Endothelial cells regulated by RNF20 orchestrate the proliferation and differentiation of neural precursor cells during embryonic development

Identification of macrophage-related molecular subgroups and risk signature in colorectal cancer based on a bioinformatics analysis

Macrophages play a crucial role in tumor initiation and progression, while macrophage-associated gene signature in colorectal cancer (CRC) patients has not been investigated. Our study aimed to identify macrophage-related molecular subgroups and develop a macrophage-related risk model to predict CRC prognosis. The mRNA expression profile and clinical information of CRC patients were obtained from TCGA and GEO databases. CRC patients from TCGA were divided into high and low macrophage subgroups based on the median macrophage score. The ESTIMATE and CIBERSORT algorithms were used to assess immune cell infiltration between subgroups. GSVA and GSEA analyses were performed to investigate differences in enriched pathways between subgroups. Univariate and LASSO Cox regression were used to build a prognostic risk model, which was further validated in the GSE39582 dataset. A high macrophage score subgroup was associated with poor prognosis, highly activated immune-related pathways and an immune-active microenvironment. A total of 547 differentially expressed macrophage-related genes (DEMRGs) were identified, among which seven genes (including RIMKLB, UST, PCOLCE2, ZNF829, TMEM59L, CILP2, DTNA) were identified by COX regression analyses and used to build a risk score model. The risk model shows good predictive and diagnostic values for CRC patients in both TCGA and GSE39852 datasets. Furthermore, multivariate Cox regression analysis showed that the risk score was an independent risk factor for overall survival in CRC patients. Our findings provided a novel insight into macrophage heterogeneity and its immunological role in CRC. This risk score model may serve as an effective prognostic tool and contribute to personalised clinical management of CRC patients.

Unraveling the Role of Wnt Signaling Pathway in the Pathogenesis of Autism Spectrum Disorder (ASD): A Systematic Review

Autism spectrum disorder (ASD), or simply autism, is a neurodevelopmental disorder characterized by social communication deficit, restricted interests, and repetitive behavior. Several studies suggested a link between autism and the dysregulation of the Wnt signaling pathway which is mainly involved in cell fate determination, cell migration, cell polarity, neural patterning, and organogenesis. Despite the absence of effective therapy, significant progress has been made in understanding the pathogenesis of ASD. Neuropharmacological studies showed that drugs acting on the Wnt pathway like Canagliflozin can alleviate autistic-like behavior in animal models. Hence, this pathway could potentially be a futuristic therapeutic target to mitigate autism's symptoms. This systematic review aims to collect and analyze evidence that elucidates how alterations in the Wnt pathway may contribute to the pathogenesis of autism in animal models at the molecular, cellular, and physiological levels. Comprehensive searches were conducted across multiple databases, including PubMed, Web of Science, Embase, and Scopus to identify relevant studies up to March 2024. The inclusion criteria encompassed experimental studies that focused on the link between autism and this pathway, and the quality assessment was ensured by SYRCLE's risk of bias tools. Collectively, the included articles highlighted the possible implication of this pathway in the abnormalities found in autism, which impacted processes such as energy metabolism, oxidative stress, and neurogenesis. These alterations could underlie autistic behavior by affecting synaptic transmission and mitochondrial function.

Inhibition of CILP2 Improves Glucose Metabolism and Mitochondrial Dysfunction in Sarcopenia via the Wnt Signalling Pathway

BACKGROUND

Skeletal muscle is the primary organ involved in insulin-mediated glucose metabolism. Elevated levels of CILP2 are a significant indicator of impaired glucose tolerance and are predominantly expressed in skeletal muscle. It remains unclear whether CILP2 contributes to age-related muscle atrophy through regulating the glucose homeostasis and insulin sensitivity.

METHODS

Initially, the expression levels of CILP2 were assessed in elderly mice and patients with sarcopenia. Lentiviral vectors were used to induce either silencing or overexpression of CILP2 in C2C12 myoblast cells. The effects of CILP2 on proliferation, myogenic differentiation, insulin sensitivity and glucose uptake were evaluated using immunofluorescence, western blotting, real-time quantitative polymerase chain reaction, RNA sequencing, glucose uptake experiments, dual-luciferase reporter assays and co-immunoprecipitation (CO-IP). An adeno-associated virus-9 containing a muscle-specific promoter was injected into SAMP8 senile mice to observe the efficacy of CILP2 knockout.

