Anti-adipogenic effects of KD025 (SLx-2119), a ROCK2-specific inhibitor, in 3T3-L1 cells

Effect of DHCR7 on adipocyte differentiation in goats

Cholesterol is regarded as a signaling molecule in regulating the metabolism and function of fat cells, in which 7-Dehydrocholesterol reductase (DHCR7) is a key enzyme that catalyzes the conversion of 7-dehydrocholesterol to cholesterol, however, the exact function of DHCR7 in goat adipocytes remains unknown. Here, the effect of DHCR7 on the formation of subcutaneous and intramuscular fat in goats was investigated in vitro, and the result indicated that the mRNA level of DHCR7 showed a gradual downward trend in subcutaneous adipogenesis, but an opposite trend in intramuscular adipogenesis. In the process of subcutaneous preadipocytes differentiation, overexpression of DHCR7 inhibited the expression of adipocytes differentiation marker genes (CEBP/α, CEBP/β, SREBP1 and AP2), lipid metabolism-related genes (AGPAT6, FASN, SCD1 and LPL), and the lipid accumulation. However, in intramuscular preadipocyte differentiation, DHCR7 overexpression showed a promoting effect on adipocyte differentiation marker genes (CEBP/α, CEBP/β, PPARγ and SREBP1) and lipid metabolism-related genes (GPAM, AGPAT6, DGAT1 and SCD1) expression, and on lipid accumulation. In summary, our work demonstrated that DHCR7 played an important role in regulating adipogenic differentiation and lipid metabolism in preadipocytes in goats, which is of great significance for uncovering the underlying molecular mechanism of adipocyte differentiation and improving goat meat quality.

Unraveling the rationale and conducting a comprehensive assessment of KD025 (Belumosudil) as a candidate drug for inhibiting adipogenic differentiation-a systematic review

Rho-associated kinases (ROCKs) are crucial during the adipocyte differentiation process. KD025 (Belumosudil) is a newly developed inhibitor that selectively targets ROCK2. It has exhibited consistent efficacy in impeding adipogenesis across a spectrum of in vitro models of adipogenic differentiation. Given the novelty of this treatment, a comprehensive systematic review has not been conducted yet. This systematic review aims to fill this knowledge void by providing readers with an extensive examination of the rationale behind KD025 and its impacts on adipogenesis. Preclinical evidence was gathered owing to the absence of clinical trials. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed, and the study's quality was assessed using the Joanna Briggs Institute (JBI) Checklist Critical Appraisal Tool for Systematic Reviews. In various in vitro models, such as 3T3-L1 cells, human orbital fibroblasts, and human adipose-derived stem cells, KD025 demonstrated potent anti-adipogenic actions. At a molecular level, KD025 had significant effects, including decreasing fibronectin (Fn) expression, inhibiting ROCK2 and CK2 activity, suppressing lipid droplet formation, and reducing the expression of proadipogenic genes peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα). Additionally, KD025 resulted in the suppression of fatty acid-binding protein 4 (FABP4 or AP2) expression, a decrease in sterol regulatory element binding protein 1c (SREBP-1c) and Glut-4 expression. Emphasis must be placed on the fact that while KD025 shows potential in preclinical studies and experimental models, extensive research is crucial to assess its efficacy, safety, and potential therapeutic applications thoroughly and directly in human subjects.

The Effect of Rho Kinase Inhibitors on In Vitro Human Orbital Preadipocytes

PURPOSE

To identify the effects of Rho Kinase (ROCK) inhibitor medications on human orbital adipogenesis, fibroblast proliferation, and fibrosis.

METHODS

Orbital adipose tissue was obtained from patients with Graves' ophthalmopathy (GO) as well as controls (non-GO or normal) after informed consent was done. These tissue samples were cultured and adipogenesis was initiated. Levels of Rho Kinase as well as cellular mediators of orbital inflammation and fibrosis. The same cultures and measurements were then repeated with the use of a ROCK inhibitor (KD025-ROCK2) to assess for changes in adipogenesis as well as markers associated with inflammation and fibrosis.

RESULTS

Rho Kinase levels in GO tissue were more highly expressed than in controls. These levels were suppressed with the use of the ROCK inhibitor KD025. There was a dose-dependent reduction in differentiation of orbital adipocytes with the use of KD025. KD025 reduced the levels of fibrosis-related gene expression. Finally, there was a significant reduction of transforming growth factor beta mediated phosphorylation signaling pathways in the KD025-treated GO tissue.

CONCLUSION

This study shows that the ROCK inhibitor, KD025, helps to reduce the expression of ROCK in GO tissue along with reducing orbital adipocyte differentiation as well as cell mediators involved in fibrosis that occurs in GO.

Selectivity matters: selective ROCK2 inhibitor ameliorates established liver fibrosis via targeting inflammation, fibrosis, and metabolism

The pathogenesis of hepatic fibrosis is driven by dysregulated metabolism precipitated by chronic inflammation. Rho-associated coiled-coil-containing protein kinases (ROCKs) have been implicated in these processes, however the ability of selective ROCK2 inhibition to target simultaneously profibrotic, pro-inflammatory and metabolic pathways remains undocumented. Here we show that therapeutic administration of GV101, a selective ROCK2 inhibitor with more than 1000-fold selectivity over ROCK1, attenuates established liver fibrosis induced by thioacetamide (TAA) in combination with high-fat diet in mice. GV101 treatment significantly reduces collagen levels in liver, associated with downregulation of pCofilin, pSTAT3, pAkt, while pSTAT5 and pAMPK levels are increased in tissues of treated mice. In vitro, GV101 inhibits profibrogenic markers expression in fibroblasts, adipogenesis in primary adipocytes and TLR-induced cytokine secretion in innate immune cells via targeting of Akt-mTOR-S6K signaling axis, further uncovering the ROCK2-specific complex mechanism of action and therapeutic potential of highly selective ROCK2 inhibitors in liver fibrosis.

In silico screening-based discovery of benzamide derivatives as inhibitors of Rho-associated kinase-1 (ROCK1)

As a pivotal node in modulating various cell behaviors, Rho-associated kinase-1 (ROCK1) has attracted significant attention as a promising therapeutic target in a variety of diseases. Benzamide has been widely reported as a ROCK1 inhibitors in recent years. To better understand its pharmacological properties and to explore its potential inhibitors, a series of ROCK1 inhibitors derived from N-methyl-4-(4-pyrazolidinyl) benzamides (MPBs) were investigated by using three-dimensional quantitative structure-activity relationship (3D-QSAR) models, pharmacophore models, molecular docking, and molecular dynamics (MD) simulation. The comparative Molecular Field Analysis (CoMFA) model (q2 = 0.616, R2 = 0.972, ONC = 4, and r2pred = 0.983) and the best Comparative Molecular Similarity Indices Analysis (CoMSIA) model (q2= 0.740, R2 = 0.982, ONC = 6, and r2pred = 0.824) exhibited reliable predictability with satisfactory validation parameters. In the subsequent virtual screening, VS03 and VS05 were identified to have superior predicted activities and higher docking scores, meanwhile they demonstrated to be reasonably stable in the binding pocket through MD simulations. These results provide a significant theoretical direction for the rational design and development of novel ROCK1 inhibitors.Communicated by Ramaswamy H. Sarma.

