GATA6 is a crucial factor for Myocd expression in the visceral smooth muscle cell differentiation program of the murine ureter

Ureter development and associated congenital anomalies

Malformations of the ureter are among the most common birth defects in humans. Although some of these anomalies are asymptomatic, others are clinically relevant, causing perinatal lethality or progressing to kidney failure in childhood. The genetic causes and developmental aetiology of ureteral anomalies are difficult to study in humans; however, embryological and genetic analyses in the mouse have provided insights into the complex developmental programmes that govern ureter formation from simple tissue primordia, and the pathological consequences that result from disruption of these programmes. Abnormalities in the formation of the nephric duct and ureteric bud lead to changes in the number of ureters (and kidneys), whereas the formation of ectopic ureteric buds, failure of the nephric duct to target the cloaca or failure of the distal ureter to mature underlie vesicoureteral reflux, ureter ectopia, ureterocoele and subsequent hydroureter. Alterations in ureter specification, early growth or cyto-differentiation programmes have now also been associated with various forms of perinatal hydroureter and hydronephrosis as a consequence of functional obstruction. The characterization of cellular processes and molecular drivers of ureterogenesis in the mouse may not only aid understanding of the aetiology of human ureteral anomalies, improve prognostication and benefit the development of therapeutic strategies, but may also prove important for efforts to generate a bioartificial organ.

Interplay of SHH, WNT and BMP4 signaling regulates the development of the lamina propria in the murine ureter

In mammalian ureters, the lamina propria presents as a prominent layer of connective tissue underneath the urothelium. Despite its important structural and signaling functions, little is known how the lamina propria develops. Here, we show that in the murine ureter the lamina propria arises at late fetal stages and massively increases by fibrocyte proliferation and collagen deposition after birth. WNT, SHH, BMP4 and retinoic acid signaling are all active in the common mesenchymal progenitor of smooth muscle cells and lamina propria fibrocytes. However, around birth, the lamina propria becomes a target for epithelial WNT and SHH signals and a source of BMP4 and retinoic acid. SHH and WNT signaling promote lamina propria and smooth muscle cell differentiation and proliferation at fetal and early postnatal stages, whereas BMP4 signaling is required for early smooth muscle cell differentiation but not for its later maintenance. Our findings suggest that, in the presence of SHH and WNT signaling, it is the modulation of BMP4 signaling which is the major determinant for the segregation of lamina propria and smooth muscle cells.

Corpus cavernosum and tunica albuginea reconstruction by tissue engineering: towards functional erectile structures regeneration

BACKGROUND

Current treatments for penile erectile structures reconstruction are limited and remain a great challenge in clinical practice. Tissue engineering techniques using different seed cells and scaffolds to construct a neo-tissue open promising avenues for penile erectile structures repair and replacement and show great promise in the restoration of: structure, mechanical property, and function which matches the original tissue.

METHODS

A comprehensive literature review was conducted by accessing the NCBI PubMed, Cochrane, and Google Scholar databases from January 1, 1990, to January, 1, 2022 using the search terms "Tissue engineering, Corpus cavernosum (CC), Tunica albuginea (TA), Acellular Matrix, Penile Reconstruction". Articles were screened and assessed by two independent reviewers to determine whether those met the inclusion criteria, and a total of 19 articles were being selected and included in the data analysis.

RESULTS

Tissue engineered cell-seeded scaffold can reconstruct a similar structure to native TA and CC and showed good histocompatibility with no immunological rejection. The results of the evaluation of morphological feature, intracavernosal pressure, and erectile-related nitric oxide (NO) expression were strongly proofs that the tissue engineered graft can significantly improve the penile erectile and ejaculatory function. In addition, increasing the purity of seed cells, improving the mechanical properties of the scaffold, providing appropriate induction for stem cells, and optimizing cell delivery systems are potential approaches to improve reconstructive outcomes. Currently, a larger animal model, comparable in size to the human penis, is needed to test the feasibility of the engineered grafts.

