Zbtb20 Regulates Developmental Neurogenesis in the Olfactory Bulb and Gliogenesis After Adult Brain Injury

INSTINCT: Multi-sample integration of spatial chromatin accessibility sequencing data via stochastic domain translation

Recent advances in spatial epigenomic techniques have given rise to spatial assay for transposase-accessible chromatin using sequencing (spATAC-seq) data, enabling the characterization of epigenomic heterogeneity and spatial information simultaneously. Integrative analysis of multiple spATAC-seq samples, for which no method has been developed, allows for effective identification and elimination of unwanted non-biological factors within the data, enabling comprehensive exploration of tissue structures and providing a holistic epigenomic landscape, thereby facilitating the discovery of biological implications and the study of regulatory processes. In this article, we present INSTINCT, a method for multi-sample INtegration of Spatial chromaTIN accessibility sequencing data via stochastiC domain Translation. INSTINCT can efficiently handle the high dimensionality of spATAC-seq data and eliminate the complex noise and batch effects of samples through a stochastic domain translation procedure. We demonstrate the superiority and robustness of INSTINCT in integrating spATAC-seq data across multiple simulated scenarios and real datasets. Additionally, we highlight the advantages of INSTINCT in spatial domain identification, visualization, spot-type annotation, and various downstream analyses, including motif enrichment analysis, expression enrichment analysis, and partitioned heritability analysis.

RNA-Seq transcriptome analysis of renal tissue from spontaneously hypertensive rats revealed renal protective effects of dapagliflozin, an inhibitor of sodium-glucose cotransporter 2

Hypertensive nephropathy (HTN) is a common complication of hypertension. Although various agents for treatment of hypertension exert significant effects, there is currently no effective treatment for hypertensive nephropathy. Sodium-glucose cotransporter 2 (SGLT2) inhibitors, such as dapagliflozin (DAPA), are a new class of hypoglycemic agents shown to improve the prognosis of patients with chronic kidney disease and diabetes mellitus. However, the mechanisms underlying the protective effects of DAPA remain unclear. RNA-sequencing (RNA-Seq)-based computational analysis was conducted to explore the transcriptomic changes to spontaneously hypertensive rats (SHRs) treated with DAPA for 8 weeks. Differentially expressed genes in SHRs were related to dysregulation of lipid metabolism, oxidation-reduction reaction, immunity and inflammation in HTN. Transcriptome analysis showed that 8 weeks of DAPA therapy exerted protective effects on the renal tissues of SHRs through the lysosomal, phagosomal, and autophagic pathways. VENN diagram analysis identified Zinc finger and BTB domain-containing 20 (Zbtb20) as the potential target of DAPA therapy. Consistent with the RNA-Seq findings, real-time quantitative PCR and immunohistochemical analyses revealed increased expression of Zbtb20 in the renal tissues of SHRs, whereas expression was decreased following 8 weeks of DAPA administration. The results of this study clarified the transcriptome signature of HTN and the beneficial effects of DAPA on renal tissues by alleviating dysregulation of metabolic processes and reducing inflammation.

Transcription Factor Zbtb20 as a Regulator of Malignancy and Its Practical Applications

Zbtb20 (zinc finger and BTB domain-containing protein 20) is a transcription factor with a zinc finger DNA binding domain and a BTB domain responsible for protein-protein interaction. Recently, this TF has received attention because new data showed its pivotal involvement in normal neural development and its regulatory effects on proliferation and differentiation in different tissues. Zbtb20 was shown to increase proliferation and migration and confer resistance to apoptosis in the contexts of many malignant tumors like hepatocellular carcinoma, non-small-cell lung carcinoma, gastric adenocarcinoma, glioblastoma multiforme, breast cancer, and acute myeloid leukemia. The involvement of Zbtb20 in tumor biology is best studied in hepatocellular carcinoma, where it is a promising candidate as an immunohistochemical tumor marker or may be used in patient screening. Here we review the current data connecting Zbtb20 with malignant tumors.