Simultaneous Effects of a Selective EP2 Agonist, Omidenepag, and a Rho-Associated Coiled-Coil Containing Protein Kinase Inhibitor, Ripasudil, on Human Orbital Fibroblasts

Purpose: To assess the combined effects of omidenepag (OMD), a selective EP2 agonist, and ripasudil (Rip), an inhibitor of rho-associated coiled-coil containing protein kinases, on the human orbital adipose tissue, two-dimensional (2D) or three-dimensional (3D) cultures of human orbital fibroblasts (HOFs) were employed. Methods: Cellular metabolic functions (2D), physical (3D), lipid staining (3D), and quantitative polymerase chain reaction for adipogenesis-related genes, PPARγ and AP2, and extracellular matrix (ECM) molecules, including collagen (COL)1, 4, and 6, and fibronectin (FN) (3D) were evaluated in the presence of OMD (100 nM) and/or Rip (10 μM). Results: Real-time metabolic analyses revealed that the adipogenic differentiation (DIF+) with OMD significantly shifted an energetic state toward energetic, whereas DIF+ with Rip significantly shifted that toward quiescent. In the case of both drugs upon DIF+, the metabolic effect of OMD was predominant. DIF+ induced enlargement and stiffed 3D spheroid with increased lipid staining and mRNA expression of adipogenesis-related genes, COL4 and COL6, and decreased the expression of COL1. In the presence of OMD and/or Rip to DIF+, (1) the sizes were further increased by Rip and the stiffness was significantly decreased by OMD or Rip and (2) COL4 or AP2 expression was substantially increased by OMD or Rip, respectively. Conclusion: The results presented herein indicate that the metabolic effects of OMD and Rip exerted opposing effects and the effects of OMD toward Ap2 and ECM expressions were distinct from those of Rip, but the effects of OMD toward the physical aspects and adipogenesis of the 3D cultured HOFs were similar to the effects of Rip.

ROCK1 regulates insulin secretion from β-cells

OBJECTIVE

The endocrine pancreatic β-cells play a pivotal role in maintaining whole-body glucose homeostasis and its dysregulation is a consistent feature in all forms of diabetes. However, knowledge of intracellular regulators that modulate β-cell function remains incomplete. We investigated the physiological role of ROCK1 in the regulation of insulin secretion and glucose homeostasis.

METHODS

Mice lacking ROCK1 in pancreatic β-cells (RIP-Cre; ROCK1^loxP/loxP, β-ROCK1^-/-) were studied. Glucose and insulin tolerance tests as well as glucose-stimulated insulin secretion (GSIS) were measured. An insulin secretion response to a direct glucose or pyruvate or pyruvate kinase (PK) activator stimulation in isolated islets from β-ROCK1^-/- mice or β-cell lines with knockdown of ROCK1 was also evaluated. A proximity ligation assay was performed to determine the physical interactions between PK and ROCK1.

RESULTS

Mice with a deficiency of ROCK1 in pancreatic β-cells exhibited significantly increased blood glucose levels and reduced serum insulin without changes in body weight. Interestingly, β-ROCK1^-/- mice displayed a progressive impairment of glucose tolerance while maintaining insulin sensitivity mostly due to impaired GSIS. Consistently, GSIS markedly decreased in ROCK1-deficient islets and ROCK1 knockdown INS-1 cells. Concurrently, ROCK1 blockade led to a significant decrease in intracellular calcium and ATP levels and oxygen consumption rates in isolated islets and INS-1 cells. Treatment of ROCK1-deficient islets or ROCK1 knockdown β-cells either with pyruvate or a PK activator rescued the impaired GSIS. Mechanistically, we observed that glucose stimulation in β-cells greatly enhanced ROCK1 binding to PK.

CONCLUSIONS

Our findings demonstrate that β-cell ROCK1 is essential for glucose-stimulated insulin secretion and for glucose homeostasis and that ROCK1 acts as an upstream regulator of glycolytic pyruvate kinase signaling.

Addition of ROCK Inhibitors Alleviates Prostaglandin-Induced Inhibition of Adipogenesis in 3T3L-1 Spheroids

To elucidate the additive effects of the ROCK inhibitors (ROCK-i), ripasudil (Rip) and Y27632 on bimatoprost acid (BIM-A), a prostaglandin analog (PG), on adipose tissue, two- and three-dimensional (2D or 3D) cultures of 3T3-L1 cells, the most well characterized cells in the field of lipid research, were used. The cells were subjected to a variety of analyses including lipid staining, real-time cellular metabolic analysis, the mRNA expressions of genes related to adipogenesis and extracellular matrices (ECMs) as well as the sizes and physical properties of the 3D spheroids by a micro-squeezer. BIM-A induced strong inhibitory effects on most of the adipogenesis-related changes in the 2D and 3D cultured 3T3-L1 cells, including (1) the enlargement and softening of the 3D spheroids, (2) a dramatic enhancement in lipid staining and the expression of adipogenesis-related genes, and (3) a decrease in mitochondrial and glycolytic metabolic function. By adding ROCK-i to the BIM-A, most of these BIM-A-induced effects were cancelled. The collective findings reported herein suggest that ROCK-i eliminated the PG-induced suppression of adipogenesis in the 3T3-L1 cells, accompanied by the formation of enlarged 3D spheroids. Such effects of adding ROCK-i to a PG in preadipocytes on cellular properties appear to be associated with the suppression of PG-induced adverse effects, and provide additional insight into our understanding of lipid-related research.

Brimonidine Modulates the ROCK1 Signaling Effects on Adipogenic Differentiation in 2D and 3D 3T3-L1 Cells

The additive effects of an α2-adrenergic agonist, brimonidine (BRI), on the pan-ROCK inhibitor (ROCK-i), ripasudil (Rip), and the ROCK2-I, KD025, on adipogenic differentiation (DIF+) were examined using two- or three-dimension (2D or 3D) cultures of 3T3-L1 cells. The following analyses were carried out: (1) lipid staining (2D and 3D), (2) real-time measurements of cellular metabolism (2D), (3) mRNA expression of DIF+ related genes and extracellular matrix molecules (ECMs) including collagen (Col)-1, -4, and -6, and fibronectin (Fn), and (4) the sizes and physical properties of the 3D spheroids. The findings indicate that DIF+ induced (1) a substantial enhancement in lipid staining and enhanced expression of the Pparγ and Fabp4 genes, (2) significantly larger and softer 3D spheroids, and (3) down-regulation of Col1 and Fn and up-regulation of Col4 and Col6 genes. Treatment with Rip alone caused a significant enhancement in adipogenesis of both the 2D and 3D cultured 3T3-L1 cells and in the physical properties of the 3D spheroids; these effects were substantially inhibited by BRI, and the effects induced by BRI or KD025 were not insignificant. These collective findings indicate that the addition of BRI inhibited the Rip-induced enhancement of DIF+ in 3T3-L1 cells, presumably by modulating ROCK1 signaling.

