CtBP1 overexpression in keratinocytes perturbs skin homeostasis

TOP2A Promotes Proliferation, Migration, and Inflammatory Response in M5-Treated Keratinocytes by Binding CTBP1 to Activate Wnt/β-Catenin Signaling

Psoriasis is a chronic cutaneous disease, affecting a significant portion of the global population. Topoisomerase II alpha (TOP2A) is upregulated in psoriasis samples, but the precise molecular mechanism remains unclear. We aimed to clarify the biological contribution of TOP2A in psoriasis progression. An in vitro psoriasis model was established on M5-induced keratinocytes (HaCaT cells) to simulate the psoriasis-like alterations. Following TOP2A knockdown without or with c terminal binding protein 1 (CTBP1) overexpression, CCK-8 and EDU staining were employed to analyze the viability and proliferation of HaCaT cells under M5 conditions. The capacities of HaCaT cell migration and invasion were examined with wound healing- and transwell assays. RT-qPCR and immunoblotting were adopted for evaluation of the inflammation and differentiation of M5-stimualted HaCaT cells. Additionally, the binding between TOP2A and CTBP1 was predicated using bioinformatics tools and detected by Co-IP. Finally, the expression of proteins in Wnt/β-catenin signaling was analyzed with the application of immunoblotting. Results suggested that TOP2A was upregulated in psoriasis skin lesions and M5-induced HaCaT cells. Interference with TOP2A attenuated the proliferation, migration, invasion, and inflammatory response in M5-treated HaCaT cells. In particular, TOP2A bound to CTBP1 and upregulated CTBP1 expression in HaCaT cells. Remarkably, CTBP1 upregulation blocked the impacts of TOP2A depletion on the biological behaviors of M5-treated HaCaT cells. Besides, TOP2A deficiency upregulated DKK1 expression as well as downregulated Wnt1, β-catenin, and c-Myc expression in HaCaT cells exposed to M5, which was restored by further CTBP1 overexpression. In summary, TOP2A binds CTBP1 to activate Wnt/β-catenin signaling, thereby promoting the progression of psoriasis.

CXXC5 function blockade promotes diabetic wound healing through stimulating fibroblast and vascular endothelial cell activation

BACKGROUND

Extracellular matrix (ECM) and angiogenesis are critical controls of wound regeneration, and their dysfunction delays diabetes recovery. CXXC5 belongs to the CXXC protein family that can regulate the function of human dermal fibroblasts (HDFs) and human umbilical vein endothelial cells (HUVECs); However, awareness of its functional role remains limited.

METHODS

Mice were divided into control (CON), diabetic (DM), diabetic + KY19382 (DM + KY19382), and diabetic + vehicle (DM + Vehicle) groups. HDFs and HUVECs were stimulated under different CXXC5 conditions and mice were treated with KY19382, followed by the application of assays including Western blotting (WB), immunofluorescence (IF) and quantitative reverse transcription-PCR (qRT-PCR) to assess wound healing and molecular signaling.

RESULTS

Mice in DM had fewer blood vessels, a slower wound healing rate, and more disrupted collagen than CON. Application of KY19382 improved these conditions, which promoted fibroblast activation and vascularization in high glucose environments and DM. Mechanistically, blocking CXXC5 promotes Wnt/β-catenin-mediated stabilization by reducing the binding of the deterrent factor CTBP1 to β-catenin, which induces dermal fibroblast activation and facilitates HUVECs tube formation and migration via VEGFA/VEGFR2 and NFκB signaling pathways. KY19382 promotes HUVECs activation by blocking CTBP1 transcription to activate the NFκB signaling pathway, thus wound re-vascularization.

CONCLUSION

CXXC5 is an essential regulatory factor of wound healing and a prospective therapeutic target for treating chronic wound damage in diabetes.

Inhibition of CtBP-Regulated Proinflammatory Gene Transcription Attenuates Psoriatic Skin Inflammation