RESULTS

We found that there was more CLIP2 expressed in the skeletal muscle of ageing mice (+1.1-fold, p < 0.01) and in patients with sarcopenia (+2.5-fold, p < 0.01) compared to the control group. Following the overexpression of CILP2, Ki67 (-65%, p < 0.01), PCNA (-32%, p < 0.05), MyoD1 (-89%, p < 0.001), MyoG (-31%, p < 0.05) and MyHC (-85%, p < 0.001), which indicate proliferation and differentiation potential, were significantly reduced. In contrast, MuRF-1 (+59%, p < 0.05), atrogin-1 (+43%, p < 0.05) and myostatin (+31%, p < 0.05), the markers of muscular atrophy, were significantly increased. Overexpression of CILP2 decreased insulin sensitivity, glucose uptake (-18%, p < 0.001), GLUT4 translocation to the membrane and the maximum respiratory capacity of mitochondria. Canonical Wnt signalling was identified through RNA sequencing as a potential pathway for CILP2 regulation in C2C12, and Wnt3a was confirmed as an interacting protein of CILP2 in the CO-IP assay. The addition of recombinant Wnt3a protein reversed the inhibitory effects on myogenesis and glucose metabolism caused by CILP2 overexpression. Conversely, CILP2 knockdown promoted myogenesis and glucose metabolism. CILP2 knockdown improved muscle atrophy in mice, characterized by significant increases in time to exhaustion (+42%, p < 0.001), grip strength (+19%, p < 0.01), muscle mass (+15%, p < 0.001) and mean muscle cross-sectional area (+37%, p < 0.01). CILP2 knockdown enhanced glycogen synthesis (+83%, p < 0.001) and the regeneration of oxidative and glycolytic muscle fibres in SAMP8 ageing mice via the Wnt/β-catenin signalling pathway.

CONCLUSIONS

Our results indicate that CILP2 interacts with Wnt3a to suppress the Wnt/β-catenin signalling pathway and its downstream cascade, leading to impaired insulin sensitivity and glucose metabolism in skeletal muscle. Targeting CILP2 inhibition could offer potential therapeutic benefits for sarcopenia.

RNF20-mediated transcriptional pausing and VEGFA splicing orchestrate vessel growth

Signal-responsive gene expression is essential for vascular development, yet the mechanisms integrating signaling inputs with transcriptional activities are largely unknown. Here we show that RNF20, the primary E3 ubiquitin ligase for histone H2B, plays a multifaceted role in sprouting angiogenesis. RNF20 mediates RNA polymerase (Pol II) promoter-proximal pausing at genes highly paused in endothelial cells, involved in VEGFA signaling, stress response, cell cycle control and mRNA splicing. It also orchestrates large-scale mRNA processing events that alter the bioavailability and function of critical pro-angiogenic factors, such as VEGFA. Mechanistically, RNF20 restricts ERG-dependent Pol II pause release at highly paused genes while binding to Notch1 to promote H2B monoubiquitination at Notch target genes and Notch-dependent gene expression. This balance is crucial, as loss of Rnf20 leads to uncontrolled tip cell specification. Our findings highlight the pivotal role of RNF20 in regulating VEGF-Notch signaling circuits during vessel growth, underscoring its potential for therapeutic modulation of angiogenesis.

FGD5 in basal cells induces CXCL14 secretion that initiates a feedback loop to promote murine mammary epithelial growth and differentiation

The interactions of environmental compartments with epithelial cells are essential for mammary gland development and homeostasis. Currently, the direct crosstalk between the endothelial niche and mammary epithelial cells remains poorly understood. Here, we show that faciogenital dysplasia 5 (FGD5) is enriched in mammary basal cells (BCs) and mediates critical interactions between basal and endothelial cells (ECs) in the mammary gland. Conditional deletion of Fgd5 reduced, whereas conditional knockin of Fgd5 increased, the engraftment and expansion of BCs, regulating ductal morphogenesis in the mammary gland. Mechanistically, murine mammary BC-expressed FGD5 inhibited the transcriptional activity of activating transcription factor 3 (ATF3), leading to subsequent transcriptional activation and secretion of CXCL14. Furthermore, activation of CXCL14/CXCR4/ERK signaling in primary murine mammary stromal ECs enhanced the expression of HIF-1α-regulated hedgehog ligands, which initiated a positive feedback loop to promote the function of BCs. Collectively, these findings identify functionally important interactions between BCs and the endothelial niche that occur through the FGD5/CXCL14/hedgehog axis.

Compromised cell competition exhausts neural stem cells pool

Blood vessels play a crucial role in maintaining the stem cell niche in both tumours and developing organs. Cell competition is critical for tumour progression. We hypothesise that blood vessels may act as a regulator of this process. As a pioneer, the secretions of blood vessels regulate the intensity of cell competition, which is essential for tumour invasion and developmental organ extension. Brd4 expresses highly in endothelial cells within various tumours and is positively correlated with numerous invasive genes, making it an ideal focal point for further research on the relationship between blood vessels and cell competition. Our results indicated that the absence of endothelial Brd4 led to a reduction in neural stem cell mortality and compromised cell competition. Endothelial Brd4 regulated cell competition was dependent on Testican2. Testican2 was capable of depositing Sparc and acted as a suppressor of Sparc. Compromised cell competition resulted in the depletion of neural stem cells and accelerated brain ageing. Testican2 could rescue the run-off of neural stem cells and accelerate the turnover rate of neurons. AD patients show compromised cell competition. Through the cloning of a point mutant of Brd4 identified in a subset of AD patients, it was demonstrated that the mutant lacked the ability to promote cell competition. This study suggests a novel approach for treating age-related diseases by enhancing the intensity of cell competition.

