation of VGLL4 suppressed CM maturational hypertrophy. In the postnatal heart, activation of VGLL4 suppressed heart growth, impaired heart function, and decreased CM size. On the molecular level, activation of VGLL4 inhibited the PI3K-AKT pathway, and disrupting VGLL4 and TEAD interaction abolished this inhibition. In conclusion, our data suggest that VGLL4 suppresses CM maturational hypertrophy by inhibiting the YAP/TAZ-TEAD complex and its downstream activation of the PI3K-AKT pathway.

Extracellular Vesicles in Ovarian Cancer: From Chemoresistance Mediators to Therapeutic Vectors

Ovarian cancer (OC) remains the deadliest gynecological malignancy, with alarming projections indicating a 42% increase in new cases and a 51% rise in mortality by 2040. This review explores the challenges in OC treatment, focusing on chemoresistance mechanisms and the potential of extracellular vesicles (EVs) as drug delivery agents. Despite advancements in treatment strategies, including cytoreductive surgery, platinum-based chemotherapy, and targeted therapies, the high recurrence rate underscores the need for innovative approaches. Key resistance mechanisms include drug efflux, apoptosis disruption, enhanced DNA repair, cancer stem cells, immune evasion, and the complex tumor microenvironment. Cancer-associated fibroblasts and extracellular vesicles play crucial roles in modulating the tumor microenvironment and facilitating chemoresistance. EVs, naturally occurring nanovesicles, emerge as promising drug carriers due to their low toxicity, high biocompatibility, and inherent targeting capabilities. They have shown potential in delivering chemotherapeutics like doxorubicin, cisplatin, and paclitaxel, as well as natural compounds such as curcumin and berry anthocyanidins, enhancing therapeutic efficacy while reducing systemic toxicity in OC models. However, challenges such as low production yields, heterogeneity, rapid clearance, and inefficient drug loading methods need to be addressed for clinical application. Ongoing research aims to optimize EV production, loading efficiency, and targeting, paving the way for novel and more effective therapeutic strategies in OC treatment. Overcoming these obstacles is crucial to unlocking the full potential of EV-based therapies and improving outcomes for OC patients.

MicroRNA-21 modulates brown adipose tissue adipogenesis and thermogenesis in a mouse model of polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS), the most common endocrine disorder in premenopausal women, is associated with increased obesity, hyperandrogenism, and altered brown adipose tissue (BAT) thermogenesis. MicroRNAs play critical functions in brown adipocyte differentiation and maintenance. We aim to study the role of microRNA-21 (miR-21) in altered energy homeostasis and BAT thermogenesis in a PCOS mouse model of peripubertal androgen exposure.

METHODS

Three-week-old miR-21 knockout (miR21KO) or wild-type (WT) female mice were treated with dihydrotestosterone (DHT) or vehicle for 90 days. Body composition was determined by EchoMRI. Energy expenditure (EE), oxygen consumption (VO2), carbon dioxide production (VCO2), and respiratory exchange ratio (RER) were measured by indirect calorimetry. Androgen receptor (AR), and markers of adipogenesis, de novo lipogenesis, angiogenesis, extracellular matrix remodeling, and thermogenesis were quantified by RT-qPCR and/or Western-blot.

RESULTS

MiR-21 ablation attenuated DHT-mediated increase in body weight while having no effect on fat or BAT mass. MiR-21 ablation attenuated DHT-mediated BAT AR upregulation. MiR-21 ablation did not alter EE; however, miR21KO DHT-treated mice have reduced VO2, VCO2, and RER. MiR-21 ablation reversed DHT-mediated decrease in food intake and increase in sleep time. MiR-21 ablation decreased some adipogenesis (Adipoq, Pparγ, and Cebpβ) and extracellular matrix remodeling (Mmp-9 and Timp-1) markers expression in DHT-treated mice. MiR-21 ablation abolished DHT-mediated increases in thermogenesis markers Cpt1a and Cpt1b, while decreasing CIDE-A expression.

CONCLUSIONS

Our findings suggest that BAT miR-21 may play a role in regulating DHT-mediated thermogenic dysfunction in PCOS. Modulation of BAT miR-21 levels could be a novel therapeutic approach for the treatment of PCOS-associated metabolic derangements.

Mitochondrial microRNAs: New Emerging Players in Vascular Senescence and Atherosclerotic Cardiovascular Disease

MicroRNAs (miRNAs) are small non-coding RNAs that play an important role by controlling gene expression in the cytoplasm in almost all biological pathways. Recently, scientists discovered that miRNAs are also found within mitochondria, the energy-producing organelles of cells. These mitochondrial miRNAs, known as mitomiRs, can originate from the nuclear or mitochondrial genome, and they are pivotal in controlling mitochondrial function and metabolism. New insights indicate that mitomiRs may influence key aspects of the onset and progression of cardiovascular disease, especially concerning mitochondrial function and metabolic regulation. While the importance of mitochondria in cardiovascular health and disease is well-established, our understanding of mitomiRs' specific functions in crucial biological pathways, including energy metabolism, oxidative stress, inflammation, and cell death, is still in its early stages. Through this review, we aimed to delve into the mechanisms of mitomiR generation and their impacts on mitochondrial metabolic pathways within the context of vascular cell aging and atherosclerotic cardiovascular disease. The relatively unexplored field of mitomiR biology holds promise for future research investigations, with the potential to yield novel diagnostic tools and therapeutic interventions.

Glutamine supplementation improves the activity and immunosuppressive action of induced regulatory T cells in vitro and in vivo

BACKGROUND

Glutamine is crucial for the activation and efficacy of T cells, and may play a role in regulating the immune environment. This study aimed to investigate the potential role of glutamine in the activation and proliferation of induced regulatory T cells (iTregs).

METHODS

CD4+CD45RA+T cells were sorted from peripheral blood mononuclear cells and cultured to analyze iTreg differentiation. Glutamine was then added to the culture system to evaluate the effects of glutamine on iTregs by determining oxidative phosphorylation (OXPHOS), apoptosis, and cytokine secretion. Additionally, a humanized murine graft-versus-host disease (GVHD) model was constructed to confirm the efficacy of glutamine-treated iTregs in vivo.

RESULTS

After being cultured in vitro, glutamine significantly enhanced the levels of Foxp3, CTLA-4, CD39, CD69, IL-10, TGF-β, and Ki67 (CTLA-4, IL-10, TGF-β are immunosuppressive markers of iTregs) compared with that of the control iTregs (P < 0.05). Furthermore, the growth curve showed that the proliferative ability of glutamine-treated iTregs was better than that of the control iTregs (P < 0.01). Compared with the control iTregs, glutamine supplementation significantly increased oxygen consumption rates and ATP production (P < 0.05), significantly downregulated Annexin V and Caspase 3, and upregulated BCL2 (P < 0.05). However, GPNA significantly reversed the effects of glutamine (P < 0.05). Finally, a xeno-GVHD mouse model was successfully established to confirm that glutamine-treated iTregs increased the mice survival rate, delayed weight loss, and alleviated colon injury.

CONCLUSION

Glutamine supplementation can improve the activity and immunosuppressive action of iTregs, and the possible mechanisms by which this occurs are related to cell proliferation, apoptosis, and OXPHOS.

