The m6A methyltransferase METTL3 regulates muscle maintenance and growth in mice.

Skeletal muscle serves fundamental roles in organismal health. Gene expression fluctuations are critical for muscle homeostasis and the response to environmental insults. Yet, little is known about post-transcriptional mechanisms regulating such fluctuations while impacting muscle proteome. Here we report genome-wide analysis of mRNA methyladenosine (m6A) dynamics of skeletal muscle hypertrophic growth following overload-induced stress. We show that increases in METTL3 (the m6A enzyme), and concomitantly m6A, control skeletal muscle size during hypertrophy; exogenous delivery of METTL3 induces skeletal muscle growth, even without external triggers. We also show that METTL3 represses activin type 2 A receptors (ACVR2A) synthesis, blunting activation of anti-hypertrophic signaling. Notably, myofiber-specific conditional genetic deletion of METTL3 caused spontaneous muscle wasting over time and abrogated overload-induced hypertrophy; a phenotype reverted by co-administration of a myostatin inhibitor. These studies identify a previously unrecognized post-transcriptional mechanism promoting the hypertrophic response of skeletal muscle via control of myostatin signaling.

Chemokine (C-C Motif) Ligand 2/Chemokine Receptor 2 (CCR2) Axis Blockade to Delay Chondrocyte Hypertrophy as a Therapeutic Strategy for Osteoarthritis.

BACKGROUND Chondrocytes play a vital role in the later stages of osteoarthritis (OA). The roles of chemokine (C-C motif) ligand 2 (CCL2) and its receptor, chemokine receptor 2 (CCR2), are as yet poorly elucidated in chondrocyte hypertrophy (CH). Here, we aimed to regulate the CCL2/CCR2 axis and explore its effect on progression of CH. MATERIAL AND METHODS Chondrocytes isolated from patients with OA were used in the present study. In vitro experiments were conducted to test hypertrophic gene and CCL2/CCR2 expression in chondrocyte degeneration caused by interleukin (IL)-17A or CCL2 protein stimulation. In addition, inhibition of CCL2 and CCR2 was used to assess the role of CCL2 and CCR2 blockade in CH. Relative gene expression was determined with real-time polymerase chain reaction, western blot, or immunofluorescence. Hypertrophic changes were assessed with cell area measurement. Moreover, the viability of chondrocytes was analyzed using an MTT assay and flow cytometry was used to assess cell apoptosis. RESULTS CCL2 and CCR2 were upregulated in IL-17A-treated chondrocytes. The exogenic CCL2 stimulation also promoted CH and increased the expression of Type 10 collagen, RUNX2, and IHH, which could be reversed via suppression of CCR2. Inhibition of CCL2 and CCR2 expression was sufficient to: 1) protect Type 2 collagen synthesis; 2) alleviate IL-17A-induced overexpression of Type 10 collagen, RUNX2, and IHH; and 3) improve chondrocyte proliferation and apoptosis. CONCLUSIONS Blockading the CCL2/CCR2 axis plays a role in delaying the development of CH.

Critical timing of ACEi initiation prevents compensatory glomerular hypertrophy in the remaining single kidney.

Increasing evidence suggests that single in kidney states (e.g., kidney transplantation and living donation) progressive glomerulosclerosis limits kidney lifespan. Modeling shows that post-nephrectomy compensatory glomerular volume (GV) increase drives podocyte depletion and hypertrophic stress resulting in proteinuria and glomerulosclerosis, implying that GV increase could serve as a therapeutic target to prevent progression. In this report we examine how Angiotensin Converting Enzyme inhibition (ACEi), started before uninephrectomy can reduce compensatory GV increase in wild-type Fischer344 rats. An unbiased computer-assisted method was used for morphometric analysis. Urine Insulin-like growth factor-1 (IGF-1), the major diver of body and kidney growth, was used as a readout. In long-term (40-week) studies of uni-nephrectomized versus sham-nephrectomized rats a 2.2-fold increase in GV was associated with reduced podocyte density, increased proteinuria and glomerulosclerosis. Compensatory GV increase was largely prevented by ACEi started a week before but not after uni-nephrectomy with no measurable impact on long-term eGFR. Similarly, in short-term (14-day) studies, ACEi started a week before uni-nephrectomy reduced both GV increase and urine IGF-1 excretion. Thus, timing of ACEi in relation to uni-nephrectomy had significant impact on post-nephrectomy "compensatory" glomerular growth and outcomes that could potentially be used to improve kidney transplantation and live kidney donation outcomes.

