H19 lncRNA Promotes Skeletal Muscle Insulin Sensitivity in Part by Targeting AMPK

Effects of corn completely replacement by broken rice, wheat, and rice bran and enzyme preparation supplementation on growth performance, meat quality, digestive function, and glucose metabolism of Langshan chickens

BACKGROUND

The aim of this experiment was to evaluate the effects of a completely alternative to corn diet, addition of compound enzymes or their combination on growth performance, intestinal digestive enzyme activity, nutrient apparent digestibility and gene expression related to energy metabolism in the breast muscle of Langshan chickens. In total, 192 30-day-old birds were used in a 2 × 2 factorial design, with respect to the main effects of diets (corn or alternative) and enzymes (absent or present). The experimental period was two phases of 28 days each.

RESULTS

An interaction was observed between diet and enzyme for average daily feed intake (ADFI). Compared to corn-soybean meal basal diet, although the alternative diet showed a decrease (P < 0.05) on ADFI, the alternative diet with compound enzymes showed an improvement (P < 0.05). The main effect of alternative diets improved (P < 0.05) the digestibility of gross energy (GE). The metabolism related gene expression of SGLT-1 and GLUT-2 was significantly up-regulated (P < 0.05). Furthermore, the compound enzymes improved (P < 0.05) dry matter (DM), crude protein (CP) and GE apparent digestibility. Enzyme supplementation elevated (P < 0.05) jejunal chyme amylase, mucosal maltase, and sucrase activity. It also enhanced (P < 0.05) serum albumin (ALB), triiodothyronine (T3), glucose and insulin levels.

CONCLUSION

The completely alternative diet, compound enzymes supplementation or their combination, had no negative impact on nutrient digestion, and had a beneficial effect on the growth performance of Langshan chickens. The combination of the diet and enzyme played a synergistic effect in improving growth performance. © 2025 Society of Chemical Industry.

XLOC_015548 Mitigates Skeletal Muscle Atrophy via the Gadd45g/MEK/ERK Pathway and Redox Regulation

BACKGROUND

Skeletal muscle atrophy is a common musculoskeletal disorder that significantly reduces patient quality of life. Long non-coding RNA (lncRNA) XLOC_015548 has been identified as a pivotal regulator of C2C12 myoblast proliferation and differentiation. However, its role in mitigating denervation-induced muscle atrophy and the underlying mechanisms remain unclear.

METHODS

We employed lentiviral-mediated stable expression of XLOC_015548 in C2C12 myoblasts and skeletal muscle-specific XLOC_015548-edited mouse models to investigate the function of this lncRNA. Muscle atrophy models were established in vitro by glucocorticoid-induced atrophy with dexamethasone (DEX) and in vivo by sciatic nerve transection-induced denervation. The MEK inhibitor U0126 was used to assess the role of the growth arrest and DNA damage-inducible 45 gamma/mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (Gadd45g/MEK/ERK) signaling pathway.

RESULTS

Overexpression of XLOC_015548 significantly activated the MEK/ERK signaling pathway (p < 0.05) by downregulating Gadd45g expression (p < 0.05) and promoting its cytoplasmic localization, thereby enhancing cell proliferation and myotube formation. Furthermore, XLOC_015548 reduced the level of reactive oxygen species (ROS) (p < 0.01), stabilized the mitochondrial membrane potential, and alleviated DEX-induced oxidative stress. These protective effects were partially reversed by U0126, confirming the involvement of the MEK/ERK pathway. Skeletal muscle-specific overexpression of XLOC_015548 in vivo significantly reduced denervation-induced muscle atrophy (q < 0.05) and increased the muscle fiber cross-sectional area.

CONCLUSION

XLOC_015548 plays a critical role in promoting myogenic differentiation and protecting against muscle atrophy by regulating Gadd45g expression, activating the MEK/ERK signaling pathway, and reducing oxidative stress. These findings underscore the therapeutic potential of XLOC_015548 in skeletal muscle atrophy, and provide a foundation for lncRNA-based treatment strategies.

Sexual Dimorphism in Cardiometabolic Diseases: From Development to Senescence and Therapeutic Approaches

The global incidence and prevalence of cardiometabolic disorders have risen significantly in recent years. Although lifestyle choices in adulthood play a crucial role in the development of these conditions, it is well established that events occurring early in life can have an important effect. Recent research on cardiometabolic diseases has highlighted the influence of sexual dimorphism on risk factors, underlying mechanisms, and response to therapies. In this narrative review, we summarize the current understanding of sexual dimorphism in cardiovascular and metabolic diseases in the general population and within the framework of the Developmental Origins of Health and Disease (DOHaD) concept. We explore key risk factors and mechanisms, including the influence of genetic and epigenetic factors, placental and embryonic development, maternal nutrition, sex hormones, energy metabolism, microbiota, oxidative stress, cell death, inflammation, endothelial dysfunction, circadian rhythm, and lifestyle factors. Finally, we discuss some of the main therapeutic approaches, responses to which may be influenced by sexual dimorphism, such as antihypertensive and cardiovascular treatments, oxidative stress management, nutrition, cell therapies, and hormone replacement therapy.

Role of exercise on the reduction of cancer development: a mechanistic review from the lncRNA point of view

More research has been done on the correlation between exercise and cancer, which has revealed several ways that physical activity decreases the risk of developing the disease. The developing function of lncRNAs as an important molecular link between exercise and cancer suppression is the main topic of this review. According to recent research, regular physical exercise also alters the expression levels of several lncRNAs, which are generally elevated in cancer. A complex network of interactions that may provide protective effects against carcinogenesis is suggested by the contribution of these lncRNAs in various cellular processes, such as epigenetic alterations, proliferation, and apoptosis regulation. We offer a comprehensive summary of the existing information regarding specific lncRNAs that are influenced by physical activity and could potentially impact cancer-related processes. We also go over the difficulties in interpreting these alterations, taking into account the fact that several lncRNAs have a dual function in promoting and preventing cancer in various physiological settings. To understand the complex impacts of exercise-induced lncRNA regulation in cancer biology, more study is required. The critique strongly highlights the possibility of lncRNAs serving as both indicators and treatment prospects for cancer-preventive strategies.

Stress-Related LncRNAs and Their Roles in Diabetes and Diabetic Complications

Diabetes mellitus (DM) is a chronic metabolic disorder and one of the most significant global health burdens worldwide. Key pathophysiological mechanisms underlying its onset and associated complications include hyperglycemia-related stresses, such as oxidative stress and endoplasmic reticulum stress (ER stress). Long non-coding RNAs (lncRNAs), defined as RNA transcripts longer than 200 nucleotides and lacking protein-coding capacity, play crucial roles in various biological processes and have emerged as crucial regulators in the pathogenesis of diabetes. This review provides a comprehensive overview of lncRNA biogenesis and its functional roles, emphasizing recent findings that link stress-related lncRNAs to diabetic pathology and complications. Also, we discuss how lncRNAs influence diabetes and its complications by modulating pathways involved in cell death, proliferation, inflammation, and fibrosis, which contribute to pancreatic β cell dysfunction, insulin resistance, diabetic nephropathy, and retinopathy. By analyzing current research, we aim to enhance understanding of lncRNA involvement in diabetes while identifying potential therapeutic targets and guiding future research directions to elucidate the complex mechanisms underlying this pervasive condition.

Positive feedback loop involving AMPK and CLYBL acetylation links metabolic rewiring and inflammatory responses

Metabolic rewiring underlies effective macrophages defense to respond disease microenvironment. However, the underlying mechanisms driving metabolic rewiring to enhance macrophage effector functions remain unclear. Here, we demonstrated that the metabolic reprogramming in inflammatory macrophages depended on the acetylation of CLYBL, a citramalyl-CoA lyase, at lysine 154 (K154), and blocking CLYBL-K154 acetylation restricted the release of pro-inflammatory factors. Mechanistically, we found a crucial AMPK-CLYBL acetylation positive feedback loop, triggered by toll-like receptors (TLRs), involving AMPK hypophosphorylation and CLYBL hyperacetylation. The deacetylase enzyme SIRT2 acted as the bridge between AMPK phosphorylation and CLYBL acetylation, thereby regulating macrophage polarization and the release of pro-inflammatory cytokines. Furthermore, CLYBL hypoacetylation decreased monocyte infiltration, thereby alleviating cardiac remodeling. These findings suggest that the AMPK-CLYBL acetylation positive feedback loop serves as a metabolic switch driving inflammatory response and inhibiting CLYBL-K154 acetylation may offer a promising therapeutic strategy for inflammatory response-related disorders.

Trimetazidine restores autophagy via lncRNA H19/AMPK in diabetic heart: Implications for its therapeutic value against diabetic cardiomyopathy

OBJECTIVE

Previous studies have shown that trimetazidine (TMZ) alleviates diabetes-induced cardiac dysfunction. However, the underlying mechanism for its protective effects on cardiac function remains incompletely understood. Diminished autophagy was found in diabetic hearts, and restoration of autophagy generates cardioprotective effect. This study aims to investigate whether and how TMZ produces protective effect through increasing autophagic activity in the diabetic heart.