CONCLUSION

Our review summarized the research in tissue engineering of CC and TA. It showed great promise in reconstructing the functional structures and restoring the erection and ejaculatory function. With continuous advancement in the field, tissue-engineered penile erectile structures hold substantial potential to enhance clinical outcomes for patients.

SWI/SNF Complex in Vascular Smooth Muscle Cells and Its Implications in Cardiovascular Pathologies

Mature vascular smooth muscle cells (VSMC) exhibit a remarkable degree of plasticity, a characteristic that has intrigued cardiovascular researchers for decades. Recently, it has become increasingly evident that the chromatin remodeler SWItch/Sucrose Non-Fermentable (SWI/SNF) complex plays a pivotal role in orchestrating chromatin conformation, which is critical for gene regulation. In this review, we provide a summary of research related to the involvement of the SWI/SNF complexes in VSMC and cardiovascular diseases (CVD), integrating these discoveries into the current landscape of epigenetic and transcriptional regulation in VSMC. These novel discoveries shed light on our understanding of VSMC biology and pave the way for developing innovative therapeutic strategies in CVD treatment.

Smooth Muscle Heterogeneity and Plasticity in Health and Aortic Aneurysmal Disease

Vascular smooth muscle cells (VSMCs) are the predominant cell type in the medial layer of the aorta, which plays a critical role in the maintenance of aortic wall integrity. VSMCs have been suggested to have contractile and synthetic phenotypes and undergo phenotypic switching to contribute to the deteriorating aortic wall structure. Recently, the unprecedented heterogeneity and diversity of VSMCs and their complex relationship to aortic aneurysms (AAs) have been revealed by high-resolution research methods, such as lineage tracing and single-cell RNA sequencing. The aortic wall consists of VSMCs from different embryonic origins that respond unevenly to genetic defects that directly or indirectly regulate VSMC contractile phenotype. This difference predisposes to hereditary AAs in the aortic root and ascending aorta. Several VSMC phenotypes with different functions, for example, secreting VSMCs, proliferative VSMCs, mesenchymal stem cell-like VSMCs, immune-related VSMCs, proinflammatory VSMCs, senescent VSMCs, and stressed VSMCs are identified in non-hereditary AAs. The transformation of VSMCs into different phenotypes is an adaptive response to deleterious stimuli but can also trigger pathological remodeling that exacerbates the pathogenesis and development of AAs. This review is intended to contribute to the understanding of VSMC diversity in health and aneurysmal diseases. Papers that give an update on VSMC phenotype diversity in health and aneurysmal disease are summarized and recent insights on the role of VSMCs in AAs are discussed.

Transcription factor GATA6 promotes migration of human coronary artery smooth muscle cells in vitro

Vascular smooth muscle cell plasticity plays a pivotal role in the pathophysiology of vascular diseases. Despite compelling evidence demonstrating the importance of transcription factor GATA6 in vascular smooth muscle, the functional role of GATA6 remains poorly understood. The aim of this study was to elucidate the role of GATA6 on cell migration and to gain insight into GATA6-sensitive genes in smooth muscle. We found that overexpression of GATA6 promotes migration of human coronary artery smooth muscle cells in vitro, and that silencing of GATA6 in smooth muscle cells resulted in reduced cellular motility. Furthermore, a complete microarray screen of GATA6-sensitive gene transcription resulted in 739 upregulated and 248 downregulated genes. Pathways enrichment analysis showed involvement of transforming growth factor beta (TGF-β) signaling which was validated by measuring mRNA expression level of several members. Furthermore, master regulators prediction based on microarray data revealed several members of (mitogen activated protein kinase) MAPK pathway as a master regulators, reflecting involvement of MAPK pathway also. Our findings provide further insights into the functional role of GATA6 in vascular smooth muscle and suggest that targeting GATA6 may constitute as a new approach to inhibit vascular smooth muscle migration.