Age-Associated Changes in Endothelial Transcriptome and Epigenetic Landscapes Correlate With Elevated Risk of Cerebral Microbleeds

Background Stroke is a leading global cause of human death and disability, with advanced aging associated with elevated incidences of stroke. Despite high mortality and morbidity of stroke, the mechanisms leading to blood-brain barrier dysfunction and development of stroke with age are poorly understood. In the vasculature of brain, endothelial cells (ECs) constitute the core component of the blood-brain barrier and provide a physical barrier composed of tight junctions, adherens junctions, and basement membrane. Methods and Results We show, in mice, the incidents of intracerebral bleeding increases with age. After isolating an enriched population of cerebral ECs from murine brains at 2, 6, 12, 18, and 24 months, we studied age-associated changes in gene expression. The study reveals age-dependent dysregulation of 1388 genes, including many involved in the maintenance of the blood-brain barrier and vascular integrity. We also investigated age-dependent changes on the levels of CpG methylation and accessible chromatin in cerebral ECs. Our study reveals correlations between age-dependent changes in chromatin structure and gene expression, whereas the dynamics of DNA methylation changes are different. Conclusions We find significant age-dependent downregulation of the Aplnr gene along with age-dependent reduction in chromatin accessibility of promoter region of the Aplnr gene in cerebral ECs. Aplnr is associated with positive regulation of vasodilation and is implicated in vascular health. Altogether, our data suggest a potential role of the apelinergic axis involving the ligand apelin and its receptor to be critical in maintenance of the blood-brain barrier and vascular integrity.

Glial Populations in the Human Brain Following Ischemic Injury

There is a growing interest in glial cells in the central nervous system due to their important role in maintaining brain homeostasis under physiological conditions and after injury. A significant amount of evidence has been accumulated regarding their capacity to exert either pro-inflammatory or anti-inflammatory effects under different pathological conditions. In combination with their proliferative potential, they contribute not only to the limitation of brain damage and tissue remodeling but also to neuronal repair and synaptic recovery. Moreover, reactive glial cells can modulate the processes of neurogenesis, neuronal differentiation, and migration of neurons in the existing neural circuits in the adult brain. By discovering precise signals within specific niches, the regulation of sequential processes in adult neurogenesis holds the potential to unlock strategies that can stimulate the generation of functional neurons, whether in response to injury or as a means of addressing degenerative neurological conditions. Cerebral ischemic stroke, a condition falling within the realm of acute vascular disorders affecting the circulation in the brain, stands as a prominent global cause of disability and mortality. Extensive investigations into glial plasticity and their intricate interactions with other cells in the central nervous system have predominantly relied on studies conducted on experimental animals, including rodents and primates. However, valuable insights have also been gleaned from in vivo studies involving poststroke patients, utilizing highly specialized imaging techniques. Following the attempts to map brain cells, the role of various transcription factors in modulating gene expression in response to cerebral ischemia is gaining increasing popularity. Although the results obtained thus far remain incomplete and occasionally ambiguous, they serve as a solid foundation for the development of strategies aimed at influencing the recovery process after ischemic brain injury.

MicroRNA Expression Profile in TSC Cell Lines and the Impact of mTOR Inhibitor

The aim of this study was to assess the potential implication of microRNA on tuberous sclerosis (TSC) pathogenesis by performing microRNA profiling on cell lines silencing TSC1 or TSC2 genes using qPCR panels, before and after incubation with rapamycin. Significant differences in expression were observed between samples before and after rapamycin treatment in nineteen miRNAs in TSC1, five miRNAs in TSC2 and seven miRNAs in controls. Of miRNAs dysregulated before rapamycin treatment, three normalized after treatment in the TSC1 group (miR-21-3p, miR-433-3p, let-7g-3p) and one normalized in the TSC2 group (miR-1224-3p). Of the miRNAs dysregulated before rapamycin treatment in the TSC1 and TSC2 groups, two did not normalize after treatment (miR-33a-3p, miR-29a-3p). The results of the possible targets indicated that there are four common genes with seed regions susceptible to regulation by those miRNAs: ZBTB20, PHACTR2, PLXNC1 and ATP1B4. Our data show no changes in mRNA expression of these targets after rapamycin treatment. In conclusion, results of our study indicate the involvement of miRNA dysregulation in the pathogenesis of TSC. Some of the miRNA might be used as markers of treatment efficacy and autonomic miRNA as a target for future therapy.