METHOD

A high-fat diet and low-dose streptozotocin were applied to induce type 2 diabetes mellitus (T2DM) in male C57BL/6 mice, followed by treatment with TMZ for 14 weeks before cardiac function was evaluated. To mimic the diabetic condition, the neonatal rat cardiomyocytes (NRCMs) were exposed to high glucose/palmitic acid (HP) in the presence or absence of TMZ.

RESULTS

We found that TMZ treatment promotes autophagic flux in cardiomyocytes, which is impaired in diabetes. We further found that the AMPK and lncRNA H19 played critical roles in mediating TMZ-induced enhancement of autophagy in cardiomyocyte. We showed that TMZ treatment restored the level of H19 and phosphorylated AMPK (p-AMPK T172) in diabetic heart and NRCMs exposed to HP. Of note, the effect of TMZ on autophagy and p-AMPK was abolished by knockdown of H19.

CONCLUSION

These findings indicated that TMZ is able to recover the cardiac autophagic activity which is impaired by T2DM, and the underlying mechanism accounted for this ability is mostly likely attributed to the restored expression of H19 and AMPK activity.

Inflammatory markers and noncoding-RNAs responses to low and high compressions of HIIT with or without berberine supplementation in middle-aged men with prediabetes

This study compared the capacity of two different models of HIIT [high-(HC) and low-(LC) compression], with or without the use of berberine (BBR), on NOD-like receptor pyrin domain-containing protein-3 (NLRP3), H19, interleukin (IL)-1β, high-sensitivity C-reactive protein (hs-CRP), and insulin resistance markers. Fifty-four middle-aged men with overweight or obesity and prediabetes [fasting blood glucose (FBG) 110-180 mg/dL] were randomly and equally assigned to the HC, LC, HC + BBR, LC + BBR, BBR, and non-exercising control (CON) groups. The HC (2:1 work-to-rest) and LC (1:1 work-to-rest) home-based training programs included 2-4 sets of 8 exercises at 80%-95% HRmax, twice a week for 8 weeks. Participants in the berberine groups received approximately 1000 mg daily. All exercise interventions led to a significant reduction in hs-CRP, IL-1β, insulin, FBG, and insulin resistance index (HOMA-IR) versus CON. Notably, there was a significant reduction in FBG and HOMA-IR with the BBR group compared to the baseline. Both NLRP3 and H19 experienced a significant drop only with LC in comparison to the baseline. While both exercise protocols were beneficial overall, LC uniquely exhibited more anti-inflammatory effects, as indicated by reductions in H19 and NLRP3. However, the addition of berberine to the exercise programs did not demonstrate additional benefits.

Long Noncoding RNAs in Diet-Induced Metabolic Diseases

The prevalence of metabolic diseases, including type 2 diabetes and metabolic dysfunction-associated steatotic liver disease (MASLD), is steadily increasing. Although many risk factors, such as obesity, insulin resistance, or hyperlipidemia, as well as several metabolic gene programs that contribute to the development of metabolic diseases are known, the underlying molecular mechanisms of these processes are still not fully understood. In recent years, it has become evident that not only protein-coding genes, but also noncoding genes, including a class of noncoding transcripts referred to as long noncoding RNAs (lncRNAs), play key roles in diet-induced metabolic disorders. Here, we provide an overview of selected lncRNA genes whose direct involvement in the development of diet-induced metabolic dysfunctions has been experimentally demonstrated in suitable in vivo mouse models. We further summarize and discuss the associated molecular modes of action for each lncRNA in the respective metabolic disease context. This overview provides examples of lncRNAs with well-established functions in diet-induced metabolic diseases, highlighting the need for appropriate in vivo models and rigorous molecular analyses to assign clear biological functions to lncRNAs.

Restoration of epigenetic impairment in the skeletal muscle and chronic inflammation resolution as a therapeutic approach in sarcopenia

Sarcopenia is an age-associated loss of skeletal muscle mass, strength, and function, accompanied by severe adverse health outcomes, such as falls and fractures, functional decline, high health costs, and mortality. Hence, its prevention and treatment have become increasingly urgent. However, despite the wide prevalence and extensive research on sarcopenia, no FDA-approved disease-modifying drugs exist. This is probably due to a poor understanding of the mechanisms underlying its pathophysiology. Recent evidence demonstrate that sarcopenia development is characterized by two key elements: (i) epigenetic dysregulation of multiple molecular pathways associated with sarcopenia pathogenesis, such as protein remodeling, insulin resistance, mitochondria impairments, and (ii) the creation of a systemic, chronic, low-grade inflammation (SCLGI). In this review, we focus on the epigenetic regulators that have been implicated in skeletal muscle deterioration, their individual roles, and possible crosstalk. We also discuss epidrugs, which are the pharmaceuticals with the potential to restore the epigenetic mechanisms deregulated in sarcopenia. In addition, we discuss the mechanisms underlying failed SCLGI resolution in sarcopenia and the potential application of pro-resolving molecules, comprising specialized pro-resolving mediators (SPMs) and their stable mimetics and receptor agonists. These compounds, as well as epidrugs, reveal beneficial effects in preclinical studies related to sarcopenia. Based on these encouraging observations, we propose the combination of epidrugs with SCLI-resolving agents as a new therapeutic approach for sarcopenia that can effectively attenuate of its manifestations.

Transcriptome Data Revealed the circRNA-miRNA-mRNA Regulatory Network during the Proliferation and Differentiation of Myoblasts in Shitou Goose

CircRNA, a recently characterized non-coding RNA (ncRNA) variant, functions as a molecular sponge, exerting regulatory control by binding to microRNA (miRNA) and modulating the expression of downstream proteins, either promoting or inhibiting their expression. Among poultry species, geese hold significant importance, prized by consumers for their delectable taste and rich nutritional content. Despite the prominence of geese, research on the growth and development of goose muscle, particularly the regulatory role of circRNAs in goose muscle formation, remains insufficiently explored. In this study, we constructed comprehensive expression profiles of circRNAs and messenger RNAs (mRNAs) within the myoblasts and myotubes of Shitou geese. We identified a total of 96 differentially expressed circRNAs (DEcircRNAs) and 880 differentially expressed mRNAs (DEmRNAs). Notably, the parental genes of DEcircRNAs and DEmRNAs exhibited enrichment in the Wnt signaling pathway, highlighting its potential impact on the proliferation and differentiation of goose myoblasts. Employing RNAhybrid and miRDB, we identified circRNA-miRNA pairs and mRNA-miRNA pairs that may play a role in regulating myogenic differentiation or muscle growth. Subsequently, utilizing Cytoscape, we constructed a circRNA-miRNA-mRNA interaction network aimed at unraveling the intricate regulatory mechanisms involved in goose muscle growth and development, which comprises 93 circRNAs, 351 miRNAs, and 305 mRNAs. Moreover, the identification of 10 hub genes (ACTB, ACTN1, BDNF, PDGFRA, MYL1, EFNA5, MYSM1, THBS1, ITGA8, and ELN) potentially linked to myogenesis, along with the exploration of their circRNA-miRNA-hub gene regulatory axis, was also conducted. These competitive endogenous RNA (ceRNA) regulatory networks elucidate the molecular regulatory mechanisms associated with muscle growth in Shitou geese, providing deeper insights into the reciprocal regulation of circRNA, miRNA, and mRNA in the context of goose muscle formation.

LncRNA H19 inhibition impairs endoplasmic reticulum-mitochondria contact in hepatic cells and augments gluconeogenesis by increasing VDAC1 levels

Inspite of exerting independent cellular functions, the endoplasmic-reticulum (ER) and the mitochondria also physically connect at specific sites termed mitochondria-associated ER membranes (MAMs) and these sites consist of several tethering proteins that play varied roles in diverse cellular processes. However, the regulation of these tethering proteins within the cell is relatively less studied. Here, we show that several MAM proteins are significantly altered in the liver during diabetes and among these, the lncRNA, H19 regulates the levels of VDAC1. Inhibition of H19 expression using H19 specific siRNA altered VDAC1, mitochondrial Ca2+ and oxygen consumption rate, ATP and ROS levels and enhanced ER and mitochondria coupling in Hepa 1-6 cells. While H19 inhibition did not impact lipid accumulation, levels of gluconeogenic genes were significantly increased. JNK-phosphorylation and IRS1-Ser307-phosphorylation were increased by H19 inhibition and this was associated with abrogation of insulin-stimulated AKT (Ser-473) phosphorylation and glucose uptake in Hepa 1-6 cells. While inhibition of VDAC1 expression using siRNAs and with metformin significantly rescued the effects of H19 inhibition, VDAC1 overexpression alone exerted effects similar to H19 inhibition, suggesting that VDAC1 increase mediates the adverse effects of H19. In-vivo H19 inhibition using specific siRNAs increased hepatic VDAC1, pJNK and pIRS1 (Ser307) levels and decreased AKT (Ser-473) phosphorylation in mice. These suggest an important role of the H19-VDAC1 axis in ER-mitochondria coupling and regulation of gluconeogenesis in the liver during diabetes.

