WNK4 is an Adipogenic Factor and Its Deletion Reduces Diet-Induced Obesity in Mice

Screening and identification of key biomarkers associated with endometriosis using bioinformatics and next-generation sequencing data analysis

Background

Endometriosis is a common cause of endometrial-type mucosa outside the uterine cavity with symptoms such as painful periods, chronic pelvic pain, pain with intercourse and infertility. However, the early diagnosis of endometriosis is still restricted. The purpose of this investigation is to identify and validate the key biomarkers of endometriosis.

Methods

Next-generation sequencing dataset GSE243039 was obtained from the Gene Expression Omnibus database, and differentially expressed genes (DEGs) between endometriosis and normal control samples were identified. After screening of DEGs, gene ontology (GO) and REACTOME pathway enrichment analyses were performed. Furthermore, a protein–protein interaction (PPI) network was constructed and modules were analyzed using the Human Integrated Protein–Protein Interaction rEference database and Cytoscape software, and hub genes were identified. Subsequently, a network between miRNAs and hub genes, and network between TFs and hub genes were constructed using the miRNet and NetworkAnalyst tool, and possible key miRNAs and TFs were predicted. Finally, receiver operating characteristic curve analysis was used to validate the hub genes.

Results

A total of 958 DEGs, including 479 upregulated genes and 479 downregulated genes, were screened between endometriosis and normal control samples. GO and REACTOME pathway enrichment analyses of the 958 DEGs showed that they were mainly involved in multicellular organismal process, developmental process, signaling by GPCR and muscle contraction. Further analysis of the PPI network and modules identified 10 hub genes, including vcam1, snca, prkcb, adrb2, foxq1, mdfi, actbl2, prkd1, dapk1 and actc1. Possible target miRNAs, including hsa-mir-3143 and hsa-mir-2110, and target TFs, including tcf3 (transcription factor 3) and clock (clock circadian regulator), were predicted by constructing a miRNA-hub gene regulatory network and TF-hub gene regulatory network.

Conclusions

This investigation used bioinformatics techniques to explore the potential and novel biomarkers. These biomarkers might provide new ideas and methods for the early diagnosis, treatment and monitoring of endometriosis.

WNKs regulate mouse behavior and alter central nervous system glucose uptake and insulin signaling

Certain areas of the brain involved in episodic memory and behavior, such as the hippocampus, express high levels of insulin receptors and glucose transporter-4 (GLUT4) and are responsive to insulin. Insulin and neuronal glucose metabolism improve cognitive functions and regulate mood in humans. Insulin-dependent GLUT4 trafficking has been extensively studied in muscle and adipose tissue, but little work has demonstrated either how it is controlled in insulin-responsive brain regions or its mechanistic connection to cognitive functions. In this study, we demonstrate that inhibition of WNK (With-No-lysine (K)) kinases improves learning and memory in mice. Neuronal inhibition of WNK enhances in vivo hippocampal glucose uptake. Inhibition of WNK enhances insulin signaling output and insulin-dependent GLUT4 trafficking to the plasma membrane in mice primary neuronal cultures and hippocampal slices. Therefore, we propose that the extent of neuronal WNK kinase activity has an important influence on learning, memory and anxiety-related behaviors, in part, by modulation of neuronal insulin signaling.

A missense mutation of the WNK1 gene affects cold tolerance in Chinese domestic cattle

Inclement weather conditions, especially cold stress, have threatened the cattle industry. Cattle exposed to cold environments for a longer time suffer developmental delay, immunity decline, and eventually death. WNK1 is a member of With-no-lysine kinases (WNKs), widely expressed in animal organs and tissues. WNK1 and WNK4 are expressed in adipose tissue, and WNK4 promotes adipogenesis. WNK1 does not directly affect adipogenesis but has been shown to promote WNK4 expression in several tissues or organs. One missense mutation NC_037346.1:g.107692244, A > G, rs208265410 in the WNK1 gene was detected from the database of bovine genomic variation (BGVD). Here, we collected 328 individuals of 17 breeds representing four groups of Chinese cattle, northern group cattle, southern group cattle, central group cattle, and special group cattle (Tibetan cattle). We also collected the temperature and humidity data records from their relative locations. The frequencies of the G allele in Chinese breeds increased from northern China to southern China, and the frequencies of the A allele showed an opposite trend. Our results indicate that the WNK1 gene might be a candidate gene marker associated with cold tolerance.