Activity of ROCKII not ROCKI promotes pulmonary metastasis of melanoma cells via modulating Smad2/3-MMP9 and FAK-Src-VEGF signalling

Rho-associated coiled-coil kinase (ROCK) inhibition decreases tumourogenic growth, proliferation and angiogenesis. Multifaceted evidences are there about the role of ROCK in cancer progression, but isoform specific analysis in secondary pulmonary melanoma is still unaddressed. This study explored the operating function of ROCK in the metastasis of B16F10 mice melanoma cell line. Inhibition by KD-025 indicated dual wielding role of ROCKII as it is associated with the regulation of MMP9 activity responsible for extra-cellular matrix (ECM) degradation as well as angiogenic invasion as an effect of Src-FAK-STAT3 interaction dependent VEGF switching. We found the assisting role of ROCKII, not ROCKI in nuclear localization of Smads that effectively increased MMP9 expression and activity (p < 0.01). This cleaved the protein components of ECM thereby played a crucial role in tissue remodeling at secondary site during establishment of metastatic tumour. ROCKII phosphorylation at Ser¹³⁶⁶ as an activation of the same was imprinted essential for oncogenic molecular bagatelle leading to histo-architectural change of pulmonary tissue with extracellular matrix degradation as a consequence of invasion. Direct correlation of pROCKIISer¹³⁶⁶ with MMP9 as well as VEGF expression in vivo studies cue to demonstrate the importance of pROCKIISer¹³⁶⁶ inhibition in the context of angiogenesis, and metastasis suggesting ROCKII signaling as a possible target for the treatment of secondary lung cancer specially in metastatic melanoma.

Insight Into Rho Kinase Isoforms in Obesity and Energy Homeostasis

Obesity and associated complications increasingly jeopardize global health and contribute to the rapidly rising prevalence of type 2 diabetes mellitus and obesity-related diseases. Developing novel methods for the prevention and treatment of excess body adipose tissue expansion can make a significant contribution to public health. Rho kinase is a Rho-associated coiled-coil-containing protein kinase (Rho kinase or ROCK). The ROCK family including ROCK1 and ROCK2 has recently emerged as a potential therapeutic target for the treatment of metabolic disorders. Up-regulated ROCK activity has been involved in the pathogenesis of all aspects of metabolic syndrome including obesity, insulin resistance, dyslipidemia and hypertension. The RhoA/ROCK-mediated actin cytoskeleton dynamics have been implicated in both white and beige adipogenesis. Studies using ROCK pan-inhibitors in animal models of obesity, diabetes, and associated complications have demonstrated beneficial outcomes. Studies via genetically modified animal models further established isoform-specific roles of ROCK in the pathogenesis of metabolic disorders including obesity. However, most reported studies have been focused on ROCK1 activity during the past decade. Due to the progress in developing ROCK2-selective inhibitors in recent years, a growing body of evidence indicates more attention should be devoted towards understanding ROCK2 isoform function in metabolism. Hence, studying individual ROCK isoforms to reveal their specific roles and principal mechanisms in white and beige adipogenesis, insulin sensitivity, energy balancing regulation, and obesity development will facilitate significant breakthroughs for systemic treatment with isoform-selective inhibitors. In this review, we give an overview of ROCK functions in the pathogenesis of obesity and insulin resistance with a particular focus on the current understanding of ROCK isoform signaling in white and beige adipogenesis, obesity and thermogenesis in adipose tissue and other major metabolic organs involved in energy homeostasis regulation.

TGF-Beta Induced Key Genes of Osteogenic and Adipogenic Differentiation in Human Mesenchymal Stem Cells and MiRNA-mRNA Regulatory Networks

Background: The clinical efficacy of osteoporosis therapy is unsatisfactory. However, there is currently no gold standard for the treatment of osteoporosis. Recent studies have indicated that a switch from osteogenic to adipogenic differentiation in human bone marrow mesenchymal stem cells (hMSCs) induces osteoporosis. This study aimed to provide a more comprehensive understanding of the biological mechanisms involved in this process and to identify key genes involved in osteogenic and adipogenic differentiation in hMSCs to provide new insights for the prevention and treatment of osteoporosis.

Methods: Microarray and bioinformatics approaches were used to identify the differentially expressed genes (DEGs) involved in osteogenic and adipogenic differentiation, and the biological functions and pathways of these genes were analyzed. Hub genes were identified, and the miRNA–mRNA interaction networks of these hub genes were constructed.

Results: In an optimized microenvironment, transforming growth factor-beta (TGF-beta) could promote osteogenic differentiation and inhibit adipogenic differentiation of hMSCs. According to our study, 98 upregulated genes involved in osteogenic differentiation and 66 downregulated genes involved in adipogenic differentiation were identified, and associated biological functions and pathways were analyzed. Based on the protein–protein interaction (PPI) networks, the hub genes of the upregulated genes (CTGF, IGF1, BMP2, MMP13, TGFB3, MMP3, and SERPINE1) and the hub genes of the downregulated genes (PPARG, TIMP3, ANXA1, ADAMTS5, AGTR1, CXCL12, and CEBPA) were identified, and statistical analysis revealed significant differences. In addition, 36 miRNAs derived from the upregulated hub genes were screened, as were 17 miRNAs derived from the downregulated hub genes. Hub miRNAs (hsa-miR-27a/b-3p, hsa-miR-128-3p, hsa-miR-1-3p, hsa-miR-98-5p, and hsa-miR-130b-3p) coregulated both osteogenic and adipogenic differentiation factors.

Conclusion: The upregulated hub genes identified are potential targets for osteogenic differentiation in hMSCs, whereas the downregulated hub genes are potential targets for adipogenic differentiation. These hub genes and miRNAs play important roles in adipogenesis and osteogenesis of hMSCs. They may be related to the prevention and treatment not only of osteoporosis but also of obesity.

ROCK inhibitors modulate the physical properties and adipogenesis of 3D spheroids of human orbital fibroblasts in different manners

To elucidate the pharmacological effects of Rho-associated coiled-coil containing protein kinase inhibitors (ROCK-is), ripasudil (Rip), Y27632, and KD025, on human orbital fatty tissue, the human orbital fibroblasts (HOFs) were three-dimensional (3D) cultured for 12 days. The effects of ROCK-is on the physical properties of the 3D-cultured HOF spheroids, including their sizes and physical stiffness, their adipogenesis by lipid staining, and the mRNA expression of adipogenesis-related genes, PPARγ and AP2, and extracellular matrix (ECM) including collagen (COL) 1, 4, and 6, and fibronectin were analyzed. A significant increase in the sizes, physical stiffness, lipid staining, and mRNA expression of adipogenesis-related genes, COL4 and COL6, and a decrease in COL1 expression were observed with adipogenesis (DIF+). In the presence of ROCK-is, such DIF+-induced effects were differently modulated as follows: (1) the sizes were not affected or significantly enhanced by Rip, Y27632, or KD025, (2) the physical stiffness was significantly decreased in Rip and Y27632, but was substantially increased in KD025, (3) the lipid staining was further enhanced or significantly suppressed by Rip, Y27632, or KD025, and both PPARγ and AP2 expression were significantly downregulated or upregulated by KD025 or Rip, and (4) Rip upregulated the expression of COL4, Y27632 upregulated the expression of COL1, COL4, and COL6, and KD025 upregulated the expression of COL1 and COL4. This study indicates that ROCK-is significantly and differently modulate physical properties of the 3D HOF spheroids as well as their adipogenesis.