Improvement Effect of Sweet Basil (Ocimum basilicum L.) Powder Intake on Obese Mice Fed a High-fat and High-sucrose Diet.

This study aimed to determine if there are anti-inflammatory and anti-obesity effects of sweet basil, an herb, in mice. Sweet basil was administered as a powder to male C57BL/6JJcl mice, which were divided into three groups: the (control [C], high-fat and high-sucrose diet [H], and high-fat and high-sucrose diet plus sweet basil powder [HB]) groups. The mice were fed for 12 weeks and the dry sweet basil powder comprised 1% per kg of the diet. From experiment third week, the average body weight was significantly higher in the H group than in the C group. The average body weight was significantly lower in the HB group than in the H group, but food intake did not significantly differ between the H and HB groups. Liver weight was drastically lower in the HB group than in the H group. Perirenal fat weight and epididymal fat weight were not significantly different between the H and HB groups. Therefore, we assumed that body-weight reduction caused by sweet basil powder intake depended on inhibition of liver enlargement. We then examined lipid metabolism-related gene expression in the mice livers. Expression of the sterol response element binding protein 1-c gene tended to be lower in the HB group than in the H group (p=0.056). We speculated that sweet basil inhibited liver enlargement by suppressing fatty acid synthesis. Moreover, expression of the monocyte chemoattractant protein-1 gene in epididymal fat was significantly lower in the HB group than in the H group. Sweet basil powder appears to have a potent anti-inflammatory effect in the adipose tissue of mice fed a high-fat and high-sucrose diet.

miR-10396b-3p inhibits mechanical stress-induced ligamentum flavum hypertrophy by targeting IL-11.

Ligamentum flavum hypertrophy (LFH) leads to lumbar spinal stenosis (LSS) caused by LF tissue inflammation and fibrosis. Emerging evidence has indicated that dysregulated microRNAs (miRNAs) have an important role in inflammation and fibrosis. Mechanical stress (MS) has been explored as an initiating step in LFH pathology progression; the inflammation-related miRNAs induced after mechanical stress have been implicated in fibrosis pathology. However, the pathophysiological mechanism of MS-miRNAs-LFH remains to be elucidated. Using miRNAs sequencing analysis and subsequent confirmation with qRT-PCR assays, we identified the decreased expression of miR-10396b-3p and increased expression of IL-11 (interleukin-11) as responses to the development of LSS in hypertrophied LF tissues. We also found that IL-11 is positively correlated with fibrosis indicators of collagen I and collagen III. The up-regulation of miR-10396b-3p significantly decreased the level of IL-11 expression, whereas miR-10396b-3p down-regulation increased IL-11 expression in vitro. Luciferase reporter assay indicates that IL-11 is a direct target of miR-10396b-3p. Furthermore, cyclic mechanical stress inhibits miR-10396b-3p and induces IL-11, collagen I, and collagen III in vitro. Our results showed that overexpression of miR-10396b-3p suppresses MS-induced LFH by inhibiting collagen I and III via the inhibition of IL-11. These data suggest that the MS-miR-10396b-3p-IL-11 axis plays a key role in the pathological progression of LFH.

Cinacalcet may suppress kidney enlargement in hemodialysis patients with autosomal dominant polycystic kidney disease.

A massively enlarged kidney can impact quality of life of autosomal dominant polycystic kidney disease (ADPKD) patients. A recent in vitro study demonstrated that an allosteric modulator of the calcium sensing receptor decreases adenosine-3',5'-cyclic monophosphate, an important factor for kidney enlargement in ADPKD. Therefore, the present study was performed to determine whether cinacalcet, a calcium sensing receptor agonist, suppresses kidney enlargement in hemodialysis patients with ADPKD. Alteration of total kidney volume together with clinical parameters was retrospectively examined in 12 hemodialysis patients with ADPKD treated at a single institution in Japan. In the non-cinacalcet group with longer hemodialysis duration (n = 5), total kidney volume had an annual increase of 4.19 ± 1.71% during an overall period of 877 ± 494 days. In contrast, the annual rate of increase in total kidney volume in the cinacalcet group (n = 7) was significantly suppressed after cinacalcet treatment, from 3.26 ± 2.87% during a period of 734 ± 352 days before the start of cinacalcet to - 4.71 ± 6.42% during 918 ± 524 days after initiation of treatment (p = 0.047). The present findings showed that cinacalcet could be a novel therapeutic tool for suppression of kidney enlargement in hemodialysis patients with ADPKD.