Targeting E3 ubiquitin ligases and their adaptors as a therapeutic strategy for metabolic diseases

Posttranslational modification of proteins via ubiquitination determines their activation, translocation, dysregulation, or degradation. This process targets a large number of cellular proteins, affecting all biological pathways involved in the cell cycle, development, growth, and differentiation. Thus, aberrant regulation of ubiquitination is likely associated with several diseases, including various types of metabolic diseases. Among the ubiquitin enzymes, E3 ubiquitin ligases are regarded as the most influential ubiquitin enzymes due to their ability to selectively bind and recruit target substrates for ubiquitination. Continued research on the regulatory mechanisms of E3 ligases and their adaptors in metabolic diseases will further stimulate the discovery of new targets and accelerate the development of therapeutic options for metabolic diseases. In this review, based on recent discoveries, we summarize new insights into the roles of E3 ubiquitin ligases and their adaptors in the pathogenesis of metabolic diseases by highlighting recent evidence obtained in both human and animal model studies.

NCC regulation by WNK signal cascade

With-no-lysine (K) (WNK) kinases have been identified as the causal genes for pseudohypoaldosteronism type II (PHAII), a rare hereditary hypertension condition characterized by hyperkalemia, hyperchloremic metabolic acidosis, and thiazide-hypersensitivity. We thought that clarifying the link between WNK and NaCl cotransporter (NCC) would bring us new mechanism(s) of NCC regulation. For the first time, we were able to produce a knock-in mouse model of PHAII and anti-phosphorylated NCC antibodies against the putative NCC phosphorylation sites and discover that constitutive activation of NCC and increased phosphorylation of NCC are the primary pathogenesis of the disease in vivo. We have since demonstrated that this regulatory mechanism is mediated by the kinases oxidative stress-response protein 1 (OSR1) and STE20/SPS1-related proline/alanine-rich kinase (SPAK) (WNK-OSR1/SPAK-NCC signaling cascade) and that the signaling is not only important in the pathological condition of PHAII but also plays a crucial physiological role in the regulation of NCC.

Effects of Gypenoside XLIX on fatty liver cell gene expression in vitro: a genome-wide analysis

OBJECTIVE

To perform Genome-wide analysis of Gypenoside XLIX (Gyp-XLIX) in the treatment of fatty liver cells.

METHODS

The gene profiles of 3 normal liver cells, 3 fatty liver cells, and 3 fatty liver cells treated with Gyp-XLIX were detected by high-throughput sequencing to identify the differentially expressed genes (DEGs) in fatty liver treated by Gyp-XLIX. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were used to explore the biological functions of DEGs. By constructing lncRNA-mRNA co-expression network of DEGs, network node genes were mined. Possible target genes of differentially expressed lncRNA were predicted by cis regulation.

RESULTS

782 DEGs were screened out; that is, 172 genes were highly expressed in fatty liver cells, and the expression decreased to the level of normal liver cells after Gyp-XLIX treatment; 610 genes were under expressed in fatty liver cells, and the expression increased to the level of normal liver cells after Gyp-XLIX treatment. Functional analysis of KEGG and GO showed that DEGs process DNA-binding transcription factor activity and ion transmembrane transporter activity in the plasma membrane region. This mediates glycerophospholipid metabolism, bile secretion, fatty acid degradation and other signaling pathways. lncRNA analysis showed that the expression of 16 lncRNAs was low in fatty liver cells, and the expression was increased to the level of normal liver cells after Gyp-XLIX treatment. Target gene prediction showed that 16 differentially expressed lncRNAs had cis potential to regulate target genes, among which lncRNA RPARP-AS1 had a high degree of relationship with other genes. lncRNA-mRNA co-expression network results showed that lncRNA RPARP-AS1 may acted on NFKB2.