Expression of Transcription Factor ZBTB20 in the Adult Primate Neurogenic Niche under Physiological Conditions or after Ischemia

The Zbtb20 gene encodes for a transcription factor that plays an important role in mammalian cortical development. Recently, its expression was reported in the adult mouse subventricular zone (SVZ), a major neurogenic niche containing neural stem cells throughout life. Here, we analyzed its expression in the adult primate anterior SVZ (SVZa) and rostral migratory stream (RMS) using macaque monkeys (Macaca fuscata). We report that the majority of Ki67+ cells, 71.4% in the SVZa and 85.7% in the RMS, co-label for ZBTB20. Nearly all neuroblasts, identified by their Doublecortin expression, were positive for ZBTB20 in both regions. Nearly all GFAP+ neural stem cells/astrocytes were also positive for ZBTB20. Analysis of images derived from a public database of gene expression in control/ischemic monkey SVZa, showed evidence for ZBTB20 upregulation in postischemic monkey SVZa. Furthermore, the co-localization of ZBTB20 with Doublecortin and Ki67 was increased in the postischemic SVZa. Our results suggest that ZBTB20 expression is evolutionarily conserved in the mammalian neurogenic niche and is reactive to ischemia. This opens the possibility for further functional studies on the role of this transcription factor in neurogenesis in primates.

Ghrelin Regulates Expression of the Transcription Factor Pax6 in Hypoxic Brain Progenitor Cells and Neurons

The nature of brain impairment after hypoxia is complex and recovery harnesses different mechanisms, including neuroprotection and neurogenesis. Experimental evidence suggests that hypoxia may trigger neurogenesis postnatally by influencing the expression of a variety of transcription factors. However, the existing data are controversial. As a proof-of-principle, we subjected cultured cerebral cortex neurons, cerebellar granule neurons and organotypic cerebral cortex slices from rat brains to hypoxia and treated these cultures with the hormone ghrelin, which is well-known for its neuroprotective functions. We found that hypoxia elevated the expression levels and stimulated nuclear translocation of ghrelin’s receptor GHSR1 in the cultured neurons and the acute organotypic slices, whereas ghrelin treatment reduced the receptor expression to normoxic levels. GHSR1 expression was also increased in cerebral cortex neurons of mice with induced experimental stroke. Additional quantitative analyses of immunostainings for neuronal proliferation and differentiation markers revealed that hypoxia stimulated the proliferation of neuronal progenitors, whereas ghrelin application during the phase of recovery from hypoxia counteracted these effects. At the mechanistic level, we provide a link between the described post-ischemic phenomena and the expression of the transcription factor Pax6, an important regulator of neural progenitor cell fate. In contrast to the neurogenic niches in the brain where hypoxia is known to increase Pax6 expression, the levels of the transcription factor in cultured hypoxic cerebral cortex cells were downregulated. Moreover, the application of ghrelin to hypoxic neurons normalised the expression levels of these factors. Our findings suggest that ghrelin stimulates neurogenic factors for the protection of neurons in a GHSR1-dependent manner in non-neurogenic brain areas such as the cerebral cortex after exposure to hypoxia.

An epigenetic circuit controls neurogenic programs during neocortex development

The production and expansion of intermediate progenitors (IPs) are essential for neocortical neurogenesis during development and over evolution. Here, we have characterized an epigenetic circuit that precisely controls neurogenic programs, particularly properties of IPs, during neocortical development. The circuit comprises a long non-coding RNA (LncBAR) and the BAF (SWI/SNF) chromatin-remodeling complex, which transcriptionally maintains the expression of Zbtb20. LncBAR knockout neocortex contains more deep-layer but fewer upper-layer projection neurons. Intriguingly, loss of LncBAR promotes IP production, but paradoxically prolongs the duration of the cell cycle of IPs during mid-later neocortical neurogenesis. Moreover, in LncBAR knockout mice, depletion of the neural progenitor pool at embryonic stage results in fewer adult neural progenitor cells in the subventricular zone of lateral ventricles, leading to a failure in adult neurogenesis to replenish the olfactory bulb. LncBAR binds to BRG1, the core enzymatic component of the BAF chromatin-remodeling complex. LncBAR depletion enhances association of BRG1 with the genomic locus of, and suppresses the expression of, Zbtb20, a transcription factor gene known to regulate both embryonic and adult neurogenesis. ZBTB20 overexpression in LncBAR-knockout neural precursors reverses compromised cell cycle progressions of IPs.

