REST Is Not Resting: REST/NRSF in Health and Disease

Glycoprotein 130 improves repressor element‑1 silencing transcription factor‑related axon regenerative capacity in peripheral nerves with aging

Axon regenerative capacity diminishes with aging and differences in the condition of peripheral nerves between young and elderly individuals have been reported. However, the underlying pathology remains unclear. The expression of repressor element‑1 silencing transcription factor (REST) increases with age and is reported to suppress axon regeneration. The present study investigated the pathology and potential treatment of reduced axon regenerative capacity using REST‑regulated cells and a mouse model. This study examined the molecular expression of the janus kinase 1 (JAK1)/signal transducer and activator of transcription 3 (STAT3) pathway, which is involved in growth‑associated protein 43 (GAP43) expression. In REST‑overexpressed (REST‑OE), glycoprotein 130 (GP130), JAK1 and phosphorylated STAT3 (p‑STAT3) expression was decreased compared with the control (GP130, P=0.004; JAK1, P=0.038; pSTAT3, P=0.015). On the other hand, in REST‑low expressed (siREST), GP130, JAK1 and pSTAT3 expression was increased compared with the control (GP130, P=0.004; JAK1, P=0.003; pSTAT3, P=0.033). It suggested that GP130 plays an important role. Therefore, GP130 agonist was administered to REST‑OE and aged mice and resulted in a significant increase in GAP43 expression (REST‑OE: Protein P=0.018, mRNA P=0.040; aged mice: Protein P=0.016, mRNA P=0.013). The results of this study suggest that the pathology of reduction in peripheral nerve axon regenerative capacity is inhibited by age‑related increase in REST expression, which leads to decreased GP130 expression and inhibition of JAK1/STAT3 pathway activity. These findings suggest that regulating GP130 expression may improve axon regenerative capacity by aging.

REST contributes to renal fibrosis through inducing mitochondrial energy metabolism imbalance in tubular epithelial cells

BACKGROUND

Renal fibrosis represents the final common pathological manifestation of chronic kidney disease (CKD), yet the underlying mechanism remains elusive, and there is still a lack of effective targeted therapeutic strategy. Although previous research indicated that repressor element 1-silencing transcription factor (REST) contributed to acute kidney injury (AKI) in renal tubular epithelial cells (RTECs), its specific contribution to renal fibrosis and associated mechanisms remains largely unexplored.

METHODS

Renal biopsies from CKD patients were collected to evaluate the expression of REST. Kidney-specific Rest conditional knockout (Cdh16-Cre/Restflox/flox) mice were generated and employed unilateral ureter obstruction (UUO) models to investigate the role of REST in renal fibrosis. RNA sequencing was performed to elucidate the mechanism. Mitochondrial function was evaluated by transmission electron microscopy (TEM), reactive oxygen species (ROS), oxygen consumption rates (OCR), extracellular acidifcation rate (ECAR) and adenosine triphosphate (ATP). The severity of renal fibrosis was assessed through Western blot, immunofluorescent staining and immumohistochemical staining. Bioinformatic prediction, dual luciferase reporter gene assay, point mutation and chromatin immunoprecipitation (ChIP) assay were utilized to clarify the molecular mechanism.

RESULTS

REST was significantly up-regulated in the kidney tissues from CKD patients, UUO-induced fibrotic mouse models and TGF-β1-incubated RTECs. Notably, kidney-specific knockout of Rest prominently alleviated renal fibrosis by improving mitochondrial energy metabolism and restoring fatty acid oxidation. Mechanically, REST disturbed mitochondrial energy metabolism through repressing the transcription of oxoglutarate dehydrogenase-like (OGDHL) via directly binding to its promotor region. Further, pharmacological inhibition of REST using the specific REST inhibitor, X5050, significantly ameliorated the progression of renal fibrosis both in vitro and in vivo.

CONCLUSIONS

Our explorations revealed the upregulation of REST in renal fibrosis disrupts mitochondrial energy metabolism through transcriptionally suppressing OGDHL, which may act as a promising therapeutic target for renal fibrosis.