CONCLUSION

LncRNA was differentially expressed in fatty liver cells and Gyp-XLIX treated fatty liver cells, and lncRNA RPARP-AS1 may be a regulatory gene in Gyp-XLIX treated fatty liver.

KLHL3 deficiency in mice ameliorates obesity, insulin resistance, and nonalcoholic fatty liver disease by regulating energy expenditure

Obesity is a growing global epidemic that can cause serious adverse health consequences, including insulin resistance (IR) and nonalcoholic fatty liver disease (NAFLD). Obesity development can be attributed to energy imbalance and metabolic inflexibility. Here, we demonstrated that lack of Kelch-like protein 3 (KLHL3) mitigated the development of obesity, IR, and NAFLD by increasing energy expenditure. KLHL3 mutations in humans cause Gordon’s hypertension syndrome; however, the role of KLHL3 in obesity was previously unknown. We examined differences in obesity-related parameters between control and Klhl3^−/− mice. A significant decrease in body weight concomitant with fat mass loss and improved IR and NAFLD were observed in Klhl3^−/− mice fed a high-fat (HF) diet and aged. KLHL3 deficiency inhibited obesity, IR, and NAFLD by increasing energy expenditure with augmentation of O₂ consumption and CO₂ production. Delivering dominant-negative (DN) Klhl3 using adeno-associated virus into mice, thereby dominantly expressing DN-KLHL3 in the liver, ameliorated diet-induced obesity, IR, and NAFLD. Finally, adenoviral overexpression of DN-KLHL3, but not wild-type KLHL3, in hepatocytes revealed an energetic phenotype with an increase in the oxygen consumption rate. The present findings demonstrate a novel function of KLHL3 mutation in extrarenal tissues, such as the liver, and may provide a therapeutic target against obesity and obesity-related diseases.

Mice that are genetically engineered to lack a protein involved in regulating energy expenditure are protected against the onset of obesity and the related problems of insulin resistance and non-alcoholic fatty liver disease. Jeong-Ki Min, Jong-Gil Park and colleagues at the Korea Research Institute of Bioscience & Biotechnology in South Korea, Daejon, discovered that the beneficial effect of the lack of the protein, called KLHL3, was due to an increase in energy expenditure. Mutations in the gene for KLHL3 are known to cause a variety of metabolic diseases in humans, including a form of high blood pressure called Gordon’s hypertension syndrome, but the protein’s role in human obesity has not been studied. The results suggest that drugs able to regulate the production or activity of KLHL3 might offer a new approach to treating obesity.

Diallyl Trisulfide Prevents Adipogenesis and Lipogenesis by Regulating the Transcriptional Activation Function of KLF15 on PPARγ to Ameliorate Obesity

SCOPE

Diallyl trisulfide (DATS) is a bioactive compound in garlic. The anti-obesity effect of garlic oil has been reported, but the role and mechanism of DATS in preventing obesity remain to be explored.

METHODS AND RESULTS

We performed studies with high-fat-diet-induced obese mice and 3T3-L1 adipocytes. The results showed that DATS significantly reduced lipid accumulation and repaired disordered metabolism in vivo by restraining adipogenesis and lipogenesis, and promoting lipolysis and fatty acid oxidation in white adipose tissue. In cells, DATS played different roles at different stages of adipocyte differentiation. Notably, DATS reduced lipid accumulation mainly by inhibiting adipogenesis and lipogenesis at the late stage. KLF15 was knocked down in 3T3-L1 cells, which eliminated the inhibitory effect of DATS on adipogenesis and lipogenesis. The dual-luciferase reporter and ChIP assays indicated that DATS could inhibit the transcriptional activation function of KLF15 on PPARγ by inhibiting the binding of KLF15 to PPARγ promoter. The function comparison of structural analogs and the intervention of dithiothreitol showed that disulfide bond was crucial for DATS to work.