Genome Profiling of H3k4me3 Histone Modification in Human Adipose Tissue during Obesity and Insulin Resistance

Background: Adipose tissue (AT) dysfunction is involved in obesity-related comorbidities. Epigenetic alterations have been recently associated with AT deterioration in obesity conditions. In this work, we profiled the H3K4me3 histone mark in human AT, with special emphasis on the changes in the pattern of histone modification in obesity and insulin resistance (IR). Visceral AT (VAT) was collected and subjected to chromatin immunoprecipitation (ChIP) using anti-H3K4me3 antibody and then sequenced to obtain the H3K4me3 genome profile. Results: We found that most of the H3K4me3 enriched regions were located in gene promoters of pathways related to AT biology and function. H3K4me3 enrichment at gene promoters was strongly related to higher mRNA levels. Differentially expressed genes in AT of patients classified as non-obese, obese with low IR, and obese with high IR could be regulated by differentially enriched H3K4me3; these genes encoded for pathways that could in part explain AT functioning during obesity and insulin resistance (e.g., extracellular matrix organization, PPARG signaling or inflammation). Conclusions: In conclusion, we emphasize the importance of the epigenetic mark H3K4me3 in VAT dysfunction in obesity and IR. The understanding of such mechanisms could give rise to the development of new epigenetic-based pharmacological strategies to ameliorate obesity-related comorbidities.

Addition of ROCK inhibitors to prostaglandin derivative (PG) synergistically affects adipogenesis of the 3D spheroids of human orbital fibroblasts (HOFs)

To study the additive effects of Rho-associated coiled-coil containing protein kinase inhibitors, ripasudil (Rip) to bimatoprost acid (BIM-A) on orbital adipose tissue, three-dimensional (3D) cultures of human orbital fibroblasts (HOFs) were prepared and the physical properties including the 3D spheroid size and stiffness, lipid staining by BODIPY and the mRNA expression of adipogenesis-related genes, PPARγ and AP2, and extracellular matrix (ECM) including collagen (COL)1, 4 and 6, and fibronectin (FN) were analyzed. Adipogenesis (DIF+) induced (1) enlargement and increasing stiffness of the 3D HOFs spheroid, (2) increased lipid staining, the expression of adipogenesis-related gene expressions, and (3) the down-regulation of COL1 and FN and up-regulation of COL4 and COL6. In the presence of BIM-A, (1) such DIF+-induced changes in 3D spheroid size and stiffness were significantly inhibited or enhanced, respectively, (2) the lipid staining and its related gene expressions were significantly down-regulated, and (3) the expression of COL1 and COL6 were up-regulated. By the addition of Rip to BIM-A, the above BIM-A-induced effects were all inhibited, except for the up-regulation of COL6 and FN expression, that is, enlarging and decreasing stiffness, enhancement of lipid staining and its related gene expression, and down-regulation of COL1 expression. Our present study indicates that Rip significantly suppressed BIM-A-induced effects toward 3D HOFs spheroids.

ROCK2-Specific Inhibitor KD025 Suppresses Adipocyte Differentiation by Inhibiting Casein Kinase 2

KD025, a ROCK2 isoform-specific inhibitor, has an anti-adipogenic activity which is not mediated by ROCK2 inhibition. To identify the target, we searched binding targets of KD025 by using the KINOMEscanTM screening platform, and we identified casein kinase 2 (CK2) as a novel target. KD025 showed comparable binding affinity to CK2α (Kd = 128 nM). By contrast, CK2 inhibitor CX-4945 and ROCK inhibitor fasudil did not show such cross-reactivity. In addition, KD025 effectively inhibited CK2 at a nanomolar concentration (IC50 = 50 nM). We examined if the inhibitory effect of KD025 on adipocyte differentiation is through the inhibition of CK2. Both CX-4945 and KD025 suppressed the generation of lipid droplets and the expression of proadipogenic genes Pparg and Cebpa in 3T3-L1 cells during adipocyte differentiation. Fasudil exerted no significant effect on the quantity of lipid droplets, but another ROCK inhibitor Y-27632 increased the expression of Pparg and Cebpa. Both CX-4945 and KD025 acted specifically in the middle stage (days 1-3) but were ineffective when treated at days 0-1 or the late stages, indicating that CX-4945 and KD025 may regulate the same target, CK2. The mRNA and protein levels of CK2α and CK2β generally decreased in 3T3-L1 cells at day 2 but recovered thereafter. Other well-known CK2 inhibitors DMAT and quinalizarin inhibited effectively the differentiation of 3T3-L1 cells. Taken together, the results of this study confirmed that KD025 inhibits ROCK2 and CK2, and that the inhibitory effect on adipocyte differentiation is through the inhibition of CK2.

Simultaneous Use of ROCK Inhibitors and EP2 Agonists Induces Unexpected Effects on Adipogenesis and the Physical Properties of 3T3-L1 Preadipocytes

To elucidate the additive effects of an EP2 agonist, omidenepag (OMD) or butaprost (Buta) on the Rho-associated coiled-coil-containing protein kinase (ROCK) inhibitor, ripasudil (Rip) on adipose tissue, two- or three-dimension (2D or 3D) cultures of 3T3-L1 cells were analyzed by lipid staining, the mRNA expression of adipogenesis-related genes, extracellular matrix (ECM) molecules including collagen (Col) -1, -4 and -6, and fibronectin (Fn), and the sizes and physical properties of 3D organoids, as measured by a micro-squeezer. The results indicate that adipogenesis induced (1) an enlargement of the 3D organoids; (2) a substantial enhancement in lipid staining as well as the expression of the Pparγ, Ap2 and Leptin genes; (3) a significant softening of the 3D organoids, the effects of which were all enhanced by Rip except for Pparγ expression; and (4) a significant downregulation in Col1 and Fn, and a significant upregulation in Col4, Col6, the effects of which were unchanged by Rip. When adding the EP2 agonist to Rip, (1) the sizes of the 3D organoids were reduced substantially; (2) lipid staining was increased (OMD), or decreased (Buta); (3) the stiffness of the 3D organoids was substantially increased in Buta; (4-1) the expression of Pparγ was suppressed (2D, OMD) or increased (2D, Buta), and the expressions of Ap2 were downregulated (2D, 3D) and Leptin was increased (2D) or decreased (3D), (4-2) all the expressions of four ECM molecules were upregulated in 2D (2D), and in 3D, the expression of Col1, Col4 was upregulated. The collective findings reported herein indicate that the addition of an EP2 agonist, OMD or Buta significantly but differently modulate the Rip-induced effects on adipogenesis and the physical properties of 2D and 3D cultured 3T3-L1 cells.