A Transcriptomic Comparison of the HD10.6 Human Sensory Neuron-Derived Cell Line with Primary and iPSC Sensory Neurons

A key concern in early-stage analgesic discovery efforts is the extent to which mechanisms identified in rodents will translate to humans. To evaluate an alternative approach to the use of rodent dissociated DRG neurons for in vitro analyses of nociceptive signaling, we performed a transcriptomic analysis of the HD10.6 human dorsal root ganglion (DRG)-derived immortalized cell line. We conducted RNA-seq on proliferating and mature HD10.6 cells to characterize transcriptional changes associated with maturation. We then compared the transcriptomes of HD10.6 cells and several recently developed lines of human induced pluripotent stem cell-derived sensory neurons (iPSC-SN) to single-nucleus RNA-seq data from human DRGs. HD10.6 cells showed the highest correlation with 3 human sensory neuron subtypes associated with nociception and pruriception. Each of the iPSC-SN lines evaluated showed a distinct pattern of correlation with human sensory neuron subtypes. We identified G protein-coupled receptors (GPCRs) and ion channels that are expressed in both HD10.6 cells and human DRG neurons, as well as numerous genes that are expressed in human DRG but not in rodent, underscoring the need for human sensory neuron in vitro models. Proof-of-concept evaluations of protein kinase A, protein kinase C and Erk signaling provide examples of scalable assays using HD10.6 cells to investigate well-established GPCR signaling pathways. We conclude that HD10.6 cells provide a versatile model for exploring human neuronal signaling mechanisms.

DNA methylation changes during acute COVID-19 are associated with long-term transcriptional dysregulation in patients' airway epithelial cells

Molecular changes underlying the persistent health effects after SARS-CoV-2 infection remain poorly understood. To discern the gene regulatory landscape in the upper respiratory tract of COVID-19 patients, we performed enzymatic DNA methylome and single-cell RNA sequencing in nasal cells of COVID-19 patients (n = 19, scRNA-seq n = 14) and controls (n = 14, scRNA-seq n = 10). In addition, we resampled a subset of these patients for transcriptome analyses at 3 (n = 7) and 12 months (n = 5) post infection and followed the expression of differentially regulated genes over time. Genome-wide DNA methylation analysis revealed 3112 differentially methylated regions between COVID-19 patients and controls. Hypomethylated regions affected immune regulatory genes, while hypermethylated regions were associated with genes governing ciliary function. These genes were not only downregulated in the acute phase of the disease but sustained repressed up to 12 months post infection in ciliated cells. Validation in an independent cohort collected 6 months post infection (n  = 15) indicated symptom-dependent transcriptional repression of ciliary genes. We therefore propose that hypermethylation observed in the acute phase may exert a long-term effect on gene expression, possibly contributing to post-acute COVID-19 sequelae.

Soluble Factors and Mechanisms Regulated by Sialylated IgG Signaling

Inflammation is a complex biological response that can be both induced and actively suppressed by IgG-Fc gamma receptor (FcγR) interactions. This review explores the role of IgG sialylation in reducing or blocking inflammatory responses. We first revisit foundational studies that established the anti-inflammatory properties of sialylated IgG1 Fc. These early investigations revealed that the sialylated fraction is crucial for intravenous immunoglobulin's (IVIg's) ability to reduce inflammation in many autoinflammatory diseases and defined a paracrine signaling mechanism underlying this activity. Next, we discuss a recently identified mechanism whereby sialylated IgG directly induces RE1-Silencing Transcription Factor (REST) which functions as a transcriptional repressor of NF-κB1. This mechanism suggests a very broad role for sialylated IgG signaling in inflammation control since NF-κB is a central mediator of responses downstream of diverse activating receptors on both adaptive and innate immune cells. Finally, we review a set of soluble factors that are suppressed by sialylated IgG signaling in the murine airway and in purified human macrophages, providing additional insight into mechanisms by which sialylated IgG contributes to broad inflammatory control.

Identification of FSH-regulated and estrous stage-specific transcriptional networks in mouse ovaries

Follicle-stimulating hormone (FSH) acts by binding to FSHRs expressed on ovarian granulosa cells and produces estradiol. FSH is essential for female fertility because mice lacking FSH (Fshb KO) are anestrous and infertile. Although several in vitro cell culture and ex vivo approaches combined with pharmacological hormone treatment were used to identify FSH-regulated genes, how FSH orchestrates ovarian gene networks in vivo has not been investigated. Whether FSH-regulated genes display estrous stage-specific expression changes has also not been studied. Here, we functionally rescued Fshb null mice with a gonadotrope-targeted HFSHB transgene and performed RNA-Seq analysis on ovarian RNAs obtained from FSH-intact (WT), FSH-deficient (Fshb KO), and FSH-rescue (HFSHB+ rescue) mice. By comparing WT vs. Fshb KO and Fshb KO vs. HFSHB+ rescue ovarian gene expression datasets, we identified FSH-responsive genes in vivo. Cross interrogation of these datasets further allowed us to identify several transcription factors (TFs) and RNA-binding proteins specific to FSH-regulated genes. In an independent set of experiments, we performed RNA-Seq analysis on ovarian RNAs from mice in diestrous (DE), proestrous (PE), and estrous (E) and identified estrous stage-specific ovarian gene expression patterns. Interestingly, many of the FSH-regulated TFs themselves were estrous-stage specifically expressed. We found that ESR2 and GATA6, two known FSH-responsive TFs, and their target genes are reciprocally regulated with distinct patterns of expression in estrous stages. Together, our in vivo models and RNA-Seq analyses identify FSH-regulated ovarian genes in specific estrous stages that are under transcriptional and posttranscriptional control.