CONCLUSION

DATS prevents obesity by regulating the transcriptional activation function of KLF15 on PPARγ. This article is protected by copyright. All rights reserved.

Human Umbilical Cord Mesenchymal Stem Cell-Based in vitro Model for Neurotoxicity Testing

Neurotoxicity (NT) testing for regulatory purposes is based on in vivo animal testing. There is general consensus, however, about the need for the development of alternative methodologies to allow researchers to more rapidly and cost effectively screen large numbers of chemicals for their potential to cause NT, or to investigate their mode of action. In vitro assays are considered an important source of information for making regulatory decisions, and human cell-based systems are recommended as one of the most relevant models in toxicity testing, to reduce uncertainty in the extrapolation of results from animal-based models. Human neuronal models range from various neuroblastoma cell lines to stem cell-derived systems, including those derived from mesenchymal stem/stromal cells (hMSC). hMSCs exhibit numerous advantages, including the fact that they can be obtained in high yield from healthy human adult tissues, can be cultured with a minimal laboratory setup and without genetic manipulations, are able of continuous and repeated self-renewal, are nontumorigenic, and can form large populations of stably differentiated cells representative of different tissues, including neuronal cells. hMSCs derived from human umbilical cord (hUC) in particular possess several prominent advantages, including a painless, non-invasive, and ethically acceptable collection procedure, simple and convenient preparation, and high proliferation capacity. In addition, hMSCs can be efficiently differentiated into neuron-like cells (hNLCs), which can then be used for the assessment of neuronal toxicity of potential neurotoxic compounds in humans. Here, we describe a step-by-step procedure to use hMSCs from the umbilical cord for in vitro neurotoxicity testing. First, we describe how to isolate, amplify, and store hMSCs derived from the umbilical cord. We then outline the steps to transdifferentiate these cells into hNLCs, and then use the hNLCs for neurotoxicity testing by employing multiple common cytotoxicity assays after treatment with test compounds. The approach follows the most updated guidance on using human cell-based systems. These protocols will allow investigators to implement an alternative system for obtaining primary NLCs of human origin, and support advancement in neurotoxicity research. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Isolation and maintenance of human mesenchymal stem/stromal cells (hMSCs) obtained from the umbilical cord lining membrane Basic Protocol 2: Transdifferentiation of hMSCs into neuron-like cells (hNLCs) and basic neurotoxicity assessment.

WNK1-TAK1 signaling suppresses lipopolysaccharide-induced cytokine production and classical activation in macrophages

With-no-lysine kinase (WNK) plays important roles in regulating electrolyte homeostasis, cell signaling, survival, and proliferation. It has been recently demonstrated that WNK1, a member of the WNK family, modifies the function of immune cells. Here we report that in macrophages, WNK1 has suppressive effects on lipopolysaccharide (LPS)-induced inflammatory responses via TGFβ-activated kinase 1 (TAK1)-mediated activation of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathway. We found that WNK1 heterozygous (WNK1^+/-) mice produced excessive proinflammatory cytokines in an experimental LPS-induced sepsis model, and peritoneal macrophages isolated from WNK1^+/- mice produced higher levels of LPS-induced cytokines and NOS2 expression as canonical proinflammatory M1 macrophage markers. We confirmed that small hairpin RNA (shRNA)-mediated knockdown of WNK1 activated LPS-induced cytokine production and NOS2 expression in RAW 264.7 macrophages. Moreover, we demonstrated that WNK1 knockdown increased the nuclear translocation of NF-κB and activated the p38 and Jun N-terminal kinase (JNK) MAPK signaling pathway and that a TAK1 inhibitor diminished these effects of WNK1 knockdown. These results suggest that WNK1 acts as a physiologic immune modulator via interactions with TAK1. WNK1 may be a therapeutic target against the cytokine storm caused by sepsis.