Human MicroRNAs Modulated by Diet: A Scoping Review

Because of their role in regulating and fine-tuning gene expression in the posttranscriptional period, microRNA (miRNA) may represent a mediating factor that connects diet and metabolic regulation. Given the vast number of miRNAs and that modulations in miRNA happen in response to a variety of stimuli, a comprehensive registry of miRNAs impacted by diet and the food items that modulate them, would have utility in the identification of miRNA complements for analysis of diet interventions and in helping to establish linkages between the specific impacts of diet components. A scoping literature search of online databases (PubMed, SCOPUS, EMBASE, and Web of Science) was performed. Only studies in human populations, those that used a diet intervention or meal challenge, and those that measured miRNA profiles in the same subject at multiple time points were included. Of the 6167 studies screened, only 25 met the study criteria and were included in the review. Seven studies examined miRNA following a meal challenge, whereas 18 investigated miRNA following a sustained diet intervention. The results demonstrated that miRNA are modulated following a variety of diet interventions and that intensity of miRNA response is greater in metabolically healthy subjects. Heterogeneity in the intensity and length of the diet intervention, the study populations being observed, and the methodology through which target miRNA are identified contribute to a lack of comparability across studies. The findings of this review highlight the need for more study of miRNA responsiveness to intake and provide recommendations for future research.

Comprehensive review for non-coding RNAs: From mechanisms to therapeutic applications

Non-coding RNAs (ncRNAs) are an assorted collection of transcripts that are not translated into proteins. Since their discovery, ncRNAs have gained prominence as crucial regulators of various biological functions across diverse cell types and tissues, and their abnormal functioning has been implicated in disease. Notably, extensive research has focused on the relationship between microRNAs (miRNAs) and human cancers, although other types of ncRNAs, such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), are also emerging as significant contributors to human disease. In this review, we provide a comprehensive summary of our current knowledge regarding the roles of miRNAs, lncRNAs, and circRNAs in cancer and other major human diseases, particularly cancer, cardiovascular, neurological, and infectious diseases. Moreover, we discuss the potential utilization of ncRNAs as disease biomarkers and as targets for therapeutic interventions.

Silencing METTL14 alleviates liver injury in non-alcoholic fatty liver disease by regulating mitochondrial homeostasis

Mitochondrial dysfunction is an important pathogenic factor in non-alcoholic fatty liver disease (NAFLD). Methyltransferase-like 14 (METTL14) has been implicated in mitochondrial fission processes. This research aimed to investigate the mechanism of METTL14 in the mitochondrial function of NAFLD. We first established NAFLD mouse models and cell models, recording body and liver weights and examining pathological changes in liver tissues. Subsequently, serum levels of liver function indices (aspartate aminotransferase [AST], alanine aminotransferase [ALT], total cholesterol [TC], and triglycerides [TG]), inflammatory markers (tumor necrosis factor-alpha [TNF-α], interleukin [IL]-6, and IL-1β), and mitochondrial dysfunction indicators (fission 1 protein [Fis1], dynamin-related protein 1 [Drp1], mitofusin 2 [Mfn2], SID1 transmembrane family member 2 [SIDT2], and mitochondrial membrane potential [MMP]) in the liver and cells were evaluated. The N6-methyladenosine (m6A) modification level of primary microRNA (pri-miRNA) and m6A enrichment on pri-miR-34a were quantified. Co-immunoprecipitation and dual-luciferase reporter gene assays were utilized to validate gene interactions. Our findings revealed highly elevated METTL14 expression in NAFLD mouse and cell models. Silencing METTL14 reduced weight gain and mitigated adverse liver function indices, inflammation, hepatic steatosis, and structural damage in NAFLD mice. It also led to a decrease in Fis1/Drp1 levels and an increase in MMP/Mfn2 in the liver and cells. Moreover, METTL14 increased the m6A level, promoting the binding of DiGeorge syndrome critical region 8 (DGCR8) to pri-miR-34a, which enhanced miR-34a-5p expression. Databases and dual-luciferase reporter gene assays indicated that miR-34a-5p could suppress SIDT2 expression. The overexpression of miR-34a-5p or inhibition of SIDT2 expression negated the alleviative effects of METTL14 silencing on mitochondrial homeostasis imbalance. In conclusion, METTL14, through m6A modification, modulates the miR-34a-5p/SIDT2 axis, impairing mitochondrial homeostasis in NAFLD.

Follicular fluid exosomes inhibit expression of BTG2 and promote glucose uptake in granulosa cells by delivering miR-21-5p

Glucose metabolism in granulosa cells (GCs) is essential for follicle development and oocyte maturation. Porcine follicular fluid exosomes promote the proliferation of porcine GCs and the synthesis of steroid hormones. However, their role in regulating glucose uptake in GCs is unclear. The objective of this study was to elucidate the effects of porcine follicular fluid exosomes on glucose uptake in porcine GCs and the intrinsic mechanisms involved. First, transcriptome sequencing revealed that glucose metabolism-related pathways were altered in GCs treated with follicular fluid exosomes. Next, in vitro culture experiments showed that glucose uptake was increased and the IRS1/AKT signaling pathway was activated in GCs after treatment with follicular fluid exosomes. Finally, miRNA sequencing of follicular fluid exosomes revealed that miR-21-5p was the most abundant miRNA. Subsequent investigations indicated that miR-21-5p promoted glucose uptake in GCs by targeting BTG2, which activated the IRS1/AKT signaling pathway. In conclusion, the findings of this study indicate that porcine follicular fluid exosomes promote glucose uptake in porcine GCs by delivering miR-21-5p, which inhibits the expression of BTG2, activating the IRS1/AKT signaling pathway.

SIRT6 activates PPARα to improve doxorubicin-induced myocardial cell aging and damage

The Sirtuins family, formally known as the Silent Information Regulator Factors, constitutes a highly conserved group of histone deacetylases. Recent studies have illuminated SIRT6's role in doxorubicin (DOX)-induced oxidative stress and apoptosis within myocardial cells. Nevertheless, the extent of SIRT6's impact on DOX-triggered myocardial cell aging and damage remains uncertain, with the associated mechanisms yet to be fully understood. In our research, we examined the influence of SIRT6 on DOX-induced cardiomyocyte senescence using β-galactosidase and γ-H2AX staining. Additionally, we gauged the mRNA expression of senescence-associated genes, namely p16, p21, and p53, through Real-time PCR. Employing ELISA assay kits, MDA, and total SOD activity assay kits, we measured inflammatory factors TNF-α, IL-6, and IL-1β, alongside oxidative stress-related indicators. The results unequivocally indicated that SIRT6 overexpression robustly inhibited DOX-induced cardiomyocyte senescence. Furthermore, we established that SIRT6 overexpression suppressed the inflammatory response and oxidative stress induced by DOX in cardiomyocytes. Conversely, silencing SIRT6 exacerbated DOX-induced cardiomyocyte injury. Our investigations further unveiled that SIRT6 upregulated the expression of genes CD36, CPT1, LCAD, MCAD associated with fatty acid oxidation through its interaction with PPARα, thereby exerting anti-aging effects. In vivo, the overexpression of SIRT6 was observed to restore DOX-induced declines in EF and FS to normal levels in mice. Echocardiography and HE staining revealed the restoration of cardiomyocyte alignment, affording protection against DOX-induced myocardial senescence and injury. The findings from this study suggest that SIRT6 holds significant promise as a therapeutic target for mitigating DOX-induced cardiomyopathy.

Icariin alleviates high-fat diet-induced nonalcoholic fatty liver disease via up-regulating miR-206 to mediate NF-κB and MAPK pathways

Nonalcoholic fatty liver disease (NAFLD) is an abnormal lipid accumulation disease in hepatocytes. The existing drugs for NAFLD have some side effects, so new therapeutic agents are required to be explored. In this study, the effect and mechanism of icariin (ICA) on high-fat diet-induced NAFLD were investigated. Firstly, a high-fat diet was used to construct a NAFLD rat model and HepG2 cells were treated with 1 mM free fatty acid (FFA). After ICA treatment, the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBil), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were measured; liver injury and lipid deposition were observed by H&E and Oil Red O staining; interleukin-1β (IL-1β), IL-12, and IL-6 were measured by enzyme-linked immunosorbent assay. Additionally, qRT-PCR and western blot were performed to detect miR-206 expression and NF-κB/MAPK pathway-related protein expression in liver tissues and cells. After a variety of trials, we discovered that compared with the NAFLD group, ICA significantly reduced ALT, AST, TBil, TG, TC, and LDL-C levels and increased HDL-C levels, and improved liver tissue injury and lipid deposition. Moreover, ICA reduced IL-1β, IL-12, and IL-6 levels in liver tissues and cells as well as inhibited MAPK and NF-κB-related protein expression in the liver tissues. Notably, ICA could significantly increase miR-206 expression in liver tissues and cells. Further experiments confirmed that inhibition of miR-206 was able to reverse the effect of ICA on NAFLD. In conclusion, ICA can alleviate NAFLD by upregulating miR-206 to mediate NF-κB and MAPK pathways.