Psoriasis is a chronic immune-mediated disease characterized by excessive proliferation of epidermal keratinocytes and increased immune cell infiltration to the skin. Although it is well-known that psoriasis pathogenesis is driven by aberrant production of proinflammatory cytokines, the mechanisms underlying the imbalance between proinflammatory and anti-inflammatory cytokine expression are incompletely understood. In this study, we report that the transcriptional coregulators CtBP1 and 2 can transactivate a common set of proinflammatory genes both in the skin of imiquimod-induced mouse psoriasis model and in human keratinocytes and macrophages stimulated by imiquimod. We find that mice overexpressing CtBP1 in epidermal keratinocytes display severe skin inflammation phenotypes with increased expression of T helper type 1 and T helper type 17 cytokines. We also find that the expression of CtBPs and CtBP-target genes is elevated both in human psoriatic lesions and in the mouse imiquimod psoriasis model. Moreover, we were able to show that topical treatment with a peptidic inhibitor of CtBP effectively suppresses the CtBP-regulated proinflammatory gene expression and thus attenuates psoriatic inflammation in the imiquimod mouse model. Together, our findings suggest to our knowledge previously unreported strategies for therapeutic modulation of the immune response in inflammatory skin diseases.

Non-Coding RNA in Systemic Sclerosis: A Valuable Tool for Translational and Personalized Medicine

Epigenetic factors are heritable and ultimately play a role in modulating gene expression and, thus, in regulating cell functions. Non-coding RNAs have growing recognition as novel biomarkers and crucial regulators of pathological conditions in humans. Their characteristic feature is being transcribed in a tissue-specific pattern. Now, there is emerging evidence that lncRNAs have been identified to be involved in the differentiation of human skin, wound healing, fibrosis, inflammation, and immunological response. Systemic sclerosis (SSc) is a heterogeneous autoimmune disease characterized by fibrosis, vascular abnormalities, and immune system activation. The pathogenesis remains elusive, but clinical manifestations reveal autoimmunity with the presence of specific autoantibodies, activation of innate and adaptive immunity, vascular changes, and active deposition of extracellular matrix components leading to fibrosis. The use of multi-omics studies, including NGS, RNA-seq, or GWAS, has proposed that the non-coding genome may be a significant player in its pathogenesis. Moreover, it may unravel new therapeutic targets in the future. The aim of this review is to show the pathogenic role of long non-coding RNAs in systemic sclerosis. Investigation of these transcripts' functions has the potential to elucidate the molecular pathology of SSc and provide new opportunities for drug-targeted therapy for this disorder.

Skin remodeling and wound healing in the Gottingen minipig following exposure to sulfur mustard

Sulfur mustard (SM), a dermal vesicant that has been used in chemical warfare, causes inflammation, edema and epidermal erosions depending on the dose and time following exposure. Herein, a minipig model was used to characterize wound healing following dermal exposure to SM. Saturated SM vapor caps were placed on the dorsal flanks of 3-month-old male Gottingen minipigs for 30 min. After 48 h the control and SM wounded sites were debrided daily for 7 days with wet to wet saline gauze soaks. Animals were then euthanized, and full thickness skin biopsies prepared for histology and immunohistochemistry. Control skin contained a well differentiated epidermis with a prominent stratum corneum. A well-developed eschar covered the skin of SM treated animals, however, the epidermis beneath the eschar displayed significant wound healing with a hyperplastic epidermis. Stratum corneum shedding and a multilayered basal epithelium consisting of cuboidal and columnar cells were also evident in the neoepidermis. Nuclear expression of proliferating cell nuclear antigen (PCNA) was contiguous in cells along the basal epidermal layer of control and SM exposed skin; SM caused a significant increase in PCNA expression in basal and suprabasal cells. SM exposure was also associated with marked changes in expression of markers of wound healing including increases in keratin 10, keratin 17 and loricrin and decreases in E-cadherin. Trichrome staining of control skin showed a well-developed collagen network with no delineation between the papillary and reticular dermis. Conversely, a major delineation was observed in SM-exposed skin including a web-like papillary dermis composed of filamentous extracellular matrix, and compact collagen fibrils in the lower reticular dermis. Although the dermis below the wound site was disrupted, there was substantive epidermal regeneration following SM-induced injury. Further studies analyzing the wound healing process in minipig skin will be important to provide a model to evaluate potential vesicant countermeasures.

CTBP1 Confers Protection for Hippocampal and Cortical Neurons in Rat Models of Alzheimer's Disease

OBJECTIVE

Alzheimer's disease (AD) is an age-related devastating neurodegenerative disorder. The hippocampus and cerebral cortex are the most closely related brain regions of cognitive function and neurogenesis. The present study investigated the role of C-terminal-binding protein 1 (CTBP1) in AD.