Zinc finger and BTB domain-containing protein 20 aggravates angiotensin II-induced cardiac remodeling via the EGFR-AKT pathway

Zinc finger and BTB domain-containing protein 20 (ZBTB20) play an important role in glucose and lipid homeostasis. ZBTB20 was shown to be a crucial protein for the maintenance of cardiac contractile function. However, the role of ZBTB20 in cardiac response remodeling has not been elucidated. Thus, this study aimed to explore the role of ZBTB20 in cardiac remodeling following angiotensin II insult. Mice were subjected to angiotensin II infusion to induce a cardiac adverse remodeling model. An adeno-associated virus (AAV) 9 system was used to deliver ZBTB20 to the mouse heart. Here, we demonstrate that ZBTB20 expression is elevated in angiotensin II-induced cardiac remodeling and in response to cardiomyocyte insults. Furthermore, AAV9-mediated overexpression of ZBTB20 caused cardiac wall hypertrophy, chamber dilation, increased fibrosis, and reduced ejection fraction. Additionally, ZBTB20 siRNA protected cardiomyocytes from angiotensin II-induced hypertrophy. Mechanistically, ZBTB20 interferes with EGFR and Akt signaling and modulates the remodeling response. Overexpression of constitutively active Akt counteracts ZBTB20 knockdown-mediated protection of adverse cardiac remodeling. These findings illustrate the role of ZBTB20 in the transition of adverse cardiac remodeling toward heart failure and provide evidence for the molecular programs inducing adverse cardiac remodeling. KEY MESSAGES: ZBTB20 is a transcription factor from the POK family. ZBTB20 is upregulated in heart tissue treated with angiotensin II. ZBTB20 influences cardiomyocyte hypertrophy via the EGFR-Akt pathway. Akt continuous activation leads to similar results to ZBTB20 overexpression.

ZBTB20 in Nociceptive Neurons of the Trigeminal Ganglia Regulates Pruritus

Recent studies have shown that ZBTB20, a zinc-finger protein containing transcription factor, is highly expressed in small-diameter primary sensory neurons in mice, and modulates pain through regulating TRP channels. However, whether ZBTB20 regulates itch sensation has not been demonstrated. In this study, small-diameter primary sensory neuron-specific ZBTB20 knockout (PN-ZB20KO) mice were used to investigate the role of ZBTB20 in the regulation of itch sensation. First, both histamine-dependent and non-histamine-dependent itch behaviors induced by injection of histamine and chloroquine (CQ) into the cheek were significantly diminished in PN-ZB20KO mice. Second, double immunohistochemistry showed that ZBTB20 was mainly expressed in CGRP-labeled small peptidergic neurons and was expressed at low levels in IB4-labeled small non-peptidergic and NF200-labeled large neurons in the trigeminal ganglia (TG). ZBTB20 was also expressed in most TRPV1⁺ and TRPA1⁺ neurons and to a lesser extent in TRPM8⁺ neurons in the TG. Furthermore, cheek injection of histamine and CQ enhanced the mRNA expression of TRPV1 and TRPA1 but not TRPM8 in the TG. Moreover, TRPV1 and TRPA1 knockout (KO) mice exhibited attenuation of itch behavior induced by histamine and CQ, respectively. Finally, silencing endogenous ZBTB20 with recombinant lentivirus expressing a short hairpin RNA against ZBTB20 (LV-shZBTB20) in TG neurons attenuated histamine- and non-histamine-induced itch and downregulated TRP channels in the TG. Our study suggests that ZBTB20 plays an important role in mediating itch in small primary sensory neurons.