[Lithocholic acid decreases mRNA stability of nuclear receptor PPARα by upregulating miR-21 expression in hepatoma HepG2 cells]

OBJECTIVE

To investigate the regulatory effects of lithocholic acid (LCA) on nuclear receptor peroxisome proliferatoractivated receptor-alpha (PPARα) mRNA stability at the post-transcriptional level.

METHODS

PPARα 3'UTR luciferase reporter gene vectors were constructed and transfected into HepG2 cells to observe the changes in cellular luciferase activity in response to LCA treatments. Bioinformatic prediction and miRNA PCR array technique were used to identify the differentially expressed miRNAs induced by LCA and their potential binding sites on the 3'UTR. The binding sites (Mut1, Mut2 and Mut1+Mut2) were mutated to compare the changes in cellular luciferase activity following LCA treatment. Western blotting and RTqPCR were used to detect the activated signaling pathway and the expression levels of its downstream transcription factors in LCA-treated cells. The changes in PPARα protein expression level were detected in the cells following overexpression of the transcription factors.

RESULTS

Treatment with 100 μmol/L LCA significantly reduced luciferase activity of PPARα 3'UTR1 and 3'UTR2 in HepG2 cells by more than 50% (P<0.01) and induced significant upregulation of miR-21 and miR-22, especially the former (by 2.35 folds, P<0.05). Two predicted miR-21-binding sites in the 3'UTR1 were mutated to construct Mut1, Mut2 and Mut1+Mut2 reporter gene vectors. LCA treatment down-regulated 3'UTR1 luciferase activity by 51%, while Mut1, Mut2, and Mut1+Mut2 were down-regulated by 37%, 39%, and 13%, respectively. LCA caused ERK1/2 phosphorylation and activation of the ERK1/2 signaling pathway, and treatment with 100 μmol/L LCA upregulated the expression of transcription factor early growth response 1 (EGR1) by 5.83 folds (P<0.01). Transient overexpression of EGR1 significantly decreased cellular PPARα protein levels (P<0.05).

CONCLUSION

LCA reduces PPARα mRNA stability and thus decreases PPARα mRNA and protein expressions in hepatocytes by activating the ERK1/2 signaling pathway and upregulating EGR1 and miR-21, which targets 3'UTR regulatory region of PPARα mRNA.

Strain Variation Can Significantly Modulate the miRNA Response to Zika Virus Infection

Zika virus (ZIKV) is a mosquito-transmitted virus that has emerged as a major public health concern due to its association with neurological disorders in humans, including microcephaly in fetuses. ZIKV infection has been shown to alter the miRNA profile in host cells, and these changes can contain elements that are proviral, while others can be antiviral in action. In this study, the expression of 22 miRNAs in human A549 cells infected with two different ZIKV isolates was investigated. All of the investigated miRNAs showed significant changes in expression at at least one time point examined. Markedly, 18 of the miRNAs examined showed statistically significant differences in expression between the two strains examined. Four miRNAs (miR-21, miR-34a, miR-128 and miR-155) were subsequently selected for further investigation. These four miRNAs were shown to modulate antiviral effects against ZIKV, as downregulation of their expression through anti-miRNA oligonucleotides resulted in increased virus production, whereas their overexpression through miRNA mimics reduced virus production. However, statistically significant changes were again seen when comparing the two strains investigated. Lastly, candidate targets of the miRNAs miR-34a and miR-128 were examined at the level of the mRNA and protein. HSP70 was identified as a target of miR-34a, but, again, the effects were strain type-specific. The two ZIKV strains used in this study differ by only nine amino acids, and the results highlight that consideration must be given to strain type variation when examining the roles of miRNAs in ZIKV, and probably other virus infections.

Urine-derived stem cells in neurological diseases: current state-of-the-art and future directions

Stem cells have potential applications in the field of neurological diseases, as they allow for the development of new biological models. These models can improve our understanding of the underlying pathologies and facilitate the screening of new therapeutics in the context of precision medicine. Stem cells have also been applied in clinical tests to repair tissues and improve functional recovery. Nevertheless, although promising, commonly used stem cells display some limitations that curb the scope of their applications, such as the difficulty of obtention. In that regard, urine-derived cells can be reprogrammed into induced pluripotent stem cells (iPSCs). However, their obtaining can be challenging due to the low yield and complexity of the multi-phased and typically expensive differentiation protocols. As an alternative, urine-derived stem cells (UDSCs), included within the population of urine-derived cells, present a mesenchymal-like phenotype and have shown promising properties for similar purposes. Importantly, UDSCs have been differentiated into neuronal-like cells, auspicious for disease modeling, while overcoming some of the shortcomings presented by other stem cells for these purposes. Thus, this review assesses the current state and future perspectives regarding the potential of UDSCs in the ambit of neurological diseases, both for disease modeling and therapeutic applications.

miR-21-5p inhibits the growth of brain glioma cells through regulating the glycolysis mediated by PFKFB2

Brain glioma is a common gynecological tumor. MicroRNA (miRNA) plays a very important role in the pathogenesis and development of tumors. It was found that glycolysis played important regulatory roles in tumor growth. The present study aims to investigate the expression pattern of miR-21-5p in brain glioma cells. We examined miR-21-5p and PFKFB2 levels in brain glioma cells via qRT-PCR. Then we performed CCK-8 and Transwell migration assays and determined glucose uptake and lactose production to unveil the properties of miR-21-5p in invasion, cell viability, along with glycolysis in brain glioma cells. Luciferase activity assay was implemented to elucidate if PFKFB2 was a miR-21-5p target gene. Western blotting and qRT-PCR were executed to further validate that miR-21-5p targeted PFKFB2. We repeated these functional assays to observe whether miR-21-5p could impede the function of PFKFB2. qRT-PCR signified that miR-21-5p was elevated in brain glioma tissues in contrast to matching adjacent normal tissues. Functional assays disclosed that elevation of miR-21-5p promoted cell viability, invasion, together with glycolysis. Luciferase assay indicated that PFKFB2 was a miR-21-5p target gene. Moreover, miR-21-inhibit could hinder cell viability, invasion, and glycolysis triggered by overexpression of PFKFB2 in brain glioma cells. miR-21-5p level is elevated in brain glioma and can impede brain glioma cell growth via regulating the glycolysis mediated by PFKFB2, thus is a potential target of treating brain glioma.

Mesenchymal Stem Cell-Derived Exosomal Noncoding RNAs as Alternative Treatments for Myocardial Ischemia-Reperfusion Injury: Current Status and Future Perspectives

Ischemic cardiomyopathy is treated mainly with thrombolytic drugs, percutaneous coronary intervention, and coronary artery bypass grafting to recanalize blocked vessels. Myocardial ischemia-reperfusion injury (MIRI) is an unavoidable complication of obstructive revascularization. Compared with those of myocardial ischemic injury, few effective therapeutic options are available for MIRI treatment. The pathophysiological mechanisms of MIRI involve the inflammatory response, the immune response, oxidative stress, apoptosis, intracellular Ca2+ overload, and cardiomyocyte energy metabolism. These mechanisms exacerbate MIRI. Mesenchymal stem cell-derived exosomes (MSC-EXOs) can alleviate MIRI through these mechanisms and, to some extent, prevent the limitations caused by direct MSC administration. Therefore, using MSC-EXOs instead of MSCs to treat MIRI is a potentially beneficial cell-free treatment strategy. In this review, we describe the mechanism of action of MSC-EXO-derived noncoding RNAs in the treatment of MIRI and discuss the advantages and limitations of this strategy, as well as possible future research directions.