METHODS

AD rat models were established through intracerebroventricular injection of β-amyloid polypeptide Aβ(25-35) and intragastric administration of aluminum chloride solution, and the expression pattern that CTBP1 showed in the hippocampus and cerebral cortex was determined. The learning and memory abilities of AD rats after CTBP1 overexpression were assessed. Hippocampal and cortical neurons were transfected with siRNA against CTBP1 or CTBP1-overexpressing plasmids in order to study the effects of CTBP1 elevation or depletion on neuron morphological changes, apoptosis, and viability. The expression of CTBP1, proapoptotic factor (B-cell lymphoma 2; Bcl-2), and antiapoptotic factors (Bcl-2-associated X protein [Bax] and caspase-3) was subsequently evaluated.

RESULTS

CTBP1 was poorly expressed in the hippocampus and cerebral cortex. AD rats displayed enhanced learning and memory abilities following CTBP1 overexpression. Furthermore, overexpression of CTBP1 improved morphological changes of hippocampal and cortical neurons, increased neuron activity, and inhibited neuron apoptosis in AD rats. Moreover, the expression of Bax and caspase-3 decreased, yet Bcl-2 increased.

CONCLUSION

Collectively, CTBP1 plays a protective role in the degeneration of hippocampal and cortical neurons whereby overexpressed CTBP1 attenuated the hippocampal and cortical neuron apoptosis and enhanced neuron activity, highlighting the potential of CTBP1 as a target for AD treatment.

Antisense Long Non-Coding RNAs Are Deregulated in Skin Tissue of Patients with Systemic Sclerosis

Systemic sclerosis is an autoimmune disease characterized by fibrosis of skin and multiple organs of which the pathogenesis is poorly understood. We studied differentially expressed coding and non-coding genes in relation to systemic sclerosis pathogenesis with a specific focus on antisense non-coding RNAs. Skin biopsy-derived RNAs from 14 early systemic sclerosis patients and six healthy individuals were sequenced with ion-torrent and analyzed using DEseq2. Overall, 4,901 genes with a fold change >1.5 and a false discovery rate <5% were detected in patients versus controls. Upregulated genes clustered in immunologic, cell adhesion, and keratin-related processes. Interestingly, 676 deregulated non-coding genes were detected, 257 of which were classified as antisense genes. Sense genes expressed opposite of these antisense genes were also deregulated in 42% of the observed sense-antisense gene pairs. The majority of the antisense genes had a similar effect sizes in an independent North American dataset with three genes (CTBP1-AS2, OTUD6B-AS1, and AGAP2-AS1) exceeding the study-wide Bonferroni-corrected P-value (P_Bonf < 0.0023, P_combined = 1.1 × 10^-9, 1.4 × 10^-8, 1.7 × 10^-6, respectively). In this study, we highlight that together with coding genes, (antisense) long non-coding RNAs are deregulated in skin tissue of systemic sclerosis patients suggesting a novel class of genes involved in pathogenesis of systemic sclerosis.

Prostate tumor growth is impaired by CtBP1 depletion in high-fat diet-fed mice

PURPOSE

Clinical and epidemiologic data suggest that obesity is associated with more aggressive forms of prostate cancer, poor prognosis, and increased mortality. C-terminal-binding protein 1 (CtBP1) is a transcription repressor of tumor suppressor genes and is activated by NADH binding. High calorie intake decreases intracellular NAD(+)/NADH ratio. The aim of this work was to assess the effect of high-fat diet (HFD) and CtBP1 expression modulation over prostate xenograft growth.

EXPERIMENTAL DESIGN

We developed a metabolic syndrome-like disease in vivo model by feeding male nude mice with HFD during 16 weeks. Control diet (CD)-fed animals were maintained at the same conditions. Mice were inoculated with PC3 cells stable transfected with shCtBP1 or control plasmids. Genome-wide expression profiles and Gene Set Enrichment Analysis (GSEA) were performed from PC3.shCtBP1 versus PC3.pGIPZ HFD-fed mice tumors.

RESULTS

No significant differences were observed in tumor growth on CD-fed mice; however, we found that only 60% of HFD-fed mice inoculated with CtBP1-depleted cells developed a tumor. Moreover these tumors were significantly smaller than those generated by PC3.pGIPZ control xenografts. We found 823 genes differentially expressed in shCtBP1 tumors from HFD-fed mice. GSEA from expression dataset showed that most of these genes correspond to cell adhesion, metabolic process, and cell cycle.

CONCLUSIONS

Metabolic syndrome-like diseases and CtBP1 expression cooperate to induce prostate tumor growth. Hence, targeting of CtBP1 expression might be considered for prostate cancer management and therapy in the subset of patients with metabolic syndromes.