Gross and Histopathology of COVID-19 With First Histology Report of Olfactory Bulb Changes

In nearly a year since the first reported cases of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a lot has been established about the virus. Correlates in regards to the biology and cellular effects of SARS-CoV-2 have brought a lot of explanations to the clinical manifestations of the disease and possible therapeutic modalities. However, despite the discoveries made, the tropism of SARS-CoV-2 has not yet been fully established, nor have all the clinical aspects of COVID-19. Herein we report the gross and histological findings in two diseased patients. Apart from the already established pulmonary and vascular changes caused by SARS-CoV-2, we report the presence of histological changes of the olfactory bulbs and frontal lobes of the brain, which may present as a correlate for COVID-19 related anosmia. The olfactory bulbs histologically showed necrotizing olfactory bulbitis. As both the olfactory bulb and frontal lobe of the cerebrum are key areas of olfaction, we believe that this tropism of SARS-CoV-2 may be key to the development of anosmia and not changes within the nasal cavity.

Zbtb20 deficiency causes cardiac contractile dysfunction in mice

The zinc-finger protein ZBTB20 regulates development and metabolism in multiple systems, and is essential for postnatal survival in mice. However, its potential role in the cardiovascular system remains undefined. Here, we demonstrate that ZBTB20 is critically involved in the regulation of cardiac contractility and blood pressure in mice. At the age of 16 days, the relatively healthy Zbtb20-null mice exhibited hypotension without obvious change of heart rate or other evidence for heart failure. Moreover, Zbtb20 deletion led to a marked reduction in heart size, left ventricular wall thickness, and cell size of cardiomyocytes, which was largely proportional to the decreased body growth. Notably, echocardiographic and hemodynamic analyses showed that cardiac contractility was greatly impaired in the absence of ZBTB20. Mechanistically, ZBTB20 deficiency decreased cardiac ATP contents, and compromised the enzyme activity of mitochondrial complex I in heart as well as L-type calcium current density in cardiomyocytes. Furthermore, the developmental activation of some mitochondrial function-related genes was significantly attenuated in Zbtb20-null myocardium, which included Hspb8, Ckmt2, Cox7a1, Tfrc, and Ogdhl. Put together, these results suggest that ZBTB20 plays a crucial role in the regulation of heart development, energy metabolism, and contractility.

ZBTB20-mediated titanium particle-induced peri-implant osteolysis by promoting macrophage inflammatory responses

Aseptic loosening (AL) caused by wear particles released from implant surfaces is one of the main causes for the failure of artificial joints, which is initiated by macrophage inflammatory responses. Emerging evidence suggests that the member of a broad-complex, tramtrack, bric-a-brac/poxvirus and zinc finger (BTB/POZ) family as well as zinc finger and BTB domain-containing protein 20 (ZBTB20) can inhibit IκBα gene transcription, promote NF-κB activation, and initiate innate immune responses. The molecular mechanism(s) by which ZBTB20 contributes to titanium particle (TiP)-induced macrophage inflammatory responses and osteolysis has not been fully elucidated. Here, we showed that ZBTB20 increased either in the AL group's synovial membranes or in TiP-stimulated bone-marrow-derived macrophages (BMDMs) as compared to that in the control groups. Moreover, the knockdown of ZBTB20 led to the inhibition of proinflammatory factors induced by TiPs in BMDMs, such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interferon-β (IFN-β). Here, we also reported that the knockdown of ZBTB20 suppressed TiP-induced NF-κB activation and M1 polarization as well as stabilized the trans Golgi network (TGN) in BMDMs. The dual-luciferase reporter assay identified the binding between the IκBα promoter and ZBTB20, and IκBα knockdown could rescue the antiinflammatory effects induced by the ZBTB20 knockdown in BMDMs. Finally, we found that sh-ZBTB20 lentivirus injection could reduce TiP-induced osteolysis in mouse calvaria, inhibiting TiP-induced proinflammatory factors and loss of bone volume/total volume (BV/TV) as well as bone mineral density (BMD). These results suggest that ZBTB20 positively regulated NF-κB activation and M1 polarization as well as the production of TGN-derived tubular carriers in BMDMs, playing a positive role in macrophage activation and mouse cranial osteolysis induced by TiPs. It may be a potential therapeutic target for the prevention of aseptic loosening of prostheses.