Maternal tadalafil therapy for fetal growth restriction prevents non-alcoholic fatty liver disease and adipocyte hypertrophy in the offspring.

We aimed to investigate the effects of maternal tadalafil therapy on fetal programming of metabolic function in a mouse model of fetal growth restriction (FGR). Pregnant C57BL6 mice were divided into the control, L-NG-nitroarginine methyl ester (L-NAME), and tadalafil + L-NAME groups. Six weeks after birth, the male pups in each group were given a high-fat diet. A glucose tolerance test (GTT) was performed at 15 weeks and the pups were euthanized at 20 weeks. We then assessed the histological changes in the liver and adipose tissue, and the adipocytokine production. We found that the non-alcoholic fatty liver disease activity score was higher in the L-NAME group than in the control group (p < 0.05). Although the M1 macrophage numbers were significantly higher in the L-NAME/high-fat diet group (p < 0.001), maternal tadalafil administration prevented this change. Moreover, the epididymal adipocyte size was significantly larger in the L-NAME group than in the control group. This was also improved by maternal tadalafil administration (p < 0.05). Further, we found that resistin levels were significantly lower in the L-NAME group compared to the control group (p < 0.05). The combination of exposure to maternal L-NAME and a high-fat diet induced glucose impairment and non-alcoholic fatty liver disease. However, maternal tadalafil administration prevented these complications. Thus, deleterious fetal programming caused by FGR might be modified by in utero intervention with tadalafil.

Oroxylin A attenuates osteoarthritis progression by dual inhibition of cell inflammation and hypertrophy.

The imbalance between the anabolism and catabolism of the extracellular matrix (ECM) is of great importance to osteoarthritis (OA) development. Aberrant inflammatory responses and hypertrophic changes of chondrocytes are the main contributors to these metabolic disorders. In the present study, we found that Oroxylin A (ORA), a flavonoid compound derived from Oroxylum indicum, maintained ECM hemostasis of chondrocytes by Interleukin-1ß (IL-1ß) stimulation. Besides, it was demonstrated that IL-1ß induced over-production of inflammatory mediators was attenuated by ORA treatment. Moreover, ORA could rescue IL-1ß mediated hypertrophic alterations of chondrocytes. Mechanistically, ORA's protective effects were found to be associated with both NF-κB and Wnt/ß-catenin signaling inhibition. Meanwhile, molecular docking analysis revealed that ORA could strongly bind to the inhibitor kappa B kinaseß (IKKß) and dishevelled, Dsh Homolog 2 (Dvl2), the upstream molecules of the NF-κB axis and ß-catenin axis, respectively. In addition, ORA driven chondroprotective effects were also affirmed in a surgically induced OA mouse model. Taken together, the current study suggested that ORA might be a promising therapeutic option for the treatment of OA.

Matrilin-3-Primed Adipose-Derived Mesenchymal Stromal Cell Spheroids Prevent Mesenchymal Stromal-Cell-Derived Chondrocyte Hypertrophy.

Adipose-derived mesenchymal stromal cells (Ad-MSCs) are a promising tool for articular cartilage repair and regeneration. However, the terminal hypertrophic differentiation of Ad-MSC-derived cartilage is a critical barrier during hyaline cartilage regeneration. In this study, we investigated the role of matrilin-3 in preventing Ad-MSC-derived chondrocyte hypertrophy in vitro and in an osteoarthritis (OA) destabilization of the medial meniscus (DMM) model. Methacrylated hyaluron (MAHA) (1%) was used to encapsulate and make scaffolds containing Ad-MSCs and matrilin-3. Subsequently, the encapsulated cells in the scaffolds were differentiated in chondrogenic medium (TGF-ß, 1-14 days) and thyroid hormone hypertrophic medium (T3, 15-28 days). The presence of matrilin-3 with Ad-MSCs in the MAHA scaffold significantly increased the chondrogenic marker and decreased the hypertrophy marker mRNA and protein expression. Furthermore, matrilin-3 significantly modified the expression of TGF-ß2, BMP-2, and BMP-4. Next, we prepared the OA model and transplanted Ad-MSCs primed with matrilin-3, either as a single-cell suspension or in spheroid form. Safranin-O staining and the OA score suggested that the regenerated cartilage morphology in the matrilin-3-primed Ad-MSC spheroids was similar to the positive control. Furthermore, matrilin-3-primed Ad-MSC spheroids prevented subchondral bone sclerosis in the mouse model. Here, we show that matrilin-3 plays a major role in modulating Ad-MSCs' therapeutic effect on cartilage regeneration and hypertrophy suppression.