Oxygen consumption rate to evaluate mitochondrial dysfunction and toxicity in cardiomyocytes

The increase in the types and complexity of diseases has led to significant advances in diagnostic techniques and the availability of effective therapies. Recent studies have focused on the role of mitochondrial dysfunction in the pathogenesis of cardiovascular diseases (CVDs). Mitochondria are important organelles in cells that generate energy. Besides the production of adenosine triphosphate (ATP), the energy currency of cells, mitochondria are also involved in thermogenesis, control of intracellular calcium ions (Ca2+), apoptosis, regulation of reactive oxygen species (ROS), and inflammation. Mitochondrial dysfunction has been implicated in several diseases including cancer, diabetes, some genetic diseases, and neurogenerative and metabolic diseases. Furthermore, the cardiomyocytes of the heart are rich in mitochondria due to the large energy requirement for optimal cardiac function. One of the main causes of cardiac tissue injuries is believed to be mitochondrial dysfunction, which occurs via complicated pathways which have not yet been completely elucidated. There are various types of mitochondrial dysfunction including mitochondrial morphological change, unbalanced levels of substances to maintain mitochondria, mitochondrial damage by drugs, and mitochondrial deletion and synthesis errors. Most of mitochondrial dysfunctions are linked with symptoms and diseases, thus we focus on parts of mitochondrial dysfunction about fission and fusion in cardiomyocytes, and ways to understand the mechanism of cardiomyocyte damage by detecting oxygen consumption levels in the mitochondria.

Abnormalities of glucose and lipid metabolism in myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury is a common condition in cardiovascular diseases, and the mechanism of its occurrence involves multiple complex metabolic pathways and signaling pathways. Among these pathways, glucose metabolism and lipid metabolism play important roles in regulating myocardial energy metabolism. Therefore, this article focuses on the roles of glucose metabolism and lipid metabolism in myocardial ischemia-reperfusion injury, including glycolysis, glucose uptake and transport, glycogen metabolism and the pentose phosphate pathway; and triglyceride metabolism, fatty acid uptake and transport, phospholipid metabolism, lipoprotein metabolism, and cholesterol metabolism. Finally, due to the different alterations and development of glucose metabolism and lipid metabolism in myocardial ischemia-reperfusion, there are also complex interregulatory relationships between them. In the future, modulating the equilibrium between glucose metabolism and lipid metabolism in cardiomyocytes and ameliorating aberrations in myocardial energy metabolism represent highly promising novel strategies for addressing myocardial ischemia-reperfusion injury. Therefore, a comprehensive exploration of glycolipid metabolism can offer novel theoretical and clinical insights into the prevention and treatment of myocardial ischemia-reperfusion injury.

Inhibiting CDK4/6 in pancreatic ductal adenocarcinoma via microRNA-21

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies, with a 5-year survival rate of 5-10 %. The high mortality rate is due to the asymptomatic progression of clinical features in metastatic stages of the disease, which renders standard therapeutic options futile. PDAC is characterised by alterations in several genes that drive carcinogenesis and limit therapeutic response. The two most common genetic aberrations in PDAC are the mutational activation of KRAS and loss of the tumour suppressor CDK inhibitor 2A (CDKN2A), which culminate the activation of the cyclin-dependent kinase 4 and 6 (CDK4/6), that promote G1 cell cycle progression. Therapeutic strategies focusing on the CDK4/6 inhibitors such as palbociclib (PD-0332991) may potentially improve outcomes in this malignancy. MicroRNAs (miRs/miRNAs) are small endogenous non-coding RNA molecules associated with cellular proliferation, invasion, apoptosis, and cell cycle. Primarily, miR-21 promotes cell proliferation and a higher proportion of PDAC cells in the S phase, while knockdown of miR-21 has been linked to cell cycle arrest at the G2/M phase and inhibition of cell proliferation. In this study, using a CRISPR/Cas9 loss-of-function screen, we individually silenced the expression of miR-21 in two PDAC cell lines and in combination with PD-0332991 treatment, we examined the synergetic mechanisms of CDK4/6 inhibitors and miR-21 knockouts (KOs) on cell survival and death. This combination reduced cell proliferation, cell viability, increased apoptosis and G1 arrest in vitro. We further analysed the mitochondrial respiration and glycolysis of PDAC cells; then assessed the protein content of these cells and revealed numerous Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways associated with PD-0332991 treatment and miR-21 knocking out. Our results demonstrate that combined targeting of CDK4/6 and silencing of miR-21 represents a novel therapeutic strategy in PDAC.

Non-coding RNAs regulating mitochondrial function in cardiovascular diseases

Cardiovascular disease (CVD) is the leading cause of disease-related death worldwide and a significant obstacle to improving patients' health and lives. Mitochondria are core organelles for the maintenance of myocardial tissue homeostasis, and their impairment and dysfunction are considered major contributors to the pathogenesis of various CVDs, such as hypertension, myocardial infarction, and heart failure. However, the exact roles of mitochondrial dysfunction involved in CVD pathogenesis remain not fully understood. Non-coding RNAs (ncRNAs), particularly microRNAs, long non-coding RNAs, and circular RNAs, have been shown to be crucial regulators in the initiation and development of CVDs. They can participate in CVD progression by impacting mitochondria and regulating mitochondrial function-related genes and signaling pathways. Some ncRNAs also exhibit great potential as diagnostic and/or prognostic biomarkers as well as therapeutic targets for CVD patients. In this review, we mainly focus on the underlying mechanisms of ncRNAs involved in the regulation of mitochondrial functions and their role in CVD progression. We also highlight their clinical implications as biomarkers for diagnosis and prognosis in CVD treatment. The information reviewed herein could be extremely beneficial to the development of ncRNA-based therapeutic strategies for CVD patients.

Palmitate-Induced Cardiac Lipotoxicity Is Relieved by the Redox-Active Motif of SELENOT through Improving Mitochondrial Function and Regulating Metabolic State

Cardiac lipotoxicity is an important contributor to cardiovascular complications during obesity. Given the fundamental role of the endoplasmic reticulum (ER)-resident Selenoprotein T (SELENOT) for cardiomyocyte differentiation and protection and for the regulation of glucose metabolism, we took advantage of a small peptide (PSELT), derived from the SELENOT redox-active motif, to uncover the mechanisms through which PSELT could protect cardiomyocytes against lipotoxicity. To this aim, we modeled cardiac lipotoxicity by exposing H9c2 cardiomyocytes to palmitate (PA). The results showed that PSELT counteracted PA-induced cell death, lactate dehydrogenase release, and the accumulation of intracellular lipid droplets, while an inert form of the peptide (I-PSELT) lacking selenocysteine was not active against PA-induced cardiomyocyte death. Mechanistically, PSELT counteracted PA-induced cytosolic and mitochondrial oxidative stress and rescued SELENOT expression that was downregulated by PA through FAT/CD36 (cluster of differentiation 36/fatty acid translocase), the main transporter of fatty acids in the heart. Immunofluorescence analysis indicated that PSELT also relieved the PA-dependent increase in CD36 expression, while in SELENOT-deficient cardiomyocytes, PA exacerbated cell death, which was not mitigated by exogenous PSELT. On the other hand, PSELT improved mitochondrial respiration during PA treatment and regulated mitochondrial biogenesis and dynamics, preventing the PA-provoked decrease in PGC1-α and increase in DRP-1 and OPA-1. These findings were corroborated by transmission electron microscopy (TEM), revealing that PSELT improved the cardiomyocyte and mitochondrial ultrastructures and restored the ER network. Spectroscopic characterization indicated that PSELT significantly attenuated infrared spectral-related macromolecular changes (i.e., content of lipids, proteins, nucleic acids, and carbohydrates) and also prevented the decrease in membrane fluidity induced by PA. Our findings further delineate the biological significance of SELENOT in cardiomyocytes and indicate the potential of its mimetic PSELT as a protective agent for counteracting cardiac lipotoxicity.