Digeda-4 decoction and its disassembled prescriptions improve dyslipidemia and apoptosis by regulating AMPK/SIRT1 pathway on tyloxapol-induced nonalcoholic fatty liver disease in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Nonalcoholic fatty liver disease (NAFLD) is a manifestation of metabolic syndrome in the liver and the leading cause of chronic liver disease worldwide. Digeda-4 decoction (DGD-4) is a commonly prescribed Mongolian herbal drug for treating acute and chronic liver injury and fatty liver. However, the mechanisms underlying the improvement of dislipidemia and liver injury via treatment with DGD-4 remain unclear. Disassembling a prescription is an effective approach to studying the effects and mechanisms underlying Mongolian medicine prescriptions. By disassembling a prescription, it is feasible to discover effective combinations of individual herbs to optimize a given prescription. Accordingly, we disassembled DGD-4 into two groups: the single Lomatogonium rotatum (L.) Fries ex Nym (LR) (DGD-1) and non-LR (DGD-3).

AIM OF THIS STUDY

To study whether DGD-4 and its disassembled prescriptions have protective effects against tyloxapol (TY)-induced NAFLD and to explore the underlying mechanisms of action and compatibility of prescriptions.

MATERIAL AND METHODS

NAFLD mice were developed by TY induction. Biochemical horizontal analyses, enzyme-linked immunosorbent assay, and liver histological staining were performed to explore the protective effects of DGD-4 and its disassembled prescriptions DGD-3 and DGD-1. Furthermore, we performed immunohistochemical analyses and Western blotting to further explore the expression of target proteins.

RESULTS

DGD-4 and its disassembled prescriptions could inhibit TY-induced dislipidemia and liver injury. In addition, DGD-4 and its disassembled prescriptions increased the levels of p-AMPKα and p-ACC, but decreased the levels of SREBP1c, SCD-1, SREBP-2, and HMGCS1 proteins. The activation of lipid metabolic pathways SIRT1, PGC-1α, and PPARα improved lipid accumulation in the liver. Moreover, DGD-4 could inhibit hepatocyte apoptosis and treat TY-induced liver injury by upregulating the Bcl-2 expression, downregulating the expression of Bax, caspase-3, caspase-8, and the ratio of Bax/Bcl-2, and positively regulating the imbalance of oxidative stress (OxS) markers (such as superoxide dismutase [SOD], catalase [CAT], malondialdehyde [MDA], and myeloperoxidase [MPO]). DGD-1 was superior to DGD-3 in regulating lipid synthesis-related proteins such as SREBP1c, SCD-1, SREBP-2, and HMGCS1. DGD-3 significantly affected the expression of lipid metabolic proteins SIRT1, PGC-1α, PPARα, apoptotic proteins Bcl-2, Bax, caspase-3, caspase-8, and the regulation of Bax/Bcl-2 ratio. However, DGD-1 showed no regulatory effects on Bax and Bcl-2 proteins.

CONCLUSION

This study demonstrates the protective effects of DGD-4 in the TY-induced NAFLD mice through a mechanism involving improvement of dyslipidemia and apoptosis by regulating the AMPK/SIRT1 pathway. Although the Monarch drug DGD-1 reduces lipid accumulation and DGD-3 inhibits apoptosis and protects the liver from injury, DGD-4 can be more effective overall as a therapy when compared to DGD-1 and DGD-3.

Long noncoding RNA X-inactive specific transcript (lncRNA XIST) inhibits hepatic insulin resistance by competitively binding microRNA-182-5p

BACKGROUND

What is highlighted in this study refers to the role and molecular mechanism of long noncoding RNA (lncRNA) X-inactive specific transcript (XIST) in cells with insulin resistance (IR).

METHODS

In this study, LX-2 cells were applied to establish IR model in vitro. The expressions of lncRNA XIST, phosphoenolpyruvate carboxykinase (PEPCK,) and glucose-6-phosphatase (G6Pase) were quantified by quantitative reverse transcription polymerase chain reaction. The 2-deoxy-d-glucose-6-phosphate (2-DG6P) level was detected utilizing 2-deoxy-d-glucose (2-DG) uptake measurement kit. Western blot was adopted to measure the protein expressions of insulin-like growth factor-1 receptor (IGF-1R), G6Pase, PEPCK, and phosphatidylinositol 3-kinase (PI3K)/Akt pathway-related genes. StarBase was used to predict the targeting relationship between lncRNA XIST or IGF-1R with miR-182-5p, the results of which were verified by dual-luciferase reporter, RNA pull-down, and RNA immunoprecipitation assays. Rescue experiments were conducted to investigate the effect of miR-182-5p on IR cells. Next, low-expressed lncRNA XIST and high-expressed miR-182-5p were observed in IR cells.

RESULTS

Upregulation of lncRNA XIST increased IGF-1R and 2-DG6P levels, decreased G6Pase and PEPCK expressions, and promoted PI3K/Akt pathway activation in IR cells. LncRNA XIST sponged miR-182-5p which targeted IGF-1R. MiR-182-5p mimic reversed the above effects of lncRNA XIST overexpression on IR cells.

CONCLUSIONS

In conclusion, lncRNA XIST/miR-182-5p axis alleviates hepatic IR in vitro via IGF-1R/PI3K/Akt signaling pathway, which could be the promising therapeutic target.

Exercise ameliorates skeletal muscle insulin resistance by modulating GRK4-mediated D1R expression

Exercise has been recommended as a nonpharmaceutical therapy to treat insulin resistance (IR). Previous studies showed that dopamine D1-like receptor agonists, such as fenoldopam, could improve peripheral insulin sensitivity, while antipsychotics, which are dopamine receptor antagonists, increased susceptibility to Type 2 diabetes mellitus (T2DM). Meanwhile, exercise has been proved to stimulate dopamine receptors. However, whether the dopamine D1 receptor (D1R) is involved in exercise-mediated amelioration of IR remains unclear. We found that the D1-like receptor antagonist, SCH23390, reduced the effect of exercise on lowering blood glucose and insulin in insulin-resistant mice and inhibited the contraction-induced glucose uptake in C2C12 myotubes. Similarly, the opposite was true for the D1-like receptor agonist, fenoldopam. Furthermore, the expression of D1R was decreased in skeletal muscles from streptozotocin (STZ)- and high-fat intake-induced T2DM mice, accompanied by increased D1R phosphorylation, which was reversed by exercise. A screening study showed that G protein-coupled receptor kinase 4 (GRK4) may be the candidate kinase for the regulation of D1R function, because, in addition to the increased GRK4 expression in skeletal muscles of T2DM mice, GRK4 transgenic T2DM mice exhibited lower insulin sensitivity, accompanied by higher D1R phosphorylation than control mice, whereas the AAV9-shGRK4 mice were much more sensitive to insulin than AAV9-null mice. Mechanistically, the up-regulation of GRK4 expression caused by increased reactive oxygen species (ROS) in IR was ascribed to the enhanced expression of c-Myc, a transcriptional factor of GRK4. Taken together, the present study shows that exercise, via regulation of ROS/c-Myc/GRK4 pathway, ameliorates D1R dysfunction and improves insulin sensitivity.

Long noncoding RNA (lncRNA) H19: An essential developmental regulator with expanding roles in cancer, stem cell differentiation, and metabolic diseases

Recent advances in deep sequencing technologies have revealed that, while less than 2% of the human genome is transcribed into mRNA for protein synthesis, over 80% of the genome is transcribed, leading to the production of large amounts of noncoding RNAs (ncRNAs). It has been shown that ncRNAs, especially long non-coding RNAs (lncRNAs), may play crucial regulatory roles in gene expression. As one of the first isolated and reported lncRNAs, H19 has gained much attention due to its essential roles in regulating many physiological and/or pathological processes including embryogenesis, development, tumorigenesis, osteogenesis, and metabolism. Mechanistically, H19 mediates diverse regulatory functions by serving as competing endogenous RNAs (CeRNAs), Igf2/H19 imprinted tandem gene, modular scaffold, cooperating with H19 antisense, and acting directly with other mRNAs or lncRNAs. Here, we summarized the current understanding of H19 in embryogenesis and development, cancer development and progression, mesenchymal stem cell lineage-specific differentiation, and metabolic diseases. We discussed the potential regulatory mechanisms underlying H19's functions in those processes although more in-depth studies are warranted to delineate the exact molecular, cellular, epigenetic, and genomic regulatory mechanisms underlying the physiological and pathological roles of H19. Ultimately, these lines of investigation may lead to the development of novel therapeutics for human diseases by exploiting H19 functions.

Decreased expression of H19/miR-675 ameliorates muscle atrophy by regulating the IGF1R/Akt/FoxO signaling pathway

BACKGROUND

Long non-coding RNA (lncRNA) H19 is one of the most highly expressed and conserved transcripts in mammalian development, and its functions have been fully discussed in many contexts including tumorigenesis and skeletal muscle development. However, its exact role in muscle atrophy remains largely unknown. This study investigated the effect of lncRNA H19 on muscle atrophy and the potential underlying mechanism.