Increasing carbohydrate oxidation improves contractile reserves and prevents hypertrophy in porcine right heart failure.

In heart failure, myocardial overload causes vast metabolic changes that impair cardiac energy production and contribute to deterioration of contractile function. However, metabolic therapy is not used in heart failure care. We aimed to investigate the interplay between cardiac function and myocardial carbohydrate metabolism in a large animal heart failure model. Using magnetic resonance spectroscopy with hyperpolarized pyruvate and magnetic resonance imaging at rest and during pharmacological stress, we investigated the in-vivo cardiac pyruvate metabolism and contractility in a porcine model of chronic pulmonary insufficiency causing right ventricular volume overload. To assess if increasing the carbohydrate metabolic reserve improves the contractile reserve, a group of animals were fed dichloroacetate, an activator of pyruvate oxidation. Volume overload caused heart failure with decreased pyruvate dehydrogenase flux and poor ejection fraction reserve. The animals treated with dichloroacetate had a larger contractile response to dobutamine stress than non-treated animals. Further, dichloroacetate prevented myocardial hypertrophy. The in-vivo metabolic data were validated by mitochondrial respirometry, enzyme activity assays and gene expression analyses. Our results show that pyruvate dehydrogenase kinase inhibition improves the contractile reserve and decreases hypertrophy by augmenting carbohydrate metabolism in porcine heart failure. The approach is promising for metabolic heart failure therapy.

Novel hyaluronan formulation for preventing acute skin reactions in breast during radiotherapy: a randomized clinical trial.

PURPOSE: We conducted a randomized, double-blind, vehicle-controlled clinical trial to investigate the use of a new proprietary hyaluronan (HA) formulation for the prevention of acute skin toxicity in breast cancer patients undergoing radiotherapy (RT). METHODS: Thirty women with breast cancer undergoing whole breast RT were enrolled. Each patient was randomly assigned to HA formulation (study cream, S) on the medial or lateral half of the irradiated breast and the control cream (placebo, P) on the other half. The primary endpoint was physician's evaluation of skin symptoms at week 5 during RT and week 2 post-RT. We also collected patients' independent assessment of skin after RT, patient's product preference, and an independent physician panel assessment of skin reactions based on photographs. RESULTS: Twenty-eight patients were evaluable. On physician's evaluation, there was no significant difference in radiation dermatitis between S and P and no overall preference to either cream at week 5 during or week 2 post-RT. More patients preferred S in evaluating skin appearance and skin reactions, but this did not reach statistical significance. Univariate analysis showed that physicians had an overall preference to the S cream at week 2 post-RT in patients with larger breasts. On the independent panel assessment, 3 reviewers saw no significant difference in radiation toxicity, whereas one reviewer reported better skin outcome with S cream at week 5. CONCLUSIONS: We found a nonstatistically significant patient preference but overall no significant radioprotective effects for this HA formulation compared with placebo except in patients with larger breasts. TRIAL REGISTRATION: The study was registered at www.clinicaltrials.gov (NCT02165605).

Selective occlusion of the hepatic artery and portal vein improves liver hypertrophy for staged hepatectomy.

BACKGROUND: To evaluate the safety and feasibility of selective occlusion of the hepatic artery and portal vein (SOAP) for staged hepatectomy (SOAPS) in patients with hepatocellular carcinoma (HCC) METHODS: From December 2014 to August 2018, 9 patients with unresectable HCC were chosen to undergo SOAPS. SOAP without liver partition was performed in the first stage. The second stage was performed when future liver remnant (FLR) was equal to or bigger than 40% of the standard liver volume (SLV). The growth rate of FLR, perioperative outcomes, and survival data was recorded. RESULTS: In the first stage, all the 9 patients completed SOAP. Two cases received radiological interventional method and 7 cases received open operation. None of them developed liver failure and died following SOAP. After SOAP, FLR increased 145.0 ml (115.0 to 210 ml) and 37.1% (25.6 to 51.7%) on average. The average time interval between the two stages was 14.1 days (8 to 18 days). In the second stage, no in-hospital deaths occurred after SOAPS. One patient suffered from liver failure after SOAPS, and artificial liver support was adopted and his total bilirubin level returned to normal after postoperative day 35. The alpha-fetoprotein level of 8 patients reduced to normal within 2 months after SOAPS. Among 9 patients, 5 patients survived, 4 patients died of intrahepatic recurrence, lung metastasis, or bone metastasis. In the 5 survived cases, bone metastasis and intrahepatic recurrence were found in 1 patient, intrahepatic recurrence was found in another patient, and the remaining 3 patients were free of recurrence. The median disease-free survival time and overall survival time were 10.4 and 13.9 months, respectively. CONCLUSION: SOAP can facilitate rapid and sustained FLR hypertrophy, and SOAPS is safe and effective in patients with unresectable HCC.