Quercetin and Its Derivative Counteract Palmitate-Dependent Lipotoxicity by Inhibiting Oxidative Stress and Inflammation in Cardiomyocytes

Cardiac lipotoxicity plays an important role in the pathogenesis of obesity-related cardiovascular disease. The flavonoid quercetin (QUE), a nutraceutical compound that is abundant in the "Mediterranean diet", has been shown to be a potential therapeutic agent in cardiac and metabolic diseases. Here, we investigated the beneficial role of QUE and its derivative Q2, which demonstrates improved bioavailability and chemical stability, in cardiac lipotoxicity. To this end, H9c2 cardiomyocytes were pre-treated with QUE or Q2 and then exposed to palmitate (PA) to recapitulate the cardiac lipotoxicity occurring in obesity. Our results showed that both QUE and Q2 significantly attenuated PA-dependent cell death, although QUE was effective at a lower concentration (50 nM) when compared with Q2 (250 nM). QUE decreased the release of lactate dehydrogenase (LDH), an important indicator of cytotoxicity, and the accumulation of intracellular lipid droplets triggered by PA. On the other hand, QUE protected cardiomyocytes from PA-induced oxidative stress by counteracting the formation of malondialdehyde (MDA) and protein carbonyl groups (which are indicators of lipid peroxidation and protein oxidation, respectively) and intracellular ROS generation, and by improving the enzymatic activities of catalase and superoxide dismutase (SOD). Pre-treatment with QUE also significantly attenuated the inflammatory response induced by PA by reducing the release of key proinflammatory cytokines (IL-1β and TNF-α). Similar to QUE, Q2 (250 nM) also significantly counteracted the PA-provoked increase in intracellular lipid droplets, LDH, and MDA, improving SOD activity and decreasing the release of IL-1β and TNF-α. These results suggest that QUE and Q2 could be considered potential therapeutics for the treatment of the cardiac lipotoxicity that occurs in obesity and metabolic diseases.

MicroRNAs target the PI3K/Akt/p53 and the Sirt1/Nrf2 signaling pathways in doxorubicin-induced cardiotoxicity

Doxorubicin (DOX) is used as a chemotherapeutic agent in the treatment of solid tumors. Irreversible cardiotoxicity is the major limitation in the clinical use of DOX. Several microRNAs (miRNAs) with diversified functions are identified that participate in exacerbating or suppressing DOX-induced cardiac damage. The miRNAs are small noncoding regulatory RNAs that modify the expression of the native genes. Studies have demonstrated that miRNAs by modifying the expression of proteins such as PTEN, Akt, and survivin can affect DOX-induced cardiac apoptosis. Moreover, miRNAs can modulate cardiac oxidative stress in DOX treatment through the posttranscriptional regulation of Sirt1, p66shc, and Nrf2 expressions. This manuscript has reviewed the regulation of the PI3K/Akt/p53 and the Sirt1/Nrf2 pathways by miRNAs in DOX-induced cardiotoxicity.

MiR-21-5p protects against ischemic stroke by targeting IL-6R

Background

Ischemic stroke is a brain dysfunction disease caused by vascular obstruction. The expression of many kinds of microRNAs (miRNAs) is related to ischemic stroke. MiRNA has the ability to reduce or save ischemic injury. Therefore, we aimed to explore the protective miRNA in the ischemia-reperfusion process.

Methods

The Gene Expression Omnibus (GEO) peripheral RNA sequencing (RNA-seq) datasets of ischemic stroke patients were analyzed to search for differentially expressed miRNAs in the ischemia-reperfusion process. The expression level of miRNA in 60 patients with ischemic stroke and 23 age-matched healthy control inpatients was tested by quantitative reverse transcription polymerase chain reaction (qRT-PCR). The significantly changed miRNAs were verified through comparison of the peripheral blood of healthy people and patients of the hospital. The in-vitro ischemia-reperfusion model was established through oxygen-glucose deprivation (OGD) treated HEMC-1 cells. The cell viabilities and cell apoptosis are detected by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, respectively. Apoptosis-related proteins including Bcl-2, Bax, caspase-3, and caspase-9 expression levels were verified by western blot. Predict the combination of hsa-miR-21-5p and interleukin-6 receptor (IL-6R) through TargetScan database, clone the 2964-2961 site of IL-6R-3'-untranslated region (3'-UTR), establish IL-6R-3'-UTR and IL-6R-3'-UTR mutant plasmids, copy and clone wild type and mutant IL-6R-3'-UTR into luciferase report vector pGL3 respectively, and detect the activity of luciferase. The expression of hsa-miR-21-5p was regulated by using hsa-miR-21-5p mimic and hsa-miR-21-5p inhibitor.

Results

Through RNA-seq analysis, it was revealed that "hsa-miR-548ar-3p", "hsa-miR-651-5p", "hsa-miR-142-3p", "hsa-miR-21-5p", and "hsa-miR-30e-5p" were notably lower in ischemia patients, and that "hsa-miR-21-5p" was significantly decreased in the peripheral blood of hospital patients. Luciferase assay showed that hsa-miR-21-5p could directly bind to the 3'-UTR of the IL-6R gene and inhibit IL-6R translation; the level of IL-6R was also elevated in patients. In the OGD-treated HMEC-1 cells, overexpressed hsa-miR-21-5p mimic could enhance cell viabilities and decrease cell apoptosis. Moreover, IL-6R overexpression could reduce the protective effects of hsa-miR-21-5p.

Conclusions

In the peripheral blood of ischemia patients, hsa-miR-21-5p is significantly decreased and IL-6R is elevated. The "hsa-miR-21-5p" could bind to the IL-6R gene and suppress IL-6R expression, thus alleviating the damage of OGD treatment in HMEC-1 cells.

Mitochondrial microRNAs Are Dysregulated in Patients with Fabry Disease

Fabry disease (FD) is a lysosomal storage disorder caused by mutations in the gene for α-galactosidase A, inducing a progressive accumulation of globotriaosylceramide (GB3) and its metabolites in different organs and tissues. GB3 deposition does not fully explain the clinical manifestations of FD, and other pathogenetic mechanisms have been proposed, requiring the identification of new biomarkers for monitoring FD patients. Emerging evidence suggests the involvement of mitochondrial alterations in FD. Here, we propose mitochondrial-related microRNAs (miRs) as potential biomarkers of mitochondrial involvement in FD. Indeed, we demonstate that miRs regulating different aspects of mitochondrial homeostasis including expression and assembly of respiratory chain, mitogenesis, antioxidant capacity, and apoptosis are consistently dysregulated in FD patients. Our data unveil a novel noncoding RNA signature of FD patients, indicating mitochondrial-related miRs as new potential pathogenic players and biomarkers in FD. SIGNIFICANCE STATEMENT: This study demonstrates for the first time that a specific signature of circulating mitochondrial miRs (mitomiRs) is dysregulated in FD patients. MitomiRs regulating fundamental aspects of mitochondrial homeostasis and fitness, including expression and assembly of the respiratory chain, mitogenesis, antioxidant capacity, and apoptosis are significantly dysregulated in FD patients. Taken together, these new findings introduce mitomiRs as unprecedented biomarkers of FD and point at mitochondrial dysfunction as a novel potential mechanistic target for therapeutic approaches.