ROCK inhibitors enhance the production of large lipid-enriched 3D organoids of 3T3-L1 cells

Since the recent discovery of prostaglandin-associated peri-orbitopathy, a great deal of interest has developed concerning the side effects of anti-glaucoma medications toward periocular fatty tissue, especially their adipogenesis. Two- or three-dimension (2D or 3D) cultures of the 3T3-L1 cells were employed to elucidate the effects of the Rho-associated coiled-coil containing protein kinase inhibitor (ROCK-i) the anti-glaucoma drug, Ripasudil, and other ROCK-i, such as Y27632 on adipogenesis. Ultrastructure by electron microscopy and physical stiffness measurements by a micro-squeezer demonstrated the 3D organoids had essentially matured during the 7-day culture. The effects of ROCK-i on 3D organoid sizes, lipid staining, the mRNA expression of adipogenesis related genes, Pparγ, Cebpa and Leptin, and extracellular matrix (ECM) including collagen (COL) 1, 4 and 6, and fibronectin, and physical stiffness were then conducted. Upon adipogenesis, the sizes, lipid staining and mRNA expressions of adipogenesis related genes, Col 4 and Col 6 were dramatically increased, and were further enhanced by ROCK-i. Micro-squeezer analysis demonstrated that adipogenesis resulted in a marked less stiffed 3D organoid and this was further enhanced by ROCK-i. Our present study indicates that ROCK-i significantly enhanced the production of large lipid-enriched 3T3-L1 3D organoids.

Prostaglandin F2α and EP2 agonists, and a ROCK inhibitor modulate the formation of 3D organoids of Grave's orbitopathy related human orbital fibroblasts

3D organoid cultures were used to elucidate the periocular effects of several anti-glaucoma drugs including a prostaglandin F2α analogue (bimatoprost acid; BIM-A), EP2 agonist (omidenepag; OMD) or a Rho-associated coiled-coil containing protein kinase (ROCK) inhibitor (ripasudil; Rip) on Grave's orbitopathy (GO) related orbital fatty tissue. 3D organoids were prepared from GO related human orbital fibroblasts (GHOFs) obtained from patients with GO. The effects of either 100 nM BIM-A, 100 nM OMD or 10 μM Rip on the 3D GHOFs organoids were examined with respect to organoid size, physical properties by a micro-squeezer, and the mRNA expression of extracellular matrix (ECM) proteins including collagen (COL) 1, COL 4, COL 6, and fibronectin (FN), ECM regulatory genes including lysyl oxidase (LOX), Connective Tissue Growth Factor (CTGF) and inflammatory cytokines including interleukin-1β (IL1β) and interleukin-6 (IL6). The size of the 3D GHOFs organoids decreased substantially in the presence of BIM-A, but also increased substantially in the presence of the others (OMD or Rip). The physical stiffness of the 3D GHOFs organoids was significantly decreased by Rip. BIM-A caused significantly the down-regulation of three ECM genes, Col 1, Col 6 and Fn, and two ECM regulatory genes and the up-regulation of IL6. In the presence of OMD, two ECM genes, Col 1 and Fn, and LOX were significantly down-regulated but IL1β and IL6 were significantly up-regulated. In the case of Rip, Col 1, FN and CTGF were significant down-regulated. Our present findings indicate that anti-glaucoma drugs modulate the structures and physical properties 3D GHOFs organoids in different manners by modifying the gene expressions of ECM, ECM regulatory factors and inflammatory cytokines. The results indicate that the benefits and demerits of anti-glaucoma medications need to be scrutinized carefully, in cases of patients with GO.

Role of Adiponectin and Brain Derived Neurotrophic Factor in Metabolic Regulation Involved in Adiposity and Body Fat Browning

Obesity, characterized by excessive fat mass, has been emerging as a major global epidemic and contributes to the increased risk of morbidity around the world. Thus, the necessity to find effective therapy and specific regulatory mechanisms is increasing for controlling obesity. Lately, many researchers have been interested in the linkage between obesity and adipokines/myokines, particularly adiponectin and brain-derived neurotrophic factor (BDNF). However, the role of adiponectin and BDNF in adiposity has not been clearly defined yet. We examined the association of adiposity with adiponectin and BDNF through human study (observational study) with Korean women and in vitro experiments. In the human study, we found a negative relationship between adiposity and circulating adiponectins but irregular patterns in the relationship between adiposity and circulating BDNFs. In the in vitro study using 3T3-L1 adipocytes, adiponectin treatment strongly promoted adipocyte differentiation and the fat browning process, whereas BDNF treatment attenuated adipocyte differentiation and the fat browning process in differentiated adipocytes. Our results demonstrate that adiponectin and BDNF play an important role in regulating fat mass and the expression of fat-browning markers in different ways, and also suggest that circulating adiponectin may be used as an important monitoring index for obesity status.

KD025 Shifts Pulmonary Endothelial Cell Bioenergetics and Decreases Baseline Lung Permeability

KD025 is a ROCK2 inhibitor currently being tested in clinical trials for the treatment of fibrotic lung diseases. The therapeutic effects of KD025 are partly due to its inhibition of profibrotic pathways and fat metabolism. However, whether KD025 affects pulmonary microvascular endothelial cell (PMVEC) function is unknown, despite evidence that alveolar-capillary membrane disruption constitutes major causes of death in fibrotic lung diseases. We hypothesized that KD025 regulates PMVEC metabolism, pH, migration, and survival, a series of interrelated functional characteristics that determine pulmonary barrier integrity. We used PMVECs isolated from Sprague Dawley rats. KD025 dose-dependently decreased lactate production and glucose consumption. The inhibitory effect of KD025 was more potent compared with other metabolic modifiers, including 2-deoxy-glucose, extracellular acidosis, dichloroacetate, and remogliflozin. Interestingly, KD025 increased oxidative phosphorylation, whereas 2-deoxy-glucose did not. KD025 also decreased intracellular pH and induced a compensatory increase in anion exchanger 2. KD025 inhibited PMVEC migration, but fasudil (nonspecific ROCK inhibitor) did not. We tested endothelial permeability in vivo using Evans Blue dye in the bleomycin pulmonary fibrosis model. Baseline permeability was decreased in KD025-treated animals independent of bleomycin treatment. Under hypoxia, KD025 increased PMVEC necrosis as indicated by increased lactate dehydrogenase release and propidium iodide uptake and decreased ATP; it did not affect Annexin V binding. ROCK2 knockdown had no effect on PMVEC metabolism, pH, and migration, but it increased nonapoptotic caspase-3 activity. Together, we report that KD025 promotes oxidative phosphorylation; decreases glycolysis, intracellular pH, and migration; and strengthens pulmonary barrier integrity in a ROCK2-independent manner.