Hypoxia Activates the PTHrP -MEF2C Pathway to Attenuate Hypertrophy in Mesenchymal Stem Cell Derived Cartilage.

Articular cartilage lacks an intrinsic repair capacity and due to the ability of mesenchymal stem cells (MSCs) to differentiate into chondrocytes, MSCs have been touted as a cellular source to regenerate damaged cartilage. However, a number of prevailing concerns for such a treatment remain. Generally, administration of MSCs into a cartilage defect results in poor regeneration of the damaged cartilage with the repaired cartilage consisting primarily of fibro-cartilage rather than hyaline cartilage. Methods that improve the chondrogenic potential of transplanted MSCs in vivo may be advantageous. In addition, the proclivity of MSC-derived cartilage to undergo hypertrophic differentiation or form bone in vivo also remains a clinical concern. If MSC-derived cartilage was to undergo hypertrophic differentiation in vivo, this would be deleterious in a clinical setting. This study focuses on establishing a mechanism of action by which hypoxia or low oxygen tension can be used to both enhance chondrogenesis and attenuate hypertrophic differentiation of both MSC and ATDC5 derived chondrocytes. Having elucidated a novel mechanism of action, the subsequent goals of this study were to develop an in vitro culture regime to mimic the beneficial effects of physiological low oxygen tension in a normoxic environment.

Metformin reduces fibrosis factors in insulin resistant and hypertrophied adipocyte via integrin/ERK, collagen VI, apoptosis, and necrosis reduction.

AIMS: Fibrosis as the hallmark of adipose tissue dysfunction which is associated with insulin resistance and type 2 diabetes, results from deposition of excess extra cellular matrix components like collagen and increased cell death. Here we investigated the effect of antidiabetic drug, Metformin, on the factors that play role in fibrosis such as; integrin/ERK pathway, collagen VI, MMP2, MMP9, apoptosis markers including DAPK1, DAPK3, DAP, SIVA, necrosis markers including RIPK1, RIPK3, and MLKL in insulin resistant and hypertrophied adipocytes. METHODS: 3T3-L1 adipocytes after differentiation to insulin resistant and hypertrophied cells, treated with Metformin, and the gene expression of aforementioned factors assayed by real time PCR. The protein expression of collagen VI and ERK assayed by western blotting. KEY FINDINGS: The expression of integrins changed from 0.5 to 6-fold in hypertrophied adipocyte versus adipocyte. Apoptosis and necrosis markers increased >1.5-fold in insulin resistant and hypertrophied adipocytes. Also ECM components and ERK activation increased >2-fold and 1.5-fold, respectively in insulin resistant and hypertrophied adipocytes. Metformin caused reduction of activity of integrin/ERK pathway in Metformin treated insulin resistant and hypertrophied adipocytes compared to untreated group. Metformin also reduced collagen VI in both gene and protein expression level, MMP2 and MMP9 in gene expression, and also the expression of apoptosis and necrosis gene. SIGNIFICANCE: Metformin with reduction of ECM component as collagen VI, MMP2 and MMP9, integrin/ERK pathway, necrosis markers as RIPK1, RIPK3 and MLKL, and apoptosis markers including DAP, DAPK1, DAPK3 and SIVA effects on fibrosis in insulin resistant and hypertrophied adipocytes in vitro.

Adiponectin for the treatment of diabetic nephropathy.