Systems genetics analysis reveals the common genetic basis for pain sensitivity and cognitive function

BACKGROUND

There is growing evidence of a strong correlation between pain sensitivity and cognitive function under both physiological and pathological conditions. However, the detailed mechanisms remain largely unknown. In the current study, we sought to explore candidate genes and common molecular mechanisms underlying pain sensitivity and cognitive function with a transcriptome-wide association study using recombinant inbred mice from the BXD family.

METHODS

The pain sensitivity determined by Hargreaves' paw withdrawal test and cognition-related phenotypes were systematically analyzed in 60 strains of BXD mice and correlated with hippocampus transcriptomes, followed by quantitative trait locus (QTL) mapping and systems genetics analysis.

RESULTS

The pain sensitivity showed significant variability across the BXD strains and co-varies with cognitive traits. Pain sensitivity correlated hippocampual genes showed a significant involvement in cognition-related pathways, including glutamatergic synapse, and PI3K-Akt signaling pathway. Moreover, QTL mapping identified a genomic region on chromosome 4, potentially regulating the variation of pain sensitivity. Integrative analysis of expression QTL mapping, correlation analysis, and Bayesian network modeling identified Ring finger protein 20 (Rnf20) as the best candidate. Further pathway analysis indicated that Rnf20 may regulate the expression of pain sensitivity and cognitive function through the PI3K-Akt signaling pathway, particularly through interactions with genes Ppp2r2b, Ppp2r5c, Col9a3, Met, Rps6, Tnc, and Kras.

CONCLUSIONS

Our study demonstrated that pain sensitivity is associated with genetic background and Rnf20-mediated PI3K-Akt signaling may involve in the regulation of pain sensitivity and cognitive functions.

Impact of Ring Finger Protein 20 and Its Downstream Regulation on Renal Tubular Injury in a Unilateral Nephrectomy Mouse Model Fed a High-Fat Diet

Abnormal lipid metabolism increases the relative risk of kidney disease in patients with a single kidney. Using transcriptome analysis, we investigated whether a high-fat diet leads to abnormalities in lipid metabolism and induces kidney cell-specific damage in unilateral nephrectomy mice. Mice with unilateral nephrectomy fed a high-fat diet for 12 weeks exhibited progressive renal dysfunction in proximal tubules, including lipid accumulation, vacuolization, and cell damage. Ring finger protein 20 (RNF20) is a ligase of nuclear receptor corepressor of peroxisome proliferator-activated receptors (PPARs). The transcriptome analysis revealed the involvement of RNF20-related transcriptome changes in PPAR signaling, lipid metabolism, and water transmembrane transporter under a high-fat diet and unilateral nephrectomy. In vitro treatment of proximal tubular cells with palmitic acid induced lipotoxicity by altering RNF20, PPARα, and ATP-binding cassette subfamily A member 1 (ABCA1) expression. PPARγ and aquaporin 2 (AQP2) expression decreased in collecting duct cells, regulating genetic changes in the water reabsorption process. In conclusion, a high-fat diet induces lipid accumulation under unilateral nephrectomy via altering RNF20-mediated regulation and causing functional damage to cells as a result of abnormal lipid metabolism, thereby leading to structural and functional kidney deterioration.

Type H blood vessels in coupling angiogenesis-osteogenesis and its application in bone tissue engineering

One specific capillary subtype, termed type H vessel, has been found with unique functional characteristics in coupling angiogenesis with osteogenesis. Researchers have fabricated a variety of tissue engineering scaffolds to enhance bone healing and regeneration through the accumulation of type H vessels. However, only a limited number of reviews discussed the tissue engineering strategies for type H vessel regulation. The object of this review is to summary the current utilizes of bone tissue engineering to regulate type H vessels through various signal pathways including Notch, PDGF-BB, Slit3, HIF-1α, and VEGF signaling. Moreover, we give an insightful overview of recent research progress about the morphological, spatial and age-dependent characteristics of type H blood vessels. Their unique role in tying angiogenesis and osteogenesis together via blood flow, cellular microenvironment, immune system and nervous system are also summarized. This review article would provide an insight into the combination of tissue engineering scaffolds with type H vessels and identify future perspectives for vasculized tissue engineering research.