The WNK signaling pathway and salt-sensitive hypertension

The distal nephron of the kidney has a central role in sodium and fluid homeostasis, and disruption of this homeostasis due to mutations of with-no-lysine kinase 1 (WNK1), WNK4, Kelch-like 3 (KLHL3), or Cullin 3 (CUL3) causes pseudohypoaldosteronism type II (PHAII), an inherited hypertensive disease. WNK1 and WNK4 activate the NaCl cotransporter (NCC) at the distal convoluted tubule through oxidative stress-responsive gene 1 (OSR1)/Ste20-related proline-alanine-rich kinase (SPAK), constituting the WNK-OSR1/SPAK-NCC phosphorylation cascade. The level of WNK protein is regulated through degradation by the CUL3-KLHL3 E3 ligase complex. In the normal state, the activity of WNK signaling in the kidney is physiologically regulated by sodium intake to maintain sodium homeostasis in the body. In patients with PHAII, however, because of the defective degradation of WNK kinases, NCC is constitutively active and not properly suppressed by a high salt diet, leading to abnormally increased salt reabsorption and salt-sensitive hypertension. Importantly, recent studies have demonstrated that potassium intake, insulin, and TNFα are also physiological regulators of WNK signaling, suggesting that they contribute to the salt-sensitive hypertension associated with a low potassium diet, metabolic syndrome, and chronic kidney disease, respectively. Moreover, emerging evidence suggests that WNK signaling also has some unique roles in metabolic, cardiovascular, and immunological organs. Here, we review the recent literature and discuss the molecular mechanisms of the WNK signaling pathway and its potential as a therapeutic target.

WNK1 regulates skeletal muscle cell hypertrophy by modulating the nuclear localization and transcriptional activity of FOXO4

With-no-lysine (K) (WNK) kinases, which are mutated in the inherited form of hypertension pseudohypoaldosteronism type II, are essential regulators of membrane ion transporters. Here, we report that WNK1 positively regulates skeletal muscle cell hypertrophy via mediating the function of the pro-longevity transcription factor forkhead box protein O4 (FOXO4) independent of the conventional WNK signaling pathway linking SPS/STE20-related proline-alanine–rich kinase (SPAK)/oxidative stress response kinase 1 (OSR1) to downstream effector ion transporters. Small interfering RNA (siRNA)-mediated silencing of WNK1, but not SPAK/OSR1 kinases, induced myotube atrophy and remarkable increases in the mRNA expression of the muscle atrophy ubiquitin ligases MAFbx and MuRF1 in C2C12 mouse skeletal muscle cells. WNK1 silencing also increased FOXO4 nuclear localization, and co-transfection of Foxo4-targeted siRNA completely reversed the myotube atrophy and upregulation of atrogene transcription induced by WNK1 silencing. We further illustrated that WNK1 protein abundance in skeletal muscle was increased by chronic voluntary wheel running exercise (hypertrophic stimulus) and markedly decreased by adenine-induced chronic kidney disease (atrophic stimulus) in mice. These findings suggest that WNK1 is involved in the physiological regulation of mammalian skeletal muscle hypertrophy and atrophy via interactions with FOXO4. The WNK1-FOXO4 axis may be a potential therapeutic target in human diseases causing sarcopenia.

Synergistic co-regulation and competition by a SOX9-GLI-FOXA phasic transcriptional network coordinate chondrocyte differentiation transitions

The growth plate mediates bone growth where SOX9 and GLI factors control chondrocyte proliferation, differentiation and entry into hypertrophy. FOXA factors regulate hypertrophic chondrocyte maturation. How these factors integrate into a Gene Regulatory Network (GRN) controlling these differentiation transitions is incompletely understood. We adopted a genome-wide whole tissue approach to establish a Growth Plate Differential Gene Expression Library (GP-DGEL) for fractionated proliferating, pre-hypertrophic, early and late hypertrophic chondrocytes, as an overarching resource for discovery of pathways and disease candidates. De novo motif discovery revealed the enrichment of SOX9 and GLI binding sites in the genes preferentially expressed in proliferating and prehypertrophic chondrocytes, suggesting the potential cooperation between SOX9 and GLI proteins. We integrated the analyses of the transcriptome, SOX9, GLI1 and GLI3 ChIP-seq datasets, with functional validation by transactivation assays and mouse mutants. We identified new SOX9 targets and showed SOX9-GLI directly and cooperatively regulate many genes such as Trps1, Sox9, Sox5, Sox6, Col2a1, Ptch1, Gli1 and Gli2. Further, FOXA2 competes with SOX9 for the transactivation of target genes. The data support a model of SOX9-GLI-FOXA phasic GRN in chondrocyte development. Together, SOX9-GLI auto-regulate and cooperate to activate and repress genes in proliferating chondrocytes. Upon hypertrophy, FOXA competes with SOX9, and control toward terminal differentiation passes to FOXA, RUNX, AP1 and MEF2 factors.