IgG sialylation puts lung inflammation to REST

The mechanisms underpinning susceptibility to influenza virus infection, resulting in life-threatening disease, are not well understood. In this issue of Immunity, Chakraborty et al. demonstrate that sialylated IgG suppresses NF-κB-driven inflammatory responses in the lungs by inducing repressor element-1 silencing transcription factor (REST) to prevent excessive inflammation without impacting viral replication.

Sialylated IgG induces the transcription factor REST in alveolar macrophages to protect against lung inflammation and severe influenza disease

While most respiratory viral infections resolve with little harm to the host, severe symptoms arise when infection triggers an aberrant inflammatory response that damages lung tissue. Host regulators of virally induced lung inflammation have not been well defined. Here, we show that enrichment for sialylated, but not asialylated immunoglobulin G (IgG), predicted mild influenza disease in humans and was broadly protective against heterologous influenza viruses in a murine challenge model. Mechanistic studies show that sialylated IgG mediated this protection by inducing the transcription factor repressor element-1 silencing transcription factor (REST), which repressed nuclear factor κB (NF-κB)-driven responses, preventing severe lung inflammation and protecting lung function during influenza infection. Therapeutic administration of a recombinant, sialylated Fc molecule in clinical development similarly activated REST and protected against severe influenza disease, demonstrating that this pathway could be clinically harnessed. Overall, induction of REST through sialylated IgG signaling is a strategy to limit inflammatory disease sequelae in infections caused by antigenically distinct influenza strains.

KIF15 promotes human glioblastoma progression under the synergistic transactivation of REST and P300

Glioblastoma (GBM) is highly invasive and lethal. The failure to cure GBM highlights the necessity of developing more effective targeted therapeutic strategies. KIF15 is a motor protein to be involved in cell mitosis promotion, cell structure assembly and cell signal transduction. The precise biological function and the potential upstream regulatory mechanisms of KIF15 in GBM remain elusive. Here, we demonstrated that KIF15 was abnormally up-regulated in GBM and predicted poor prognosis of GBM patients. KIF15 promotes GBM cell proliferation, metastasis and cell cycle progression. REST could bind to KIF15 promoter and transactivate KIF15. Furthermore, REST interacts with P300 and depends on its histone acetyltransferase (HAT) activity to co-regulate KIF15 expression. Both REST and P300 were highly expressed in GBM and predicted poor prognosis of GBM patients alone or in combination with KIF15. The tumorigenic function of KIF15 in GBM was regulated by REST in vitro and in vivo and the combinational treatment of cell cycle inhibitor Palbociclib with P300 HAT inhibitor inhibited GBM xenografts survival more significantly. Our findings indicate that KIF15 promotes GBM progression under the synergistic transactivation of REST and P300. P300/REST/KIF15 signaling axis is expected to be served as a cascade of candidate therapeutic targets in anti-GBM.

Krüppel-like factors: potential roles in blood-brain barrier dysfunction and epileptogenesis

Epilepsy is a chronic and debilitating neurological disorder, known for the occurrence of spontaneous and recurrent seizures. Despite the availability of antiseizure drugs, 30% of people with epilepsy experience uncontrolled seizures and drug resistance, evidencing that new therapeutic options are required. The process of epileptogenesis involves the development and expansion of tissue capable of generating spontaneous recurrent seizures, during which numerous events take place, namely blood-brain barrier (BBB) dysfunction, and neuroinflammation. The consequent cerebrovascular dysfunction results in a lower seizure threshold, seizure recurrence, and chronic epilepsy. This suggests that improving cerebrovascular health may interrupt the pathological cycle responsible for disease development and progression. Krüppel-like factors (KLFs) are a family of zinc-finger transcription factors, encountered in brain endothelial cells, glial cells, and neurons. KLFs are known to regulate vascular function and changes in their expression are associated with neuroinflammation and human diseases, including epilepsy. Hence, KLFs have demonstrated various roles in cerebrovascular dysfunction and epileptogenesis. This review critically discusses the purpose of KLFs in epileptogenic mechanisms and BBB dysfunction, as well as the potential of their pharmacological modulation as therapeutic approach for epilepsy treatment.