METHODS

Hindlimb suspension (HS) of C57BL/6 mice and starvation of C2C12 cells with PBS were conducted to induce atrophy. Real-time PCR and Western blotting were used to measure the expression of RNAs and proteins. LncRNA H19 and its encoded miR-675 were overexpressed or inhibited in different models of muscle atrophy. Immunofluorescence was carried out to examine the cross-sectional area (CSA) and minimal Feret's diameter (MFD) of myofibers and myotube diameter.

RESULTS

The expression levels of lncRNA H19 and miR-675 were significantly reduced in both the soleus and gastrocnemius muscles in response to HS. Overexpression of lncRNA H19 led to an increase in Atrogin-1 mRNA expression, and this effect was reversed by inhibiting miR-675. The overexpression of miR-675 aggravated both HS- and starving-induced muscle atrophy by inhibiting the IGF1R/Akt signaling pathway and promoting FoxO/Atrogin-1 expression. Conversely, miR-675 inhibition had the opposite effects.

CONCLUSION

The lncRNA H19/miR-675 axis can induce muscle atrophy, and its downregulation in mice with HS-induced muscle atrophy may act as a protective mechanism against this condition.

Genome-wide analysis of circular RNA-mediated ceRNA regulation in porcine skeletal muscle development

BACKGROUND

As a diverse and abundant class of endogenous RNAs, circular RNAs (circRNAs) participate in various biological processes including cell proliferation and apoptosis. Nevertheless, few researchers have investigated the role of circRNAs in muscle development in cultivated pigs.

RESULTS

In this study, we used RNA-seq to construct circRNA expression profiles in skeletal muscle of Jinfen White pigs at the age of 1, 90, and 180 days. Among the 16,990 identified circRNAs, 584 circRNAs were differentially expressed. Moreover, the enrichment analysis of DE circRNA host genes showed that they were mainly involved in muscle contraction, muscle organ development and muscle system processes, as well as AMPK and cAMP-related signal pathways. We also constructed a circRNA-miRNA-mRNA co-expression network to find key circRNAs which many involved in the regulation of porcine skeletal muscle development through the competitive endogenous RNA (ceRNA) mechanism. It is noteworthy that circ_0018595/miR-1343/PGM1 axis may play a regulatory role in the development of porcine skeletal muscle.

CONCLUSIONS

This study identified the circRNAs and present the circRNA expression profile in the development of pigs, revealed that DE circRNA host genes participate in different cell fates and enriched the porcine ceRNA network. Thus, this work will become a valuable resource for further in-depth study of the regulatory mechanism of circRNA in the development of porcine skeletal muscle.

Dietary Methionine Restriction Improves Gastrocnemius Muscle Glucose Metabolism through Improved Insulin Secretion and H19/IRS-1/Akt Pathway in Middle-Aged Mice

Methionine restriction (MR) improves glucose metabolism. In skeletal muscle, H19 is a key regulator of insulin sensitivity and glucose metabolism. Therefore, this study aims to reveal the underlying mechanism of H19 upon MR on glucose metabolism in skeletal muscle. Middle-aged mice were fed MR diet for 25 weeks. Mouse islets β cell line β-TC6 cells and mouse myoblast cell line C2C12 cells were used to establish the apoptosis or insulin resistance model. Our findings showed that MR increased B-cell lymphoma-2 (Bcl-2) expression, deceased Bcl-2 associated X protein (Bax), cleaved cysteinyl aspartate-specific proteinase-3 (Caspase-3) expression in pancreas, and promoted insulin secretion of β-TC6 cells. Meanwhile, MR increased H19 expression, insulin Receptor Substrate-1/insulin Receptor Substrate-2 (IRS-1/IRS-2) value, protein Kinase B (Akt) phosphorylation, glycogen synthase kinase-3β (GSK3β) phosphorylation, and hexokinase 2 (HK2) expression in gastrocnemius muscle and promoted glucose uptake in C2C12 cells. But these results were reversed after H19 knockdown in C2C12 cells. In conclusion, MR alleviates pancreatic apoptosis and promotes insulin secretion. And MR enhances gastrocnemius muscle insulin-dependent glucose uptake and utilization via the H19/IRS-1/Akt pathway, thereby ameliorating blood glucose disorders and insulin resistance in high-fat-diet (HFD) middle-aged mice.

Long Noncoding RNAs in the Pathogenesis of Insulin Resistance

Insulin resistance (IR), designated as the blunted response of insulin target tissues to physiological level of insulin, plays crucial roles in the development and progression of diabetes, nonalcoholic fatty liver disease (NAFLD) and other diseases. So far, the distinct mechanism(s) of IR still needs further exploration. Long non-coding RNA (lncRNA) is a class of non-protein coding RNA molecules with a length greater than 200 nucleotides. LncRNAs are widely involved in many biological processes including cell differentiation, proliferation, apoptosis and metabolism. More recently, there has been increasing evidence that lncRNAs participated in the pathogenesis of IR, and the dysregulated lncRNA profile played important roles in the pathogenesis of metabolic diseases including obesity, diabetes and NAFLD. For example, the lncRNAs MEG3, H19, MALAT1, GAS5, lncSHGL and several other lncRNAs have been shown to regulate insulin signaling and glucose/lipid metabolism in various tissues. In this review, we briefly introduced the general features of lncRNA and the methods for lncRNA research, and then summarized and discussed the recent advances on the roles and mechanisms of lncRNAs in IR, particularly focused on liver, skeletal muscle and adipose tissues.

Linc-RAM is a metabolic regulator maintaining whole-body energy homeostasis in mice

Long noncoding RNAs (lncRNAs) are known to have profound functions in regulating cell fate specification, cell differentiation, organogenesis, and disease, but their physiological roles in controlling cellular metabolism and whole-body metabolic homeostasis are less well understood. We previously identified a skeletal muscle-specific long intergenic noncoding RNA (linc-RNA) activator of myogenesis, Linc-RAM, which enhances muscle cell differentiation during development and regeneration. Here, we report that Linc-RAM exerts a physiological function in regulating skeletal muscle metabolism and the basal metabolic rate to maintain whole-body metabolic homeostasis. We first demonstrate that Linc-RAM is preferentially expressed in type-II enriched glycolytic myofibers, in which its level is more than 60-fold higher compared to that in differentiated myotubes. Consistently, genetic deletion of the Linc-RAM gene in mice increases the expression levels of genes encoding oxidative fiber versions of myosin heavy chains and decreases those of genes encoding rate-limiting enzymes for glycolytic metabolism. Physiologically, Linc-RAM-knockout mice exhibit a higher basal metabolic rate, elevated insulin sensitivity and reduced fat deposition compared to their wild-type littermates. Together, our findings indicate that Linc-RAM is a metabolic regulator of skeletal muscle metabolism and may represent a potential pharmaceutical target for preventing and/or treating metabolic diseases, including obesity.

Roles of long noncoding RNAs and small extracellular vesicle-long noncoding RNAs in type 2 diabetes

The prevalence of a high-energy diet and a sedentary lifestyle has increased the incidence of type 2 diabetes (T2D). T2D is a chronic disease characterized by high blood glucose levels and insulin resistance in peripheral tissues. The pathological mechanism of this disease is not fully clear. Accumulated evidence has shown that noncoding RNAs have an essential regulatory role in the progression of diabetes and its complications. The roles of small noncoding RNAs, such as miRNAs, in T2D, have been extensively investigated, while the function of long noncoding RNAs (lncRNAs) in T2D has been unstudied. It has been reported that lncRNAs in T2D play roles in the regulation of pancreatic function, peripheral glucose homeostasis and vascular inflammation. In addition, lncRNAs carried by small extracellular vesicles (sEV) were shown to mediate communication between organs and participate in diabetes progression. Some sEV lncRNAs derived from stem cells are being developed as potential therapeutic agents for diabetic complications. In this review, we summarize the current knowledge relating to lncRNA biogenesis, the mechanisms of lncRNA sorting into sEV and the regulatory roles of lncRNAs and sEV lncRNAs in diabetes. Knowledge of lncRNAs and sEV lncRNAs in diabetes will aid in the development of new therapeutic drugs for T2D in the future.

The regulation of LncRNA GTL2 expression by DNA methylation during sheep skeletal muscle development

DNA methylation has crucial roles in regulating the expression of genes involved in skeletal muscle development. However, the DNA methylation pattern of lncRNA during sheep skeletal muscle development remains unclear. This study investigated previous WGBS and LncRNA data in skeletal muscle of sheep (fetus and adult). We then focused on LncRNA GTL2, which is differentially expressed in skeletal muscle and has multiple DMRs. We found that the expression level of GTL2 decreased with age. GTL2 DMRs methylation levels were significantly higher in adult muscle than in fetal muscle. After 5AZA treatment, GTL2 expression was significantly increased in a dose-dependent manner.The dCas9-DNMT3A-sgRNA significantly reduced the expression level of GTL2 in cells, but increased GTL2 DMR methylation levels. The above studies indicate that dCas9-DNMT3A can effectively increase the methylation level in the DMR region of GTL2, the expression level of GTL2 is regulated by DNA methylation during muscle development.