In the development of the mammalian growth plate, while several transcription factors are individually well known for their key roles in regulating phases of chondrocyte differentiation, there is little information on how they interact and cooperate with each other. We took an unbiased genome wide approach to identify the transcription factors and signaling pathways that play dominant roles in the chondrocyte differentiation cascade. We developed a searchable library of differentially expressed genes, GP-DGEL, which has fine spatial resolution and global transcriptomic coverage for discovery of processes, pathways and disease candidates. Our work identifies a novel regulatory mechanism that integrates the action of three transcription factors, SOX9, GLI and FOXA. SOX9-GLI auto-regulate and cooperate to activate and repress genes in proliferating chondrocytes. Upon entry into prehypertrophy, FOXA competes with SOX9, and control of hypertrophy passes to FOXA, RUNX, AP1 and MEF2 factors.

MicroRNA-296: a promising target in the pathogenesis of atherosclerosis?

Atherosclerosis has been recognized as an inflammatory disease involving the vascular wall. MicroRNAs are a group of small noncoding RNAs to regulate gene expression at the transcriptional level through mRNA degradation or translation repression. Recent studies suggest that miR-296 may play crucial roles in the regulation of angiogenesis, inflammatory response, cholesterol metabolism, hypertension, cellular proliferation and apoptosis. In this review, we primarily discussed the molecular targets of miR-296 involved in the development of atherosclerosis, which may provide a basis for future investigation and a better understanding of the biological functions of miR-296 in atherosclerosis.

Inactivation of SPAK kinase reduces body weight gain in mice fed a high-fat diet by improving energy expenditure and insulin sensitivity

The STE20/SPS1-related proline-alanine-rich protein kinase (SPAK) controls the activity of the electroneutral cation-chloride cotransporters (SLC12 family) and thus physiological processes such as modulation of cell volume, intracellular chloride concentration [Cl^-]_i, and transepithelial salt transport. Modulation of SPAK kinase activity may have an impact on hypertension and obesity, as STK39, the gene encoding SPAK, has been suggested as a hypertension and obesity susceptibility gene. In fact, the absence of SPAK activity in mice in which the activating threonine in the T loop was substituted by alanine (SPAK-KI mice) is associated with decreased blood pressure; however its consequences in metabolism have not been explored. Here, we fed wild-type and homozygous SPAK-KI mice a high-fat diet for 17 wk to evaluate weight gain, circulating substrates and hormones, energy expenditure, glucose tolerance, and insulin sensitivity. SPAK-KI mice exhibit resistance to HFD-induced obesity and hepatic steatosis associated with increased energy expenditure, higher thermogenic activity in brown adipose tissue, increased mitochondrial activity in skeletal muscle, and reduced white adipose tissue hypertrophy mediated by augmented whole body insulin sensitivity and glucose tolerance. Our data reveal a previously unrecognized role for the SPAK kinase in the regulation of energy balance, thermogenesis, and insulin sensitivity, suggesting that this kinase could be a new drug target for the treatment of obesity and the metabolic syndrome.

Amentoflavone improves cardiovascular dysfunction and metabolic abnormalities in high fructose and fat diet-fed rats

Metabolic syndrome (MS) is a leading cause of mortality and morbidity in Western countries.