Inhibition of ROCK2 alleviates renal fibrosis and the metabolic disorders in the proximal tubular epithelial cells

Non-specific inhibition of Rho-associated kinases (ROCKs) alleviated renal fibrosis in the unilateral ureteral obstruction (UUO) model, while genetic deletion of ROCK1 did not affect renal pathology in mice. Thus, whether ROCK2 plays a role in renal tubulointerstitial fibrosis needs to be clarified. In the present study, a selective inhibitor against ROCK2 or genetic approach was used to investigate the role of ROCK2 in renal tubulointerstitial fibrosis. In the fibrotic kidneys of chronic kidney diseases (CKDs) patients, we observed an enhanced expression of ROCK2 with a positive correlation with interstitial fibrosis. In mice, the ROCK2 protein level was time-dependently increased in the UUO model. By treating CKD animals with KD025 at the dosage of 50 mg/kg/day via intraperitoneal injection, the renal fibrosis shown by Masson's trichrome staining was significantly alleviated along with the reduced expression of fibrotic genes. In vitro, inhibiting ROCK2 by KD025 or ROCK2 knockdown/knockout significantly blunted the pro-fibrotic response in transforming growth factor-β1 (TGF-β1)-stimulated mouse renal proximal tubular epithelial cells (mPTCs). Moreover, impaired cellular metabolism was reported as a crucial pathogenic factor in CKD. By metabolomics analysis, we found that KD025 restored the metabolic disturbance, including the impaired glutathione metabolism in TGF-β1-stimulated tubular epithelial cells. Consistently, KD025 increased antioxidative stress enzymes and nuclear erythroid 2-related factor 2 (Nrf2) in fibrotic models. In addition, KD025 decreased the infiltration of macrophages and inflammatory response in fibrotic kidneys and blunted the activation of macrophages in vitro. In conclusion, inhibition of ROCK2 may serve as a potential novel therapy for renal tubulointerstitial fibrosis in CKD.

KD025, an anti-adipocyte differentiation drug, enhances the efficacy of conventional chemotherapeutic drugs in ABCG2-overexpressing leukemia cells

Most patients with advanced leukemia eventually die from multidrug resistance (MDR). Chemotherapy-resistant leukemia cells may lead to treatment failure and disease relapse. Overexpression of ATP-binding cassette subfamily G member 2 (ABCG2) leads to MDR, which serves as a potential biomarker and target of therapeutic intervention for leukemia cells. Targeting ABCG2 is a potential strategy for selective therapy and eradicate MDR cells, thus improving malignant leukemia treatment. KD025 (SLx-2119) is a novel Rho-associated protein kinase 2-selective inhibitor, which has been shown to inhibit adipogenesis in human adipose-derived stem cells and restore impaired immune homeostasis in autoimmunity therapy. The present study demonstrated that KD025 improved the efficacy of antineoplastic drugs in ABCG2-overexpressing leukemia cells and primary leukemia blast cells derived from patients with leukemia. Moreover, KD025 significantly inhibited the efflux of [³H]-mitoxantrone and hence accumulated higher levels of [³H]-mitoxantrone in HL60/ABCG2 cells. However, mechanistic research indicated that KD025 did not alter the protein levels and subcellular locations of ABCG2. KD025 may restrain the efflux activity of ABCG2 by obstructing ATPase activity. Taken together, KD025 can sensitize conventional antineoplastic drugs in ABCG2-overexpressing leukemia cells by blocking the pump function of ABCG2 protein. The present findings may provide a novel and useful combinational therapeutic strategy of KD025 and antineoplastic drugs for leukemia patients with ABCG2-mediated MDR.

Laquinimod Prevents Adipogenesis and Obesity by Down-Regulating PPAR-γ and C/EBPα through Activating AMPK

BACKGROUND AND PURPOSE

obesity is defined as excessive accumulation of adipose tissues and is becoming one of the main global severe public health issues. The present study aims to investigate the anti-adipogenesis of laquinimod and the underlying mechanism.

METHODS

a differentiation cocktail was used to differentiate 3T3-L1 cells, and mice were fed with high fat food to establish the obesity animal model. Oil red O staining, glycerol production assay, and the release of triglyceride were used to evaluate the differentiation degree of 3T3-L1 cells. The expression level of sterol regulatory element binding transcription factor 1 (Srebp1), fatty acid binding protein-4 (FABP4), glucose transporter 4 (GLUT4), peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT enhancer-binding proteins (C/EBPα), and phosphorylation of adenosine 5'-monophosphate (AMP)-activated protein kinase α (p-AMPKα) was determined by quantitative real time PCRqRT-PCR and western blot analysis. The pathological state of adipose tissues was evaluated by hematoxylin-eosin staining.

RESULTS

the amount and UV absorption of oil red O, glycerol production, release of triglyceride, and the expression of SREBP1, FABP4, and Glut4 in differentiated 3T3-L1 cells were decreased by the administration of laquinimod. PPAR-γ and C/EBPα were down-regulated, and p-AMPKα was up-regulated by laquinimod. The down-regulated PPAR-γ and C/EBPα, as well as the inhibited lipid accumulation functioned by laquinimod, were reversed by the coincubation with the AMPK inhibitor compound C. Decreased body weight, visceral adipocyte tissue weight, and size of adipocytes were observed in in vivo obesity mice after administration with laquinimod.

CONCLUSION

laquinimod might prevent adipogenesis by down-regulating PPAR-γ and C/EBPα through activating AMPK.

Automated lipid droplet quantification system for phenotypic analysis of adipocytes using CellProfiler

Adipogenic differentiation is the process by which preadipocytes become mature adipocytes, cells that store energy and regulate metabolic homeostasis. During differentiation, neutral lipids that accumulate in adipocytes can be detected using stains and used as an index of cell differentiation. However, imaging tools for evaluating intracellular lipid droplets remain at their infancy. Nutrition, stress, or chemical exposure can dysregulate adipogenic differentiation and lipid metabolism. Therefore, the aims of this study were to develop an accurate, standardized approach to quantify lipid droplet size of mature adipocytes and a clustering approach to analyze the total lipid content per adipocyte. For the lipid droplet analysis, we used two approaches, the free online computer software of reference, ImageJ, and another free online computer software, CellProfiler. For ImageJ, we used an already developed macro designed to identify particles and quantify their area, and for CellProfiler, we developed a new analysis pipeline. Our results show that CellProfiler is able to accurately identify a greater number of lipid droplets compared to ImageJ. A clustering analysis is also possible using CellProfiler which allows for the quantification of total lipid content per individual adipocyte to provide insight into single-cell responsiveness to adipogenic stimuli. CellProfiler streamlines the lipid droplet phenotypic analysis of adipocytes compared to more traditional analysis methods. In conclusion, this novel image analysis tool can provide a more precise evaluation of lipid droplet and adipogenesis dysregulation, a critical need in the understanding of metabolic disorders.