Profiles of lipid, protein and microRNA expression in exosomes derived from intestinal epithelial cells after ischemia-reperfusion injury in a cellular hypoxia model

Intestinal ischemia-reperfusion injury leads to proinflammatory responses via gut-derived mediators, and accumulating evidence suggests that exosomes secreted by intestinal epithelial cells are involved in the development of systemic inflammation. Studies have reported changes in protein, lipid, and microRNA (miRNA) expression; however, considering the different experimental conditions, information on the relationships among these biomolecules remains insufficient. The aim of this study was to elucidate the multiple changes that simultaneously occur in exosomes after ischemic stimulation. Here, differentiated human intestinal Caco-2 cells were exposed to 95% air (normoxia group) or 5% O2 (hypoxia group) for 6 h. Cells in each group were subsequently incubated for 24 h in an atmosphere of 5% CO2 plus 95% air. The conditioned medium of each group was collected for isolating intestinal epithelial cell-derived exosomes. Together with proteome analyses, lipid analyses, and miRNA quantification, biological functional assays were performed using monocytic NF-κB reporter cells. Lipid metabolism-related protein expression was upregulated, miRNA levels were slightly altered, and unsaturated fatty acid-containing lysophosphatidylcholine concentration increased after hypoxia and reoxygenation injury; this suggested that the changes in exosomal components associated with ischemia-reperfusion injury activates inflammation, including the NF-κB pathway. This study elucidated the multiple changes that co-occur in exosomes after ischemic stimulation and partially clarified the mechanism underlying exosome-mediated inflammation after intestinal ischemic recanalization.

MicroRNAs as immune regulators and biomarkers in tuberculosis

Tuberculosis (TB), which is caused by Mycobacterium tuberculosis (Mtb), is one of the most lethal infectious disease worldwide, and it greatly affects human health. Some diagnostic and therapeutic methods are available to effectively prevent and treat TB; however, only a few systematic studies have described the roles of microRNAs (miRNAs) in TB. Combining multiple clinical datasets and previous studies on Mtb and miRNAs, we state that pathogens can exploit interactions between miRNAs and other biomolecules to avoid host mechanisms of immune-mediated clearance and survive in host cells for a long time. During the interaction between Mtb and host cells, miRNA expression levels are altered, resulting in the changes in the miRNA-mediated regulation of host cell metabolism, inflammatory responses, apoptosis, and autophagy. In addition, differential miRNA expression can be used to distinguish healthy individuals, patients with TB, and patients with latent TB. This review summarizes the roles of miRNAs in immune regulation and their application as biomarkers in TB. These findings could provide new opportunities for the diagnosis and treatment of TB.

The pivotal role of miRNA-21 in myocardial metabolic flexibility in response to short- and long-term high glucose treatment: Evidence in human cardiomyocyte cell line

AIM

miRNA-21 is a crucial regulator of developing cardiac diseases, but its role is still controversial, and therefore it is necessary to clarify, at cardiac level, its involvement in high glucose induced-acute and chronic cardiac damage.

METHODS

Human ventricular cardiac myoblasts AC16, treated and not with miRNA-21 inhibitor, were exposed to high glucose for 2 and 7 days, and the expression of damage markers were investigated. Further, cardiac energetic metabolism was evaluated by measuring both the expression of glucose transporters and lipids regulators.

RESULTS

Short-term high glucose treatment induced a significant increase in miRNA-21 expression (p < 0.05) that was associated with an increase in hydrogen ion flux and energy potential dissipation without any change in energy production or increase in genes expression involved in cellular damage. miRNA-21 reduction observed (p < 0.05) at 7 days of high glucose treatment, induced the activation of damage pathways and compromised mitochondrial function (p < 0.05).

CONCLUSION

In human cardiomyocytes, the abundance of miRNA-21 takes part in first defense mechanism against cardiac insult and its cardioprotective effect depends on time of exposure to injury. Moreover, miRNA-21 regulates mitochondrial respiration and the ability of cells to select the most appropriate substrate for ATP production in given environment.

Long non-coding RNA MEG3 promotes tumor necrosis factor-alpha induced oxidative stress and apoptosis in interstitial cells of cajal via targeting the microRNA-21 /I-kappa-B-kinase beta axis

Interstitial Cells of Cajal (ICC) plays a critical role in the peristaltic contractions of the gastrointestinal and urinary tract. The dysfunction and loss of ICC contributes to hypokinetic disease, such as gallstoneand ureteropelvic junction obstruction . In the present study, we identified the underlying driving molecular signals of oxidative stress and apoptosis in ICC. ICC was isolated from small intestine of Balb/c mice, and stimulated with tumor necrosis factor-alpha (TNF-α). MTT and flow cytometry were performed to assess cell viability, apoptosis, and the level of reactive oxygen species in ICC, respectively. The level of malondialdehyde, superoxide dismutase, and glutathione peroxidase in cells were measured to assess oxidative stress. The expression of inflammatory factors (interleukin, IL-1 and IL-6) and apoptosis-related proteins were detected by western blot. We observed that TNF-αinduced inflammation, oxidative stress and cell apoptosis in ICC. By using quantitative real-time PCR , we verified that the expression of long non-coding RNAMEG3 was elevated by TNF-α in ICC. Silencing MEG3 reversed inflammation, oxidative stress, and cell apoptosisin TNF-α-treated ICC. Subsequently, we confirmed that MEG3 sponged cytoprotective miR-21 to upregulate the expression of I-kappa-B-kinase beta (IKKB) and activate the nuclear factor kappa-B (NF-κB) pathway. Both miR-21 overexpression and IKKB knockdown reduced TNF-α-induced above symptoms in ICC. Taken together, we can conclude that MEG3 mediates inflammation, oxidative stress and apoptosis in TNF-α-treated ICC via the miR-21/IKKB-NF-κB axis. The study improves our understanding of the molecular mechanism of ICC reduction related diseases.

Exosome-Mediated miR-21 Was Involved in the Promotion of Structural and Functional Recovery Effect Produced by Electroacupuncture in Sciatic Nerve Injury

PURPOSE

Our study is aimed at investigating the mechanism by which electroacupuncture (EA) promoted nerve regeneration by regulating the release of exosomes and exosome-mediated miRNA-21 (miR-21) transmission. Furthermore, the effects of Schwann cells- (SC-) derived exosomes on the overexpression of miR-21 for the treatment of PNI were investigated.

METHODS

A sciatic nerve injury model of rat was constructed, and the expression of miR-21 in serum exosomes and damaged local nerves was detected using RT-qPCR after EA treatment. The exosomes were identified under a transmission electron microscope and using western blotting analysis. Then, the exosome release inhibitor, GW4869, and the miR-21-5p-sponge used for the knockdown of miR-21 were used to clarify the effects of exosomal miR-21 on nerve regeneration promoted by EA. The nerve conduction velocity recovery rate, sciatic nerve function index, and wet weight ratio of gastrocnemius muscle were determined to evaluate sciatic nerve function recovery. SC proliferation and the level of neurotrophic factors were assessed using immunofluorescence staining, and the expression levels of SPRY2 and miR-21 were detected using RT-qPCR analysis. Subsequently, the transmission of exosomal miR-21 from SC to the axon was verified in vitro. Finally, the exosomes derived from the SC infected with the miR-21 overexpression lentivirus were collected and used to treat the rat SNI model to explore the therapeutic role of SC-derived exosomes overexpressing miR-21.