The SWI/SNF PBAF complex facilitates REST occupancy at repressive chromatin

Multimeric SWI/SNF chromatin remodelers assemble into discrete conformations with unique complex functionalities difficult to dissect. Distinct cancers harbor mutations in specific subunits, altering the chromatin landscape, such as the PBAF-specific component ARID2 in melanoma. Here, we performed comprehensive epigenomic profiling of SWI/SNF complexes and their associated chromatin states in melanoma and melanocytes and uncovered a subset of PBAF-exclusive regions that coexist with PRC2 and repressive chromatin. Time-resolved approaches revealed that PBAF regions are generally less sensitive to ATPase-mediated remodeling than BAF sites. Moreover, PBAF/PRC2-bound loci are enriched for REST, a transcription factor that represses neuronal genes. In turn, absence of ARID2 and consequent PBAF complex disruption hinders the ability of REST to bind and inactivate its targets, leading to upregulation of synaptic transcripts. Remarkably, this gene signature is conserved in melanoma patients with ARID2 mutations. In sum, we demonstrate a unique role for PBAF in generating accessibility for a silencing transcription factor at repressed chromatin, with important implications for disease.

Integrative proteomic and transcriptomic analysis in the female goat ovary to explore the onset of puberty

Puberty is considered a prerequisite for affecting reproductive performance and productivity. Little was known about molecular changes in pubertal goat ovaries. Therefore, we measured and performed a correlation analysis of the mRNA and proteins changes in the pre-pubertal and pubertal goat ovaries. The results showed that only six differentially expressed genes and differentially abundant proteins out of 18,139 genes and 7550 proteins quantified had significant correlations. CNTN2 and THBS1, discovered in the mRNA-mRNA interaction network, probably participated in pubertal and reproductive regulation by influencing GnRH receptor signals, follicular development, and ovulation. The predicted core transcription factors may either promote or inhibit the expression of reproductive genes and act synergistically to maintain normal reproductive function in animals. The interaction between PKM and TIMP3 with other proteins may impact animal puberty through energy metabolism and ovarian hormone secretion. Pathway enrichment analyses revealed that the co-associated key pathways between ovarian genes and proteins at puberty included calcium signalling pathway and olfactory transduction. These pathways were associated with gonadotropin-releasing hormone synthesis and secretion, signal transmission, and cell proliferation. In summary, these results enriched the potential molecules and signalling pathways that affect puberty and provided new insights for regulating and promoting the onset of puberty. SIGNIFICANCE: This study conducted the first transcriptomic and proteomic correlation analysis of pre-pubertal and pubertal goat ovaries and identified six significantly correlated molecules at both the gene and protein levels. Meanwhile, we were drawn to several molecules and signalling pathways that may play a regulatory role in the onset of puberty and reproduction by influencing reproductive-related gene expression, GnRH receptor signals, energy metabolism, ovarian hormone secretion, follicular development, and ovulation. This information contributed to identify potential biomarkers in pubertal goat ovaries, which was vital for predicting the onset of puberty and improving livestock performance.

Epigenetic regulation in epilepsy: A novel mechanism and therapeutic strategy for epilepsy

Epilepsy is a common neurological disorder characterized by recurrent seizures with excessive and abnormal neuronal discharges. Epileptogenesis is usually involved in neuropathological processes such as ion channel dysfunction, neuronal injury, inflammatory response, synaptic plasticity, gliocyte proliferation and mossy fiber sprouting, currently the pathogenesis of epilepsy is not yet completely understood. A growing body of studies have shown that epigenetic regulation, such as histone modifications, DNA methylation, noncoding RNAs (ncRNAs), N6-methyladenosine (m6A) and restrictive element-1 silencing transcription factor/neuron-restrictive silencing factor (REST/NRSF) are also involved in epilepsy. Through epigenetic studies, we found that the synaptic dysfunction, nerve damage, cognitive dysfunction and brain development abnormalities are affected by epigenetic regulation of epilepsy-related genes in patients with epilepsy. However, the functional roles of epigenetics in pathogenesis and treatment of epilepsy are still to be explored. Therefore, profiling the array of genes that are epigenetically dysregulated in epileptogenesis is likely to advance our understanding of the mechanisms underlying the pathophysiology of epilepsy and may for the amelioration of these serious human conditions provide novel insight into therapeutic strategies and diagnostic biomarkers for epilepsy to improve serious human condition.