The metabolic burden caused by hyperglycemia can result in direct and immediate metabolic injuries, such as oxidative stress and tissue inflammation, in the kidney. Furthermore, chronic hyperglycemia can lead to substantial structural changes such as formation of advanced glycation end-products, glomerular and tubular hypertrophy, and tissue fibrosis. Glomerular hypertrophy renders podocytes vulnerable to increased glomerular filtration, leading to podocyte instability and loss. Thus, prevention of glomerular hypertrophy and attenuation of glomerular hyperfiltration may have therapeutic potential for diabetic nephropathy (DN). Adiponectin is an adipokine that improves insulin sensitivity in obesity-related metabolic disorders, including diabetes, but its efficacy is unknown. Moreover, the recently developed adiponectin receptor agonist, AdipoRon, shows therapeutic potential for DN. In this review, we focus on the role of glomerular hypertrophy in the pathogenesis of DN and discuss the role of adiponectin in its prevention.

Angiotensin-converting enzyme inhibitors attenuated advanced glycation end products-induced renal tubular hypertrophy via enhancing nitric oxide signaling.

Advanced glycation end products (AGE) and angiotensin II were closely correlated with the progression of diabetic nephopathy (DN). Nitric oxide (NO) is a protective mediator of renal tubular hypertrophy in DN. Here, we examined the molecular mechanisms of angiotensin-converting enzyme inhibitor (ACEI) and NO signaling responsible for diminishing AGE-induced renal tubular hypertrophy. In human renal proximal tubular cells, AGE decreased NO production, inducible NOS activity, guanosine 3',5'-cyclic monophosphate (cGMP) synthesis, and cGMP-dependent protein kinase (PKG) activation. All theses effects of AGE were reversed by treatment with ACEIs (captopril and enalapril), the NO donor S-nitroso-N-acetylpenicillamine (SNAP), and the PKG activator 8-para-chlorophenylthio-cGMPs (8-pCPT-cGMPs). In addition, AGE-enhanced activation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) were clearly reduced by captopril, enalapril, SNAP, and 8-pCPT-cGMPs. The abilities of ACEIs and NO/PKG activation to inhibit AGE-induced hypertrophic growth were verified by the observation that captopril, enalapril, SNAP, and 8-pCPT-cGMPs decreased protein levels of fibronectin, p21 Waf1/Cip1 , and receptor for AGE. The results of the present study suggest that ACEIs significantly reduced AGE-increased ERK/JNK/p38 MAPK activation and renal tubular hypertrophy partly through enhancement of the NO/PKG pathway.

Wnt16 attenuates osteoarthritis progression through a PCP/JNK-mTORC1-PTHrP cascade.

OBJECTIVES: Wnt16 is implicated in bone fracture and bone mass accrual both in animals and humans. However, its functional roles and molecular mechanism in chondrocyte differentiation and osteoarthritis (OA) pathophysiology remain largely undefined. In this study, we analysed its mechanistic association and functional relationship in OA progression in chondrocyte lineage. METHODS: The role of Wnt16 during skeletal development was examined by Col2a1-Wnt16 transgenic mice and Wnt16fl/fl;Col2a1-Cre (Wnt16-cKO) mice. OA progression was assessed by micro-CT analysis and Osteoarthritis Research Society International score after anterior cruciate ligament transection (ACLT) surgery with Wnt16 manipulation by adenovirus intra-articular injection. The molecular mechanism was investigated in vitro using 3D chondrocyte pellet culture and biochemical analyses. Histological analysis was performed in mouse joints and human cartilage specimens. RESULTS: Wnt16 overexpression in chondrocytes in mice significantly inhibited chondrocyte hypertrophy during skeletal development. Wnt16 deficiency exaggerated OA progression, whereas intra-articular injection of Ad-Wnt16 markedly attenuated ACLT-induced OA. Cellular and molecular analyses showed that, instead of ß-catenin and calcium pathways, Wnt16 activated the planar cell polarity (PCP) and JNK pathway by interacting mainly with AP2b1, and to a lesser extend Ror2 and CD146, and subsequently induced PTHrP expression through phosphor-Raptor mTORC1 pathway. CONCLUSIONS: Our findings indicate that Wnt16 activates PCP/JNK and crosstalks with mTORC1-PTHrP pathway to inhibit chondrocyte hypertrophy. Our preclinical study suggests that Wnt16 may be a potential therapeutic target for OA treatment.

Upregulation of C/EBPß and TSC2 by an HDAC inhibitor CG200745 protects heart from DOCA-induced hypertrophy.