RESULTS

We found that EA inhibited the release of serum exosomal miR-21 in a PNI model of rats during the early stage of PNI, while it promoted its release during later stages. EA enhanced the accumulation of miR-21 in the injured nerve and effectively promoted the recovery of nerve function after PNI. The treatment effect of EA was attenuated when the release of circulating exosomes was inhibited or when miR-21 was downregulated in local injury tissue via the miR-21-5p-sponge. Normal exosomes secreted by SC exhibited the ability to promote the recovery of nerve function, while the overexpression of miR-21 enhanced the effects of the exosomes. In addition, exosomal miR-21 secreted by SC could promote neurite outgrowth in vitro.

CONCLUSION

Our results demonstrated the mechanism of EA on PNI from the perspective of exosome-mediated miR-21 transport and provided a theoretical basis for the use of exosomal miR-21 as a novel strategy for the treatment of PNI.

Silencing circular RNAPTPN12 promoted the growth of keloid fibroblasts by activating Wnt signaling pathway via targeting microRNA-21-5p

Keloid is a skin disease marked by fibroplasia, and fibroblasts viability plays a considerable part in keloid. Our research was devoted to assessing the involvement and mechanism of circPTPN12 in keloid. The level of circPTPN12 and miR-21-5p was estimated by qRT-PCR in keloid tissues and cells. MTT analysis was devoted to evaluating the multiplication of keloid fibroblasts. Additionally, transwell assay was dedicated to verifying cell migration and invasion. Furthermore, keloid fibroblasts apoptosis level was assessed adopting flow cytometry, and the relevancy between miR-21-5p and circPTPN12, miR-21-5p, and SMAD7 was assessed by dual luciferase assay. Similarly, RIP and RNA pull-down assay verified the relevance between genes. Moreover, levels of SMAD7 and proteins concerned in Wnt signaling pathway were appraised by Western blot. The level of circPTPN12 declined in keloid. circPTPN12 knockout could enhance the multiplication, migration, invasion, and decline apoptosis of keloid fibroblasts. Indeed, miR-21-5p could be packed with circPTPN12 sponge, SMAD7 was downstream effect factor of miR-21-5p, and miR-21-5p inhibitors partially reversed the promoting effect of silencing circPTPN12 on keloid formation. Otherwise, the level of SMAD7 was adjusted by circPTPN12 and miR-21-5p. Silencing circPTPN12 targeted miR-21-5p and activated Wnt pathway to accelerate keloid fibroblasts growth. Taken together, silencing circPTPN12 promotes the growth of keloid fibroblasts by activating Wnt pathway targeting miR-21-5p. CircPTPN12 may play a considerable part in keloid formation, which supplies a reference for molecularly targeted therapy keloid.

MicroRNAs as Factors in Bidirectional Crosstalk Between Mitochondria and the Nucleus During Cellular Senescence

Mitochondria are essential organelles that generate most of the chemical energy to power the cell through ATP production, thus regulating cell homeostasis. Although mitochondria have their own independent genome, most of the mitochondrial proteins are encoded by nuclear genes. An extensive bidirectional communication network between mitochondria and the nucleus has been discovered, thus making them semi-autonomous organelles. The nucleus-to-mitochondria signaling pathway, called Anterograde Signaling Pathway can be deduced, since the majority of mitochondrial proteins are encoded in the nucleus, less is known about the opposite pathway, the so-called mitochondria-to-nucleus retrograde signaling pathway. Several studies have demonstrated that non-coding RNAs are essential "messengers" of this communication between the nucleus and the mitochondria and that they might have a central role in the coordination of important mitochondrial biological processes. In particular, the finding of numerous miRNAs in mitochondria, also known as mitomiRs, enabled insights into their role in mitochondrial gene transcription. MitomiRs could act as important mediators of this complex crosstalk between the nucleus and the mitochondria. Mitochondrial homeostasis is critical for the physiological processes of the cell. Disruption at any stage in their metabolism, dynamics and bioenergetics could lead to the production of considerable amounts of reactive oxygen species and increased mitochondrial permeability, which are among the hallmarks of cellular senescence. Extensive changes in mitomiR expression and distribution have been demonstrated in senescent cells, those could possibly lead to an alteration in mitochondrial homeostasis. Here, we discuss the emerging putative roles of mitomiRs in the bidirectional communication pathways between mitochondria and the nucleus, with a focus on the senescence-associated mitomiRs.

Clinical Significance of Color Ultrasound, MRI, miR-21, and CA199 in the Diagnosis of Pancreatic Cancer

Background

To investigate the clinical significance of color ultrasound, magnetic resonance imaging (MRI), miR-21, and CA199 in the diagnosis of pancreatic cancer (PC).

Methods

A total of 160 patients with PC admitted to our hospital from April 2018 to February 2021 were included in the PC group, and another 100 patients with benign pancreatic disease during the same period were included in the pancreatic benign disease group. Color ultrasound and MRI were used for imaging examination of the two groups of PC patients, and the sensitivity, accuracy, and specificity of the two methods for preoperative diagnosis of PC were calculated, respectively. A total of 100 healthy people who underwent physical examination during the same period were included in the control group. Serum CA199 levels of the three groups were detected by ELISA assay. The level of serum miR-21 in the three groups was detected by qRT-PCR. A receiver operating curve (ROC) was drawn to analyze and calculate the sensitivity, specificity, and accuracy of the two serum markers and the combination of color ultrasound and MRI in the detection of PC.

Results

Serum CA199 and miR-21 levels in the PC group were significantly higher than those in the benign lesion group and control group. CA199 and miR-21 levels in the benign lesion group were higher than those in the control group. Both color ultrasound and MRI showed a higher detection rate for PC, and the sensitivity and accuracy were significantly higher than those of CA199 and miR-21. The sensitivity, specificity, and accuracy of combined detection were 91.88%, 96.00%, and 93.46%, respectively, which were significantly higher than those of single detection.

Conclusion

The combined detection of color ultrasound, MRI, miR-21, and CA199 have a high application value in the early diagnosis of PC, which can effectively improve the sensitivity and accuracy of clinical diagnosis, reduce the probability of missed diagnosis and misdiagnosis, and provide a reference for the rational clinical treatment plan and prognosis.

Value of circulating miRNA-21 in the diagnosis of subclinical diabetic cardiomyopathy

BACKGROUND

Diabetic cardiomyopathy (DCM) is a type of cardiac dysfunction that affects approximately 12% of diabetic patients, ultimately leading to heart failure or even death. However, there is currently no efficient or specific biomarker for DCM diagnosis.

METHODS

A total of 266 subjects with type II diabetes (T2DM) were enrolled in this study and were divided into the T2DM with cardiac dysfunction (DCM) group and T2DM without cardiac dysfunction (non-DCM) group. The diagnostic efficacy of miR-21 was determined and compared with that of serum hemoglobin A1c% (HbA1c%). Db/db mice and H9c2 cells stimulated with high glucose (HG)/high fatty acid (PA) were used as in vivo and in vitro models of DCM, respectively.

RESULTS

Through echocardiography and gated-myocardial perfusion imaging (gated-MPI), 49 patients were selected to be enrolled in the DCM group, with 49 matched controls in the non-DCM group. The circulating miR-21 levels were significantly decreased in the DCM group compared to the non-DCM group (P < 0.001). The diagnostic efficiency of miR-21 (area under the curve AUC = 0.899) was higher than that of other parameters, including HbA1c%. Moreover, when miR-21 was combined with the duration of diabetes, HbA1c%, and lipid profiles, the AUC was the highest (AUC = 0.939) and had the highest diagnostic efficiency. Furthermore, overexpression of miR-21 improved the impaired mitochondrial biogenesis and decreased the cardiomyocyte apoptosis induced by HG/PA, while inhibition of miR-21 exerted the opposite effects.

CONCLUSIONS

Our findings identify circulating miR-21 as a novel biomarker in the diagnosis of DCM and provide an underlying mechanism for miRNA-based therapy for the treatment of DCM.