Determination of KD025 (SLx-2119), a Selective ROCK2 Inhibitor, in Rat Plasma by High-Performance Liquid Chromatography-Tandem Mass Spectrometry and its Pharmacokinetic Application

KD025 (SLx-2119), the first specific Rho-associated protein kinase 2 (ROCK2) inhibitor, is a potential new drug candidate currently undergoing several phase 2 clinical trials for psoriasis, idiopathic pulmonary fibrosis, chronic graft-versus-host disease, and systemic sclerosis. In this study, a bio-analytical method was developed and fully validated for the quantification of KD025 in rat plasma and for application in pharmacokinetic studies. KD025 and GSK429286A (the internal standard) in rat plasma samples were analyzed by high-performance liquid chromatography-tandem mass spectrometry with m/z transition values of 453.10 → 366.10 and 433.00 → 178.00, respectively. The method was fully validated according to the United State Food and Drug Administration guidelines in terms of selectivity, linearity, accuracy, precision, sensitivity, matrix effects, extraction recovery, and stability. The method enabled the quantification of KD025 levels in rat plasma following oral administration of 5 mg/kg KD025 and intravenous administration of 2 mg/kg KD025 to rats, respectively. Our findings suggest that the developed method is practical and reliable for pharmacokinetic studies of KD025 in preclinical animals.

MiRNAs and mRNAs Analysis during Abdominal Preadipocyte Differentiation in Chickens

Simple Summary

We sequenced the miRNAs and mRNAs of preabdominal fat cells and differentiated adipocytes, and target genes of miRNA combined with mRNA transcriptome data jointly. We found that the MAPK signal pathway, insulin signal pathway, fatty acid metabolism, ECM( extracellular matrix)–receptor interaction, and other signal pathways were involved in the differentiation of preabdominal fat cells. In addition, we found that some miRNAs–mRNAs combinations were strongly related to the differentiation of fat cells (miR-214−ACSBG2, NFKB2, CAMK2A, ACLY, CCND3, PLK3, ITGB2; miR-148a-5p−ROCK2; miR-10a-5p−ELOVL5; miR-146b-5p−LAMA4; miR-6615-5p−FLNB; miR-1774−COL6A1). Our findings provide important resources for the study of adipocyte differentiation.

Abstract

The excessive deposition of abdominal fat has become an important factor in restricting the production efficiency of chickens, so reducing abdominal fat deposition is important for improving growth rate. It has been proven that miRNAs play an important role in regulating many physiological processes of organisms. In this study, we constructed a model of adipogenesis by isolating preadipocytes (Ab-Pre) derived from abdominal adipose tissue and differentiated adipocytes (Ab-Ad) in vitro. Deep sequencing of miRNAs and mRNAs expressed in Ab-Pre and Ab-Ad groups was conducted to explore the effect of miRNAs and mRNAs on fat deposition. We identified 80 differentially expressed miRNAs (DEMs) candidates, 58 of which were up-regulated and 22 down-regulated. Furthermore, six miRNAs and six mRNAs were verified by qRT-PCR, and the results showed that the expression of the DEMs and differentially expressed genes (DEGs) in the two groups was consistent with our sequencing results. When target genes of miRNA were combined with mRNA transcriptome data, a total of 891 intersection genes were obtained, we predicted the signal pathways of cross genes enrichment to the MAPK signal pathway, insulin signal pathway, fatty acid metabolism, and ECM–receptor interaction. Meanwhile, we constructed miRNA and negatively correlated mRNA target networks, including 12 miRNA–mRNAs pairs, which showed a strong association with the abdominal adipocyte differentiation (miR-214−ACSBG2, NFKB2, CAMK2A, ACLY, CCND3, PLK3, ITGB2; miR-148a-5p−ROCK2; miR-10a-5p−ELOVL5; miR-146b-5p−LAMA4; miR-6615-5p−FLNB; miR-1774−COL6A1). Overall, these findings provide a background for further research on lipid metabolism. Thus, we can better understand the molecular genetic mechanism of chicken abdominal fat deposition.

Identification of novel functions of the ROCK2-specific inhibitor KD025 by bioinformatics analysis

Rho-associated protein kinases (ROCKs) have various cellular functions, which include actin cytoskeleton remodeling and vesicular trafficking, and there are two major mammalian ROCK isotypes, namely, ROCK1 (ROKβ) and ROCK2 (ROKα). The ROCK2-specific inhibitor KD025 (SLx-2119) is currently undergoing phase II clinical trials, but its cellular functions have not been fully explored. In this study, we investigated the functions of KD025 at the genomics level by bioinformatics analysis using the GSE8686 microarray dataset from the NCBI GEO database, in three different primary human cell lines. An initial microarray analysis conducted by Boerma et al. focused on the effects of KD025 on cell adhesion and blood coagulation, but did not provide comprehensive information on the functions of KD025. Our analysis of differentially expressed genes (DEGs) showed ~70% coincidence with Boerma et al.'s findings, and newly identified that CCND1, CXCL2, NT5E, and SMOX were differentially expressed by KD025. However, due to low numbers of co-regulated DEGs, we were unable to extract the functions of KD025 with significance. To overcome this limitation, we used gene set enrichment analysis (GSEA) and the heatmap hierarchical clustering method. We confirmed KD025 regulated inflammation and adipogenesis pathways, as previously reported experimentally. In addition, we found KD025 has novel regulatory functions on various pathways, including oxidative phosphorylation, WNT signaling, angiogenesis, and KRAS signaling. Further studies are required to systematically characterize these newly identified functions of KD025.

Effects of the Selective EP2 Receptor Agonist Omidenepag on Adipocyte Differentiation in 3T3-L1 Cells

Purpose: We aimed at comparing the effects of omidenepag (OMD) with those of prostaglandin F (FP) receptor agonists (FP agonists) on adipogenesis in mouse 3T3-L1 cells. Methods: To evaluate the agonistic activities of OMD against the mouse EP2 (mEP2) receptor, we determined cAMP contents in mEP2 receptor-expressing CHO cells by using radioimmunoassays. Overall, 3T3-L1 cells were cultured in differentiation medium for 10 days and adipocyte differentiation was assessed according to Oil Red O-stained cell areas. Changes in expression levels of the adipogenic transcription factors Pparg, Cebpa, and Cebpb were determined by using real-time polymerase chain reaction (PCR). OMD at 0.1, 1, 10, and 40 μmol/L, latanoprost free acid (LAT-A) at 0.1 μmol/L, or prostaglandin F_2α (PGF_2α), at 0.1 μmol/L were added to cell culture media during adipogenesis. Oil Red O-stained areas and expression patterns of transcription factor targets of OMD or FP agonists were compared with those of untreated controls. Results: The 50% effective concentration (EC₅₀) of OMD against the mEP2 receptor was 3.9 nmol/L. Accumulations of Oil Red O-stained lipid droplets were observed inside control cells on day 10. LAT-A and PGF_2α significantly inhibited the accumulation of lipid droplets; however, OMD had no effect on this process even at concentrations up to 40 μmol/L. LAT-A and PGF_2α significantly suppressed Pparg, Cebpa, and Cebpb gene expression levels during adipocyte differentiation. Conversely, OMD had no obvious effects on the expression levels of these genes. Conclusions: A selective EP2 receptor agonist, OMD, did not affect the adipocyte differentiation in 3T3-L1 cells, whereas FP agonists significantly inhibited this process.