Histone deacetylases (HDACs) are a vast family divided into four major classes: class I (1, 2, 3, and 8), class II (4, 5, 6, 7, 9 and 10), class III (sirtuin family) and class IV (HDAC11). HDAC inhibition attenuates cardiac hypertrophy through suppression of the mechanistic target of rapamycin complex1 (mTORC1) signaling. HDAC inhibitors upregulate the expression of tuberous sclerosis complex 2 (TSC2), an mTORC1 inhibitor. However, the molecular mechanism underlying HDAC inhibitor-mediated upregulation of TSC2 is unclear. We hypothesized that an HDAC inhibitor, CG200745 (CG), ameliorates cardiac hypertrophy through the inhibition of mTORC1 signaling by upregulating of the CCAAT/enhancer-binding protein-ß (C/EBP-ß)/TSC2 pathway. To establish a cardiac hypertrophy model, deoxycorticosterone acetate (DOCA, 40 mg/kg/wk) was subcutaneously injected for 4 weeks into Sprague-Dawley rats. All rats were unilaterally nephrectomized and had free access to drinking water containing 1% NaCl with or without CG of different concentrations. The expression level of TSC2 and C/EBP-ß was measured by quantitative real-time PCR (qRT-PCR) and western blot analysis. Acetylation of C/EBP-ß was analyzed by immunoprecipitation. The recruitment of C/EBP-ß and polymerase II (Pol II) on TSC2 promoter region was analyzed by chromatin immunoprecipitation (ChIP). CG treatment increased the expression of TSC2. In addition, CG treated rats showed an increased in the expression and acetylation of C/EBP-ß, owing to the increase in the recruitment of C/EBP-ß and Pol II at Tsc2 gene promoter. Thus, CG ameliorates cardiac hypertrophy through the inhibition of mTORC1 signaling via upregulation of the C/EBP-ß/TSC2 pathway in DOCA-induced hypertensive rats.

Icariside II attenuates cardiac remodeling via AMPKα2/mTORC1 in vivo and in vitro.

Icariside II (ICA II), a flavonoid derived from Epimediumbrevicormum Maxin in, has multiple biological activities in Chinese traditional medicine. Our study aimed to investigate the potential activity of ICA II against cardiac remodeling and the underlying mechanism. Mice received aorta banding (AB) or sham surgery, and then were randomly divided into ICA II or vehicle (veh) group for 6 weeks. After echocardiography and pressure-volume loop examination, hearts were harvested for histopathological analysis and molecular mechanism investigation. Additionally, neonatal rat cardiomyocytes (NRCM) were used for in vitro experiments. ICA II attenuated the systolic and diastolic cardiac dysfunction, and protected mouse heart from hypertrophy and fibrosis. The underlying mechanism might involve in the regulation of Akt, AMPKα and mTORC. In in vitro experiment, ICA II prevented phenylephrine (PE) induced NRCM hypertrophy by regulating AMPKα/mTORC pathway. This protective effect was disappeared after treatment with Compound C (CpC), an AMPKα inhibitor. Moreover, ICA II activated AMPK at baseline. ICAII was superior to resveratrol in activating AMPKα and similar to AICAR. ICA II protected against cardiac remodeling and NRCM hypertrophy by regulating AMPK/mTORC pathway. ICA II may be a candidate for the treatment of malignant cardiac remodeling.

Rapamycin attenuates pathological hypertrophy caused by an absence of trabecular formation.

Cardiac trabeculae are mesh-like muscular structures within ventricular walls. Subtle perturbations in trabeculation are associated with many congenital heart diseases (CHDs), and complete failure to form trabeculae leads to embryonic lethality. Despite the severe consequence of an absence of trabecular formation, the exact function of trabeculae remains unclear. Since ErbB2 signaling plays a direct and essential role in trabecular initiation, in this study, we utilized the erbb2 zebrafish mutant as a model to address the function of trabeculae in the heart. Intriguingly, we found that the trabeculae-deficient erbb2 mutant develops a hypertrophic-like (HL) phenotype that can be suppressed by inhibition of Target of Rapamycin (TOR) signaling in a similar fashion to adult mammalian hearts subjected to mechanical overload. Further, cell transplantation experiments demonstrated that erbb2 mutant cells in an otherwise wildtype heart did not undergo hypertrophy, indicating that erbb2 mutant HL phenotypes are due to a loss of trabeculae. Together, we propose that trabeculae serve to enhance contractility and that defects in this process lead to wall-stress induced hypertrophic remodeling.