TRIAL REGISTRATION

The study was approved by the Ethics Committee of the Third Affiliated Hospital of Soochow University and has been registered in the Chinese Clinical Trial Registry (ChiCTR1900027080).

A journey into the world of insect lipid metabolism

Lipid metabolism is fundamental to life. In insects, it is critical, during reproduction, flight, starvation, and diapause. The coordination center for insect lipid metabolism is the fat body, which is analogous to the vertebrate adipose tissue and liver. Fat body contains various different cell types; however, adipocytes and oenocytes are the primary cells related to lipid metabolism. Lipid metabolism starts with the hydrolysis of dietary lipids, absorption of lipid monomers, followed by lipid transport from midgut to the fat body, lipogenesis or lipolysis in the fat body, and lipid transport from fat body to other sites demanding energy. Lipid metabolism is under the control of hormones, transcription factors, secondary messengers and posttranscriptional modifications. Primarily, lipogenesis is under the control of insulin-like peptides that activate lipogenic transcription factors, such as sterol regulatory element-binding proteins, whereas lipolysis is coordinated by the adipokinetic hormone that activates lipolytic transcription factors, such as forkhead box class O and cAMP-response element-binding protein. Calcium is the primary-secondary messenger affecting lipid metabolism and has different outcomes depending on the site of lipogenesis or lipolysis. Phosphorylation is central to lipid metabolism and multiple phosphorylases are involved in lipid accumulation or hydrolysis. Although most of the knowledge of insect lipid metabolism comes from the studies on the model Drosophila; other insects, in particular those with obligatory or facultative diapause, also have great potential to study lipid metabolism. The use of these models would significantly improve our knowledge of insect lipid metabolism.

Mitochondrial noncoding RNA-regulatory network in cardiovascular disease

Mitochondrial function and integrity are vital for the maintenance of cellular homeostasis, particularly in high-energy demanding cells. Cardiomyocytes have a large number of mitochondria, which provide a continuous and bulk supply of the ATP necessary for cardiac mechanical function. More than 90% of the ATP consumed by the heart is derived from the mitochondrial oxidative metabolism. Decreased energy supply as the main consequence of mitochondrial dysfunction is closely linked to cardiovascular disease (CVD). The discovery of noncoding RNA (ncRNAs) in the mitochondrial compartment has changed the traditional view of molecular pathways involved in the regulatory network of CVD. Mitochondrial ncRNAs participate in controlling cardiovascular pathogenesis by regulating glycolysis, mitochondrial energy status, and the expression of genes involved in mitochondrial metabolism. Understanding the underlying mechanisms of the association between impaired mitochondrial function resulting from fluctuation in expression levels of ncRNAs and specific disease phenotype can aid in preventing and treating CVD. This review presents an overview of the role of mitochondrial ncRNAs in the complex regulatory network of the cardiovascular pathology. We will summarize and discuss (1) mitochondrial microRNAs (mitomiRs) and long noncoding RNAs (lncRNAs) encoded either by nuclear or mitochondrial genome which are involved in the regulation of mitochondrial metabolism; (2) the role of mitomiRs and lncRNAs in the pathogenesis of several CVD such as hypertension, cardiac hypertrophy, acute myocardial infarction and heart failure; (3) the biomarker and therapeutic potential of mitochondrial ncRNAs in CVD; (4) and the challenges inherent to their translation into clinical application.

Plin5 deficiency exacerbates pressure overload-induced cardiac hypertrophy and heart failure by enhancing myocardial fatty acid oxidation and oxidative stress

While cardiac hypertrophy and heart failure are accompanied by significant alterations in energy metabolism, more than 50-70% of energy is obtained from fatty acid β-oxidation (FAO) in adult hearts under physiological conditions. Plin5 is involved in the metabolism of lipid droplets (LDs) and is highly abundant in oxidative tissues including heart, liver and skeletal muscle. Plin5 protects the storage of triglyceride (TG) in LDs by inhibiting lipolysis, thereby suppressing excess FAO and preventing excessive oxidative stress in the heart. In this study, we investigated the roles of Plin5 in cardiac hypertrophy and heart failure in mice treated with transverse aortic constriction (TAC). The results indicated that Plin5 deficiency aggravated myocardial hypertrophy in the TAC-treated mice and exacerbated the TAC-induced heart failure. We also found that Plin5 deficiency reduced the cardiac lipid accumulation and upregulated the levels of PPARα and PGC-1α, which stimulate mitochondrial proliferation. Moreover, Plin5 deficiency aggravated the TAC-induced oxidative stress. We consistently found that Plin5 knockdown disrupted TG storage and elevated FAO and lipolysis in H9C2 rat cardiomyocytes. In addition, Plin5 knockdown also provoked mitochondrial proliferation and lipotoxic injury in H9C2 cells. In conclusion, Plin5 deficiency increases myocardial lipolysis, elevates FAO and oxidative burden, and thereby exacerbates cardiac hypertrophy and heart failure in TAC-treated mice.

Redox signaling in aging kidney and opportunity for therapeutic intervention through natural products

Kidney diseases are serious public problems with high morbidity and mortality in the general population and heavily retard renal function with aging regardless of the cause. Although myriad strategies have been assigned to prevent or harness disease progression, unfortunately, thus far, there is a paucity of effective therapies partly due to an insufficient knowledge of underlying pathological mechanisms, indicating deeper studies are urgently needed. Additionally, natural products are increasingly recognized as an alternative source for disease intervention owing to the potent safety and efficacy, which might be exploited for novel drug discovery. In this review, we primarily expatiate the new advances on mediators that might be amenable to targeting aging kidney and kidney diseases, including nicotinamide adenine dinucleotide phosphate oxidase (NOX), transforming growth factor-β (TGF-β), renin-angiotensin system (RAS), nuclear factor-erythroid 2 related factor 2 (Nrf2), peroxisome proliferator-activated γ receptor (PPARγ), advanced glycation endproducts (AGEs) as well as microRNAs and vitagenes. Of note, we conclude by highlighting some natural products which have the potential to facilitate the development of novel treatment for patients with myriad renal diseases.

miR-146b-5p has a sex-specific role in renal and cardiac pathology in a rat model of chronic kidney disease

Chronic kidney disease presents a complex and distinct pathological landscape in men and women, yet this difference is poorly understood. microRNAs are powerful molecular regulators of pathophysiology in the kidney and other organs. We previously reported a significant upregulation of miR-146b-5p in the 5/6 nephrectomy rat model of chronic kidney disease. Here we investigated the sex-specific contribution of miR-146b-5p to renocardiac pathology by generating a novel miR-146b^-/- rat and characterized the expression of miR-146b-5p in both wild-type and knockout animals. The 5/6 nephrectomy or sham surgery was performed on rats of each genotype and sex. Renal pathology was examined through gross histology, plasma and urinary analysis of electrolytes and metabolites, and by chronic blood pressure monitoring. Cardiac pathology was monitored via echocardiography and pressure-volume analysis. The miR-146b^-/- rats show functional knockout of miR-146b-5p in both the kidney and heart. While 5/6 nephrectomy induced tissue hypertrophy, miR-146b^-/- female rats displayed exacerbated renal hypertrophy. Additionally, miR-146b^-/- female rats exhibited a marked elevation of renal fibrosis and significant renal dysfunction yet lower blood pressure and less pronounced cardiac remodeling. These phenotypic differences were not exhibited in miR-146b^-/- male rats. Ovariectomy ameliorated renal pathology and abolished genotypic differences. In vitro examination of transforming growth factor-β signaling in combination with miR-146b-5p manipulation supports a role for miR-146b-5p in mediating the protective benefit of estrogen from renal pathologies. Thus, our data highlight an important role of miR-146b-5p in modulating kidney disease progression and provide new avenues for the study of sex-specific pathology.