The Rho GTPase RND3 regulates adipocyte lipolysis

BACKGROUND

Adipose tissue plays a crucial role in diet- and obesity-related insulin resistance, with implications for several metabolic diseases. Identification of novel target genes and mechanisms that regulate adipocyte function could lead to improved treatment strategies. RND3 (RhoE/Rho8), a Rho-related GTP-binding protein that inhibits Rho kinase (ROCK) signaling, has been linked to diverse diseases such as apoptotic cardiomyopathy, heart failure, cancer and type 2 diabetes, in part by regulating cytoskeleton dynamics and insulin-mediated glucose uptake.

RESULTS

We here investigated the expression of RND3 in adipose tissue in human obesity, and discovered a role for RND3 in regulating adipocyte metabolism. In cross-sectional and prospective studies, we observed 5-fold increased adipocyte levels of RND3 mRNA in obesity, reduced levels after surgery-induced weight loss, and positive correlations of RND3 mRNA with adipocyte size and surrogate measures of insulin resistance (HOMA2-IR and circulating triglyceride/high-density lipoprotein cholesterol (TAG/HDL-C) ratio). By screening for RND3-dependent gene expression following siRNA-mediated RND3 knockdown in differentiating human adipocytes, we found downregulation of inflammatory genes and upregulation of genes related to adipocyte ipolysis and insulin signaling. Treatment of adipocytes with tumor necrosis factor alpha (TNFα), lipopolysaccharide (LPS), hypoxia or cAMP analogs increased RND3 mRNA levels 1.5-2-fold. Functional assays in primary human adipocytes confirmed that RND3 knockdown reduces cAMP- and isoproterenol-induced lipolysis, which were mimicked by treating cells with ROCK inhibitor. This effect could partly be explained by reduced protein expression of adipose triglyceride lipase (ATGL) and phosphorylated hormone-sensitive lipase (HSL).

CONCLUSION

We here uncovered a novel differential expression of adipose RND3 in obesity and insulin resistance, which may at least partly depend on a causal effect of RND3 on adipocyte lipolysis.

KD025 (SLx-2119) suppresses adipogenesis at intermediate stage in human adipose-derived stem cells

Rho-associated kinases (ROCKs) have been reported to antagonize adipocyte differentiation, and inhibition of ROCKs by small molecules promotes adipogenesis. Surprisingly, our recent study revealed that the ROCK2-specific inhibitor KD025 (SLx-2119), suppresses differentiation at the intermediate stage in 3T3-L1 preadipocytes. To address whether the anti-adipogenic activity of KD025 is a generalizable property, we examined the effect of KD025 in human adipose-derived stem cells (hADSCs). KD025 significantly suppressed the adipocyte differentiation of hADSCs with downregulation of the protein and mRNA expression of various adipogenic and lipogenic markers, including PPARγ, C/EBPα, SREBP-1c, Glut4 and FABP4. Notably, we observed that adipocyte differentiation is effectively suppressed by exposure to KD025 during the mid-to-late period of adipogenesis but not at the earlier stages, showing stage-specificity. Contrary to expectations, KD025 upregulated the insulin signaling, as confirmed by the increased phosphorylation levels of Akt and GSK-3α/β, and the differentiation-promoting activity of insulin signaling was observed to be overwhelmed by the inhibitory activity. In addition, we observed that other ROCK inhibitors (Y-27632, fasudil, and H-1152P) did not suppress but promoted adipocyte differentiation. These results indicate that KD025 suppresses adipocyte differentiation by modulation of key factors activated at the intermediate stage of differentiation, and not by inhibition of ROCK2.

ROCK2 inhibition enhances the thermogenic program in white and brown fat tissue in mice

The RhoA/ROCK-mediated actin cytoskeleton dynamics have been implicated in adipogenesis. The two ROCK isoforms, ROCK1 and ROCK2, are highly homologous. The contribution of ROCK2 to adipogenesis in vivo has not been elucidated. The present study aimed at the in vivo and in vitro roles of ROCK2 in the regulation of adipogenesis and the development of obesity. We performed molecular, histological, and metabolic analyses in ROCK2^+/- and ROCK2^+/KD mouse models, the latter harboring an allele with a kinase-dead (KD) mutation. Both ROCK2^+/- and ROCK2^+/KD mouse models showed a lean body mass phenotype during aging, associated with increased amounts of beige cells in subcutaneous white adipose tissue (sWAT) and increased thermogenic gene expression in all fat depots. ROCK2^+/- mice on a high-fat diet showed increased energy expenditure accompanying by reduced obesity, and improved insulin sensitivity. In vitro differentiated ROCK2^+/- stromal-vascular (SV) cells revealed increased beige adipogenesis associated with increased thermogenic gene expressions. Treatment with a selective ROCK2 inhibitor, KD025, to inhibit ROCK2 activity in differentiated SV cells reproduced the pro-beige phenotype of ROCK2^+/- SV cells. In conclusion, ROCK2 activity-mediated actin cytoskeleton dynamics contribute to the inhibition of beige adipogenesis in WAT, and also promotes age-related and diet-induced fat mass gain and insulin resistance.

Cholesterol-dependent Modulation of Stem Cell Biomechanics: Application to Adipogenesis

Cell mechanics has been shown to regulate stem cell differentiation. We have previously reported that altered cell stiffness of mesenchymal stem cells can delay or facilitate biochemically directed differentiation. One of the factors that can affect the cell stiffness is cholesterol. However, the effect of cholesterol on differentiation of human mesenchymal stem cells (hMSCs) remains elusive. In this paper, we demonstrate that cholesterol is involved in the modulation of the cell stiffness and subsequent adipogenic differentiation. Rapid cytoskeletal actin reorganization was evident and correlated with the cell's Young's modulus measured using atomic force microscopy (AFM). In addition, the level of membrane-bound cholesterol was found to increase during adipogenic differentiation and inversely varied with the cell stiffness. Furthermore, cholesterol played a key role in the regulation of the cell morphology and biomechanics, suggesting its crucial involvement in mechanotransduction. To better understand the underlying mechanisms, we investigated the effect of cholesterol on the membrane-cytoskeleton linker proteins (ezrin and moesin). Cholesterol depletion was found to up-regulate the ezrin expression which promoted cell spreading, increased Young's modulus, and hindered adipogenesis. In contrast, cholesterol enrichment increased the moesin expression, decreased Young's modulus, and induced cell rounding and facilitated adipogenesis. Taken together, cholesterol appears to regulate the stem cell mechanics and adipogenesis through the membrane-associated linker proteins.