Long Noncoding RNAs That Function in Nutrition: Lnc-ing Nutritional Cues to Metabolic Pathways

Long noncoding RNAs (lncRNAs) are sensitive to changing environments and play key roles in health and disease. Emerging evidence indicates that lncRNAs regulate gene expression to shape metabolic processes in response to changing nutritional cues. Here we review various lncRNAs sensitive to fasting, feeding, and high-fat diet in key metabolic tissues (liver, adipose, and muscle), highlighting regulatory mechanisms that trigger expression changes of lncRNAs themselves, and how these lncRNAs regulate gene expression of key metabolic genes in specific cell types or across tissues. Determining how lncRNAs respond to changes in nutrition is critical for our understanding of the complex downstream cascades following dietary changes and can shape how we treat metabolic disease. Furthermore, investigating sex biases that might influence lncRNA-regulated responses will likely reveal contributions toward the observed disparities between the sexes in metabolic diseases.

Signaling by LncRNAs: Structure, Cellular Homeostasis, and Disease Pathology

The cellular signaling network involves co-ordinated regulation of numerous signaling molecules that aid the maintenance of cellular as well as organismal homeostasis. Aberrant signaling plays a major role in the pathophysiology of many diseases. Recent studies have unraveled the superfamily of long non-coding RNAs (lncRNAs) as critical signaling nodes in diverse signaling networks. Defective signaling by lncRNAs is emerging as a causative factor underlying the pathophysiology of many diseases. LncRNAs have been shown to be involved in the multiplexed regulation of diverse pathways through both genetic and epigenetic mechanisms. They can serve as decoys, guides, scaffolds, and effector molecules to regulate cell signaling. In comparison with the other classes of RNAs, lncRNAs possess unique structural modifications that contribute to their diversity in modes of action within the nucleus and cytoplasm. In this review, we summarize the structure and function of lncRNAs as well as their vivid mechanisms of action. Further, we provide insights into the role of lncRNAs in the pathogenesis of four major disease paradigms, namely cardiovascular diseases, neurological disorders, cancers, and the metabolic disease, diabetes mellitus. This review serves as a succinct treatise that could open windows to investigate the role of lncRNAs as novel therapeutic targets.

H19 inhibition increases HDAC6 and regulates IRS1 levels and insulin signaling in the skeletal muscle during diabetes

Background

Histone deacetylases (HDACs) that catalyze removal of acetyl groups from histone proteins, are strongly associated with several diseases including diabetes, yet the precise regulatory events that control the levels and activity of the HDACs are not yet well elucidated.

Methods

Levels of H19 and HDACs were evaluated in skeletal muscles of normal and diabetic db/db mice by Western Blot analysis. C2C12 cells were differentiated and transfected with either the scramble or H19 siRNA and the levels of HDACs and Prkab2, Pfkfb3, Srebf1, Socs2, Irs1 and Ppp2r5b were assessed by Western Blot analysis and qRT-PCR, respectively. Levels of H9, HDAC6 and IRS1 were evaluated in skeletal muscles of scramble/ H19 siRNA injected mice and chow/HFD-fed mice.

Results

Our data show that the lncRNA H19 and HDAC6 exhibit inverse patterns of expression in the skeletal muscle of diabetic db/db mice and in C2C12 cells, H19 inhibition led to significant increase in HDAC activity and in the levels of HDAC6, both at the transcript and protein levels. This was associated with downregulation of IRS1 levels that were prevented in the presence of the HDAC inhibitor, SAHA, and HDAC6 siRNA suggesting the lncRNA H19-HDAC6 axis possibly regulates cellular IRS1 levels. Such patterns of H19, HDAC6 and IRS1 expression were also validated and confirmed in high fat diet-fed mice where as compared to normal chow-fed mice, H19 levels were significantly inhibited in the skeletal muscle of these mice and this was accompanied with elevated HDAC6 levels and decreased IRS1 levels. In-vivo inhibition of H19 led to significant increase in HDAC6 levels and this was associated with a decrease in IRS1 levels in the skeletal muscle.

Conclusions

Our results suggest a critical role for the lncRNA H19-HDAC6 axis in regulating IRS1 levels in the skeletal muscle during diabetes and therefore restoring normal H19 levels might hold a therapeutic potential for the management of aberrant skeletal muscle physiology during insulin resistance and type 2 diabetes.

Relationship between the Levels of lncRNA H19 in Plasma and Different Adipose Tissue Depots with Patients’ Response to Bariatric Surgery

Bariatric surgery represents a widespread approach to treating morbid obesity. The search for biomarkers to identify patients to whom this type of treatment will be most effective is needed. Our aim was to characterize the relationship of levels of lncRNA H19 in plasma and different adipose tissue depots with patients’ response to bariatric surgery. The study includes control subjects, patients with obesity and patients with obesity accompanied by impaired carbohydrate metabolism (ICM). Quantitative analysis of lncRNA H19 levels has been performed using qPCR in plasma and subcutaneous (SAT) and visceral adipose tissue (VAT). Patients with obesity without ICM have higher levels of lncRNA H19 in VAT compared to SAT, and higher levels of lncRNA H19 in SAT compared to SAT of control individuals. One year after the intervention, levels of lncRNA H19 decreased in SAT of patients with obesity without ICM. The preoperative level of lncRNA H19 in VAT demonstrates a positive correlation with excess weight loss and a negative correlation with initial BMI. In conclusion, ICM affects expression of lncRNA H19 in SAT of patients with obesity. The preoperative level of lncRNA H19 in VAT can be used to predict excess weight loss in patients with obesity after bariatric surgery.

A novel regulatory mechanism network mediated by lncRNA TUG1 that induces the impairment of spiral artery remodeling in Preeclampsia

Preeclampsia (PE) is associated with maternal and fetal perinatal morbidity and mortality, which brings tremendous suffering and imposes an economic burden worldwide. The failure of uterine spiral artery remodeling may be related to the abnormal function of trophoblasts and lead to the occurrence and progression of PE. Aberrant expression of long non-coding RNAs (lncRNAs) is involved in the failure of uterine spiral artery remodeling. However, the regulation of lncRNA expression in PE is poorly characterized. Here, we reported that hypoxia-induced microRNA (miR)-218 inhibited the expression of lncRNA TUG1 by targeting FOXP1. Further RNA sequencing and mechanism analysis revealed that silencing of TUG1 increased the expression of DNA demethylase TET3 and proliferation-related DUSP family, including DUSP2, DUSP4, and DUSP5, via binding to SUV39H1 in the nucleus. Moreover, TUG1 modulated the DUSP family in vitro through a TET3-mediated epigenetic mechanism. Taken together, our results unmask a new regulatory network mediated by TUG1 as an essential determinant of the pathogenesis of PE, which regulates cell growth and possibly the occurrence and development of other diseases.

Genetics, epigenetics and transgenerational transmission of obesity in children

Sedentary lifestyle and consumption of high-calorie foods have caused a relentless increase of overweight and obesity prevalence at all ages. Its presently epidemic proportion is disquieting due to the tight relationship of obesity with metabolic syndrome and several other comorbidities which do call for urgent workarounds. The usual ineffectiveness of present therapies and failure of prevention campaigns triggered overtime a number of research studies which have unveiled some relevant aspects of obesity genetic and epigenetic inheritable profiles. These findings are revealing extremely precious mainly to serve as a likely extra arrow to allow the clinician's bow to achieve still hitherto unmet preventive goals. Evidence now exists that maternal obesity/overnutrition during pregnancy and lactation convincingly appears associated with several disorders in the offspring independently of the transmission of a purely genetic predisposition. Even the pre-conception direct exposure of either father or mother gametes to environmental factors can reprogram the epigenetic architecture of cells. Such phenomena lie behind the transfer of the obesity susceptibility to future generations through a mechanism of epigenetic inheritance. Moreover, a growing number of studies suggests that several environmental factors such as maternal malnutrition, hypoxia, and exposure to excess hormones and endocrine disruptors during pregnancy and the early postnatal period may play critical roles in programming childhood adipose tissue and obesity. A deeper understanding of how inherited genetics and epigenetics may generate an obesogenic environment at pediatric age might strengthen our knowledge about pathogenetic mechanisms and improve the clinical management of patients. Therefore, in this narrative review, we attempt to provide a general overview of the contribution of heritable genetic and epigenetic patterns to the obesity susceptibility in children, placing a particular emphasis on the mother-child dyad.

Paternal Exercise Improves the Metabolic Health of Offspring via Epigenetic Modulation of the Germline

BACKGROUND/AIMS

Epigenetic regulation is considered the main molecular mechanism underlying the developmental origin of health and disease's (DOHAD) hypothesis. Previous studies that have investigated the role of paternal exercise on the metabolic health of the offspring did not control for the amount and intensity of the training or possible effects of adaptation to exercise and produced conflicting results regarding the benefits of parental exercise to the next generation. We employed a precisely regulated exercise regimen to study the transgenerational inheritance of improved metabolic health.

METHODS

We subjected male mice to a well-controlled exercise -training program to investigate the effects of paternal exercise on glucose tolerance and insulin sensitivity in their adult progeny. To investigate the molecular mechanisms of epigenetic inheritance, we determined chromatin markers in the skeletal muscle of the offspring and the paternal sperm.

RESULTS

Offspring of trained male mice exhibited improved glucose homeostasis and insulin sensitivity. Paternal exercise modulated the DNA methylation profile of PI3Kca and the imprinted H19/Igf2 locus at specific differentially methylated regions (DMRs) in the skeletal muscle of the offspring, which affected their gene expression. Remarkably, a similar DNA methylation profile at the PI3Kca, H19, and Igf2 genes was present in the progenitor sperm indicating that exercise-induced epigenetic changes that occurred during germ cell development contributed to transgenerational transmission.

CONCLUSION

Paternal exercise might be considered as a strategy that could promote metabolic health in the offspring as the benefits can be inherited transgenerationally.

Effect of lncRNA H19 on nerve degeneration and regeneration after sciatic nerve injury in rats

Hundreds of millions of people worldwide suffer from peripheral nerve damage resulting from car accidents, falls, industrial accidents, residential accidents, and wars. The purpose of our study was to further investigate the effects of Wallerian degeneration (WD) after rat sciatic nerve injury and to screen for critical long noncoding RNAs (lncRNAs) in WD. We found H19 to be essential for nerve degeneration and regeneration and to be highly expressed in the sciatic nerves of rats with WD. lncRNA H19 potentially impaired the recovery of sciatic nerve function in rats. H19 was mainly localized in the cytoplasm of Schwann cells (SCs) and promoted their migration. H19 promoted the apoptosis of dorsal root ganglion (DRG) neurons and slowed the growth of DRG axons. The lncRNA H19 may play a role in WD through the Wnt/β-catenin signaling pathway and is coexpressed with a variety of crucial mRNAs during WD. These data provide further insight into the molecular mechanisms of WD.

Long non-coding RNAs in metabolic disorders: pathogenetic relevance and potential biomarkers and therapeutic targets

BACKGROUND

It has been suggested that dysregulation of long non-coding RNAs (lncRNAs) could be associated with the incidence and development of metabolic disorders.

AIM

Accordingly, this narrative review described the molecular mechanisms of lncRNAs in the development of metabolic diseases including insulin resistance, diabetes, obesity, non-alcoholic fatty liver disease (NAFLD), cirrhosis, and coronary artery diseases (CAD). Furthermore, we investigated the up-to-date findings on the association of deregulated lncRNAs in the metabolic disorders, and potential use of lncRNAs as biomarkers and therapeutic targets.

CONCLUSION

LncRNAs/miRNA/regulatory proteins axis plays a crucial role in progression of metabolic disorders and may be used in development of therapeutic and diagnostic approaches.

Dihydroartemisinin regulates lipid droplet metabolism in hepatic stellate cells by inhibiting lncRNA-H19-induced AMPK signal

Activation of hepatic stellate cells (HSCs) is a central event in the pathogenesis of liver fibrosis and is often accompanied by the disappearance of lipid droplets (LDs). Although interference with LD metabolism can effectively reverse the activation of HSCs, there is currently no effective therapy for liver fibrosis. Our previous evidence indicates that long non-coding RNA (lncRNA)-H19 plays an essential role in LD metabolism of HSC. In this study, we investigated the potential molecular mechanism of dihydroartemisinin (DHA) inhibits LD metabolism and liver fibrosis by regulating H19-AMPK pathway. We found that DHA restores LDs content in activated HSCs via reducing the transcription of H19 driven by hypoxia inducible factor 1 subunit alpha (HIF1α) and inhibiting the lipid oxidation signal mediated by AMP-activated protein kinase (AMPK) phosphorylation. In vivo experiments, we have proved that DHA reduced the deposition of extracellular matrix (ECM) and reduce the level of liver fibrosis in CCl₄-induced liver fibrosis of mice. In summary, our results emphasize the importance of H19 in liver fibrosis and the potential of DHA to regulate H19 to treat liver fibrosis, providing a new direction for the prevention and treatment of liver fibrosis.

RNA sequencing reveals potential interacting networks between the altered transcriptome and ncRNome in the skeletal muscle of diabetic mice

For a global epidemic like Type 2 diabetes mellitus (T2DM), while impaired gene regulation is identified as a primary cause of aberrant cellular physiology; in the past few years, non-coding RNAs (ncRNAs) have emerged as important regulators of cellular metabolism. However, there are no reports of comprehensive in-depth cross-talk between these regulatory elements and the potential consequences in the skeletal muscle during diabetes. Here, using RNA sequencing, we identified 465 mRNAs and 12 long non-coding RNAs (lncRNAs), to be differentially regulated in the skeletal muscle of diabetic mice and pathway enrichment analysis of these altered transcripts revealed pathways of insulin, FOXO and AMP-activated protein kinase (AMPK) signaling to be majorly over-represented. Construction of networks showed that these pathways significantly interact with each other that might underlie aberrant skeletal muscle metabolism during diabetes. Gene-gene interaction network depicted strong interactions among several differentially expressed genes (DEGs) namely, Prkab2, Irs1, Pfkfb3, Socs2 etc. Seven altered lncRNAs depicted multiple interactions with the altered transcripts, suggesting possible regulatory roles of these lncRNAs. Inverse patterns of expression were observed between several of the deregulated microRNAs (miRNAs) and the differentially expressed transcripts in the tissues. Towards validation, overexpression of miR-381-3p and miR-539-5p in skeletal muscle C2C12 cells significantly decreased the transcript levels of their targets, Nfkbia, Pik3r1 and Pi3kr1, Cdkn2d, respectively. Collectively, the findings provide a comprehensive understanding of the interactions and cross-talk between the ncRNome and transcriptome in the skeletal muscle during diabetes and put forth potential therapeutic options for improving insulin sensitivity.

Role of Long Non-Coding RNAs and the Molecular Mechanisms Involved in Insulin Resistance

Long non-coding RNAs (lncRNAs) are single-stranded RNA biomolecules with a length of >200 nt, and they are currently considered to be master regulators of many pathological processes. Recent publications have shown that lncRNAs play important roles in the pathogenesis and progression of insulin resistance (IR) and glucose homeostasis by regulating inflammatory and lipogenic processes. lncRNAs regulate gene expression by binding to other non-coding RNAs, mRNAs, proteins, and DNA. In recent years, several mechanisms have been reported to explain the key roles of lncRNAs in the development of IR, including metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), imprinted maternal-ly expressed transcript (H19), maternally expressed gene 3 (MEG3), myocardial infarction-associated transcript (MIAT), and steroid receptor RNA activator (SRA), HOX transcript antisense RNA (HOTAIR), and downregulated Expression-Related Hexose/Glucose Transport Enhancer (DREH). LncRNAs participate in the regulation of lipid and carbohydrate metabolism, the inflammatory process, and oxidative stress through different pathways, such as cyclic adenosine monophosphate/protein kinase A (cAMP/PKA), phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT), polypyrimidine tract-binding protein 1/element-binding transcription factor 1c (PTBP1/SREBP-1c), AKT/nitric oxide synthase (eNOS), AKT/forkhead box O1 (FoxO1), and tumor necrosis factor-alpha (TNF-α)/c-Jun-N-terminal kinases (JNK). On the other hand, the mechanisms linked to the molecular, cellular, and biochemical actions of lncRNAs vary according to the tissue, biological species, and the severity of IR. Therefore, it is essential to elucidate the role of lncRNAs in the insulin signaling pathway and glucose and lipid metabolism. This review analyzes the function and molecular mechanisms of lncRNAs involved in the development of IR.

Dysregulation of lncRNA-H19 in cardiometabolic diseases and the molecular mechanism involved : a systematic review

Introduction: Cardiometabolic diseases are a global public health problem, with significant increases in their prevalence. Different epigenetic factors involved in the progression of metabolic alterations have been described, such as long non-coding RNAs (lncRNAs). H19 is a multifunctional lncRNA expressed from the maternal allele, with low expression after birth, except in the skeletal muscle and heart. Recent studies have linked its dysregulation to alterations in cell metabolism.Areas covered: H19 plays a role in the pathogenesis of coronary artery disease, nonalcoholic fatty liver disease, hepatic and renal fibrosis, insulin resistance, type 2 diabetes, and inflammation. H19 acts mainly as a competitive endogenous RNA of molecules involved in pathways that regulate cell metabolism. In this review, we analyzed the dysregulation of H19 in cardiometabolic diseases and its relationship with molecular alterations in different signaling pathways.Expert opinion: The association of H19 with the development of cardiometabolic diseases, indicates that H19 could be a therapeutic target and prognostic biomarker for these diseases. Controversies have been reported regarding the expression of H19 in some metabolic diseases, therefore, it is necessary to continue research to clarify its pathogenic effect in different organs.

LncRNA H19 induces immune dysregulation of BMMSCs, at least partly, by inhibiting IL-2 production

BACKGROUND

Systemic lupus erythematosus (SLE) is a representative systemic autoimmune disease. LncRNA H19 has been identified to participate in various biological processes in human diseases. However, the role of H19 in SLE remains unclear.

METHODS

In this study, we first examined H19 expression in SLE patients by RT-qPCR and found that H19 expression was significantly upregulated in the serum and bone marrow-derived mesenchymal stem cells (BMMSCs) of SLE patients and positively associated with SLE disease activity index. We then performed gain-of-function and loss-of-function using mimic-H19 (H19-OE) and inhibitor-H19 (H19-KD) to examine the effects of H19 on BMMSC differentiation, proliferation, migration, and apoptosis using flow cytometry, DAPI staining, and migration and apoptosis assays.

RESULTS

The results showed that H19 inhibited proliferation and migration but promoted apoptosis of BMMSCs, interfered with BMMSCs-mediated Treg cell proliferation and differentiation, and regulated BMMSCs-mediated Tfh/Treg cell balance. Dual-luciferase reporter assay confirmed the in silico prediction of interaction between H19 and IL-2. Furthermore, RT-qPCR showed that H19 directly inhibited IL-2 transcription in BMMSCs. ELISA showed that both active and total IL-2 protein levels were significantly lower in SLE BMMSCs. More importantly, we found that IL-2 significantly enhanced H19-OE-induced Treg cell differentiation and migration of BMMSCs, and these effects were reversed by anti-IL-2 antibody.

CONCLUSION

Overall, our study indicates that LncRNA H19 induces immune dysregulation of BMMSCs, at least partly, by inhibiting IL-2 production and might be a novel therapeutic target for SLE.

Novel model of restricted mobility induced osteopenia in zebrafish

Immobilization, such as prolonged bed rest, is a risk factor for bone loss in humans. Motivated by the emerging utility of zebrafish (Danio rerio) as an animal of choice for the study of musculoskeletal disease, here we report a model of restricted mobility induced osteopenia in adult zebrafish. Aquatic tanks with small cubical compartments to restrict the movement and locomotion of single fish were designed and fabricated for this study. Adult zebrafish were divided into two groups: a normal control (CONT) and a restricted mobility group (RMG) (18 fish/group). Six fish from each group were euthanized on days 14, 21 and 35 of the movement restriction. By using microcomputed tomography (micro-CT), we assessed bone volume/tissue volume (BV/TV) and bone density in the whole skeleton of the fish. Furthermore, we assessed skeletal shape in the vertebrae (radius, length, volume, neural and haemal arch aperture areas, neural and haemal arch angle, and thickness of the intervertebral space), single vertebra bone volume and bone density. Movement restriction significantly decreased vertebral skeletal parameters such as radius, length, volume, arch aperture areas and angles as well as the thickness of the intervertebral space in RMG. Furthermore, restricted mobility significantly (P < 0.001) decreased BV/TV and bone density as compared to the CONT group, starting as early as 14 days. By analysing zebrafish from CONT and RMG, we show that micro-CT imaging is a sensitive method to quantify distinct skeletal properties in zebrafish. We further defined the micro-CT parameters which can be used to examine the effects of restricted mobility on the skeleton of the fish. Our findings propose a rapid and effective osteopenia "stabulation" model, which could be used widely for osteoporosis drug screening.

Danthron ameliorates obesity and MAFLD through activating the interplay between PPARα/RXRα heterodimer and adiponectin receptor 2

Obesity and associated metabolic associated fatty liver diseases (MAFLD) are strongly associated with dysfunction of glucose and lipid metabolism. AMPKα and PPARα are key regulators in the lipid and glucose homeostasis, indicating that novel agents to activate them are promising therapeutic approaches for metabolic syndrome. Noticeably, as a natural anthraquinone derivative extracted from rhubarb, danthron can activate AMPKα in vitro. However, the protective effect of danthron on obesity and associated MAFLD in vivo, as well as the underlying mechanism remains unknown. In this study, obesity and associated MAFLD was induced in C57BL/6J mice by high fat diet (HFD), which were subjected to evaluations on the parameters of systematic metabolism. Simultaneously, the molecular mechanism of danthron on lipid metabolism was investigated in 3T3-L1-derived adipocytes and HepG2 cells in vitro. In vivo, danthron significantly attenuated the obesity and MAFLD by enhancing hepatic fatty acid oxidation, decreasing lipid synthesis, and promoting mitochondrial homeostasis. Mechanistically, danthron significantly promoted combination of RXRα and PPARα, enhanced the binding of RXRα/PPARα heterodimer to the promoter of adiponectin receptor 2 (AdipoR2), by which activating the AMPKα and PPARα pathway. Moreover, PPARα and AdipoR2 can interplay in a loop style. Collectively, this study demonstrates that danthron can substantially ameliorate obesity and associated hepatic steatosis via AdipoR2-mediated dual PPARα/AMPKα activation, which suggests that danthron might be a novel therapeutic approach for inhibition of obesity and hepatic steatosis.

Lnc-ORA interacts with microRNA-532-3p and IGF2BP2 to inhibit skeletal muscle myogenesis

Skeletal muscle is one of the most important organs of the animal body. Long noncoding RNAs play a crucial role in the regulation of skeletal muscle development via several mechanisms. We recently identified obesity-related lncRNA (lnc-ORA) in a search for long noncoding RNAs that influence adipogenesis, finding it impacted adipocyte differentiation by regulating the PI3K/protein kinase B/mammalian target of rapamycin pathway. However, whether lnc-ORA has additional roles, specifically in skeletal muscle myogenesis, is not known. Here, we found that lnc-ORA was significantly differentially expressed with age in mouse skeletal muscle tissue and predominantly located in the cytoplasm. Overexpression of lnc-ORA promoted C2C12 myoblast proliferation and inhibited myoblast differentiation. In contrast, lnc-ORA knockdown repressed myoblast proliferation and facilitated myoblast differentiation. Interestingly, silencing of lnc-ORA rescued dexamethasone-induced muscle atrophy in vitro. Furthermore, adeno-associated virus 9–mediated overexpression of lnc-ORA decreased muscle mass and the cross-sectional area of muscle fiber by upregulating the levels of muscle atrophy–related genes and downregulating the levels of myogenic differentiation–related genes in vivo. Mechanistically, lnc-ORA inhibited skeletal muscle myogenesis by acting as a sponge of miR-532-3p, which targets the phosphatase and tensin homolog gene; the resultant changes in phosphatase and tensin homolog suppressed the PI3K/protein kinase B signaling pathway. In addition, lnc-ORA interacted with insulin-like growth factor 2 mRNA-binding protein 2 and reduced the stability of myogenesis genes, such as myogenic differentiation 1 and myosin heavy chain. Collectively, these findings indicate that lnc-ORA could be a novel underlying regulator of skeletal muscle development.

Long Non-Coding RNAs (lncRNAs) in Cardiovascular Disease Complication of Type 2 Diabetes

The discovery of non-coding RNAs (ncRNAs) has opened a new paradigm to use ncRNAs as biomarkers to detect disease progression. Long non-coding RNAs (lncRNA) have garnered the most attention due to their specific cell-origin and their existence in biological fluids. Type 2 diabetes patients will develop cardiovascular disease (CVD) complications, and CVD remains the top risk factor for mortality. Understanding the lncRNA roles in T2D and CVD conditions will allow the future use of lncRNAs to detect CVD complications before the symptoms appear. This review aimed to discuss the roles of lncRNAs in T2D and CVD conditions and their diagnostic potential as molecular biomarkers for CVD complications in T2D.

Benzyl Butyl Phthalate Induced Early lncRNA H19 Regulation in C3H10T1/2 Stem Cell Line

Exposure to endocrine-disrupting chemicals used in plastic manufacturing may contribute to the current obesity and diabetes epidemic. Our previous study demonstrated that benzyl butyl phthalate (BBP) induced adipogenesis in the C3H10T1/2 stem cell line. Here we investigated if BBP deregulated long noncoding RNA H19 and its downstream pathway and whether BBP plays a role in the insulin signaling pathway during adipocyte diiferentiation. Cells treated with an 8 day BBP regimen showed that H19 expression was decreased at day 2 with 50 μM BBP exposure (p < 0.05). However, no significant changes were observed from day 4 to day 8. Expression of miRNA-103/107, H19 regulated miRNAs, was upregulated at day 2 (p < 0.05) but not from day 4 to day 8. Similarly, expression of the let-7 family members (a, b, c, d, f, and g) was also significantly increased at day 2 (p < 0.05 or p < 0.01), except for let-7e. Both let-7 and miRNA-103/107 are targets of H19 and play roles in insulin signaling. Insulin receptor substrate (IRS)-1, one of the key insulin signal transduction regulators, was significantly downregulated from day 2 to day 8 (p < 0.05). Gene expression of insulin receptor (IR) and IRS-2 were not altered by BBP exposure. The ratio of IRS1/IRS2 was significantly decreased from day 2 to day 8. On day 4, phospho-Akt protein expression was significantly decreased (p < 0.05). In conclusion, BBP exposure may lead to metabolic dysregulation by altering vital epigenetic regulators such as lncRNA H19 and its target microRNAs at an earlier stage, which further regulates insulin signaling.

Association of Genetic Variants in IGF2-Related Genes With Risk of Metabolic Syndrome in the Chinese Han Population

AIMS

To explore associations between polymorphisms of IGF2-related genes including H19, IGF2, IGF2BP2 and IGF2R and Metabolic syndrome (MetS) susceptibility in the Chinese Han population.

METHODS

66 subjects with MetS and 257 control subjects were collected for inclusion in a case-control study. PCR-RFLP was used to investigate polymorphisms in the H19, IGF2, IGF2BP2 and IGF2R genes. Elisa was used to detect the serum IGF2 concentrations.

RESULTS

Females carrying the GG and AG genotypes of rs680 (IGF2) exhibited a lower risk of MetS, compared with those harboring AA (adjusted OR = 0.388, p = 0.027), while GG and AG genotypes were associated with lower fasting glucose and HbA1c. In males, the Waist-to-Hip Ratio (WHR) and the level of TG were significantly higher in GG and AG genotypes than in the AA genotype of rs680 in IGF2. Levels of HDL-c were lower in men with GG and AG genotypes compared with those carrying the AA genotype. Serum IGF2 concentrations did not change among different genotypes. Finally, multifactor dimensionality reduction (MDR) analysis identified interactions between four polymorphisms: rs3741279 (H19), rs680 (IGF2), rs1470579 (IGF2BP2) and rs629849 (IGF2R).

CONCLUSIONS

Our study suggests that IGF2-related genes including H19, IGF2, IGF2BP2 and IGF2R genes may play pivotal roles in the development of MetS.

RNA-sequencing analysis reveals the potential contribution of lncRNAs in palmitic acid-induced insulin resistance of skeletal muscle cells

Insulin resistance (IR) has been considered as the common pathological basis and developmental driving force for most metabolic diseases. Long noncoding RNAs (lncRNAs) have emerged as pivotal regulators in modulation of glucose and lipid metabolism. However, the comprehensive profile of lncRNAs in skeletal muscle cells under the insulin resistant status and the possible biological effects of them were not fully studied. In this research, using C2C12 myotubes as cell models in vitro, deep RNA-sequencing was performed to profile lncRNAs and mRNAs between palmitic acid-induced IR C2C12 myotubes and control ones. The results revealed that a total of 144 lncRNAs including 70 up-regulated and 74 down-regulated (|fold change| > 2, q < 0.05) were significantly differentially expressed in palmitic acid-induced insulin resistant cells. In addition, functional annotation analysis based on the Gene Ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) databases revealed that the target genes of the differentially expressed lncRNAs were significantly enriched in fatty acid oxidation, lipid oxidation, PPAR signaling pathway, and insulin signaling pathway. Moreover, Via qPCR, most of selected lncRNAs in myotubes and db/db mice skeletal muscle showed the consistent expression trends with RNA-sequencing. Co-expression analysis also explicated the key lncRNA–mRNA interactions and pointed out a potential regulatory network of candidate lncRNA ENSMUST00000160839. In conclusion, the present study extended the skeletal muscle lncRNA database and provided novel potential regulators for future genetic and molecular studies on insulin resistance, which is helpful for prevention and treatment of the related metabolic diseases.

LncRNAH19 improves insulin resistance in skeletal muscle by regulating heterogeneous nuclear ribonucleoprotein A1

Background

Skeletal muscle is essential for glucose and lipid metabolism. Growing evidence reveals the importance of long non-coding RNAs (LncRNAs) in metabolism. This study aimed to investigate the function of LncRNA H19 (H19) in lipid metabolism of skeletal muscle and its potential mechanisms.

Methods

Glucose tolerance, serum insulin and lipid content in serum and skeletal muscle were determined in control and H19-overexpressed db/db mice. Lipid metabolism was evaluated in H19-overexpressed or H19-silencing muscle cells by detecting lipid contents and mitochondria related functions. The underlying mechanisms were explored by RNA pull-down, mass spectrometry and RNA immunoprecipitation (RIP).

Results

H19 was downregulated in skeletal muscle of db/db mice. H19 overexpression in db/db mice inhibited lipid ectopic deposition in skeletal muscle, meanwhile improved glucose intolerance and insulin resistance as compared with control db/db mice treated with ad-GFP. Furthermore, overexpression of H19 reversed FFA-induced lipid accumulation and increased cellular respiration in muscle cells, while H19 knockdown exhibited opposite effects in muscle cells. Mechanistically, H19 interacted with heterogeneous nuclear ribonucleoprotein (hnRNPA1) which was validated by RNA pulldown and RIP analysis, which increased translation of fatty acid oxidation closely related genes PGC1a and CPT1b.

Conclusion

Our data suggest that overexpression of H19 ameliorates insulin resistance by reducing ectopic lipid accumulation in skeletal muscle. The possible underlying mechanisms are that overexpression of lncRNAH19 promotes fatty acids oxidation via targeting of hnRNPA1.

Cells of the adult human heart

Cardiovascular disease is the leading cause of death worldwide. Advanced insights into disease mechanisms and therapeutic strategies require a deeper understanding of the molecular processes involved in the healthy heart. Knowledge of the full repertoire of cardiac cells and their gene expression profiles is a fundamental first step in this endeavour. Here, using state-of-the-art analyses of large-scale single-cell and single-nucleus transcriptomes, we characterize six anatomical adult heart regions. Our results highlight the cellular heterogeneity of cardiomyocytes, pericytes and fibroblasts, and reveal distinct atrial and ventricular subsets of cells with diverse developmental origins and specialized properties. We define the complexity of the cardiac vasculature and its changes along the arterio-venous axis. In the immune compartment, we identify cardiac-resident macrophages with inflammatory and protective transcriptional signatures. Furthermore, analyses of cell-to-cell interactions highlight different networks of macrophages, fibroblasts and cardiomyocytes between atria and ventricles that are distinct from those of skeletal muscle. Our human cardiac cell atlas improves our understanding of the human heart and provides a valuable reference for future studies.

Long Non-coding RNAs Are Differentially Expressed After Different Exercise Training Programs

Background

Molecular regulation related to the health benefits of different exercise modes remains unclear. Long non-coding RNAs (lncRNAs) have emerged as an RNA class with regulatory functions in health and diseases. Here, we analyzed the expression of lncRNAs after different exercise training programs and their possible modes of action related to physical exercise adaptations.

Methods

Public high-throughput RNA-seq data (skeletal muscle biopsies) were downloaded, and bioinformatics analysis was performed. We primarily analyzed data reports of 12 weeks of resistance training (RT), high-intensity interval training (HIIT), and combined (CT) exercise training. In addition, we analyzed data from 8 weeks of endurance training (ET). Differential expression analysis of lncRNAs was performed, and an adjusted P-value < 0.1 and log2 (fold change) ≥0.5 or ≤-0.5 were set as the cutoff values to identify differentially expressed lncRNAs (DELs).

Results

We identified 204 DELs after 12 weeks of HIIT, 43 DELs after RT, and 15 DELs after CT. Moreover, 52 lncRNAs were differentially expressed after 8 weeks of ET. The lncRNA expression pattern after physical exercise was very specific, with distinct expression profiles for the different training programs, where few lncRNAs were common among the exercise types. LncRNAs may regulate molecular responses to exercise, such as collagen fibril organization, extracellular matrix organization, myoblast and plasma membrane fusion, skeletal muscle contraction, synaptic transmission, PI3K and TORC regulation, autophagy, and angiogenesis.

Conclusion

For the first time, we show that lncRNAs are differentially expressed in skeletal muscle after different physical exercise programs, and these lncRNAs may act in various biological processes related to physical activity adaptations.

HIF-1α-upregulated lncRNA-H19 regulates lipid droplet metabolism through the AMPKα pathway in hepatic stellate cells

Activation of hepatic stellate cells (HSCs) is a central event in the pathogenesis of liver fibrosis and is characterized by the disappearance of lipid droplets. Although the exogenous supplementation of lipid droplet content can effectively reverse the activation of HSCs, the underlying molecular mechanisms are largely unknown. In our current study, we sought to investigate the role of lncRNA-H19 in the process of lipid droplets disappearance and to further examine the underlying molecular mechanisms. We found that the lncRNA-H19 level was increased in CCl4-induced fibrotic liver, which activated HSCs. Further research showed that hypoxia inducible factor-1α (HIF-1α) significantly increased lncRNA-H19 expression by binding to the lncRNA-H19 promoter at two hypoxia response element (HRE) sites located at 492-499 and 515-522 bp. Importantly, lncRNA-H19 knockdown markedly inhibited HSC activation and alleviated liver fibrosis, indicating that lncRNA-H19 may be a potential target for anti-fibrosis therapeutic approaches. Moreover, lncRNA-H19 knockdown could reverse the lipid droplet phenotype of activated HSCs, inhibiting the phosphorylated AMPKα-mediated lipid oxidation signaling pathway. The AMPK agonist AICAR promoted AMPKα phosphorylation and abrogated lipid droplets restoration in HSCs transfected with the lncRNA-H19 knockdown plasmid. Experimental molecular analysis showed that lncRNA-H19 triggered AMPKα to interact with LKB1 and resulted in AMPKα phosphorylation, which accelerating lipid droplets degradation and lipid oxidation. Taken together, our results highlighted the role of lncRNA-H19 in the metabolism of lipid droplets in HSCs, and revealed a new molecular target for alleviating liver fibrosis.