TGF-β1-induced connexin43 promotes scar formation via the Erk/MMP-1/collagen III pathway

Cell Junctions in Periodontal Health and Disease: An Insight

Cells are the building blocks of all living organisms. The presence of cell junctions such as tight junctions, gap junctions, and anchoring junctions between cells play a role in cell-to-cell communication in periodontal health and disease. A literature search was done in Scopus, PubMed, and Web of Science to gather information about the effect of cell junctions on periodontal health and disease. The presence of tight junction in the oral cavity helps in cell-to-cell adhesiveness and assists in the barrier function. The gap junctions help in controlling growth and development and in the cell signaling process. The presence of desmosomes and hemidesmosomes as anchoring junctions aid in mechanical strength and tissue integrity. Periodontitis is a biofilm-induced disease leading to the destruction of the supporting structures of the tooth. The structures of the periodontium possess multiple cell junctions that play a significant role in periodontal health and disease as well as periodontal tissue healing. This review article provides an insight into the role of cell junctions in periodontal disease and health, and offers concepts for development of therapeutic strategies through manipulation of cell junctions.

Single-Cell RNA-Sequencing Reveals the Cellular and Genetic Heterogeneity of Skin Scar to Verify the Therapeutic Effects and Mechanism of Action of Dispel-Scar Ointment in Hypertrophic Scar Inhibition

Hypertrophic scarring (HS), caused by excessive fibrosis of injured skin, imposes a psychological burden and creates a source of distress that impairs the quality of life of affected individuals. However, the gold standard for HS treatment has not yet been determined due to the complicated and difficult nature of the routines and procedures involved. Previous studies have indicated that the topical application of certain active components found in traditional Chinese medicines shows potential as a therapeutic alternative for scars. Here, single-cell RNA-sequencing was performed to determine cellular heterogeneity and identify marker genes and mechanisms associated with HS. It was found that fibroblasts comprise the largest proportion of HS cell types. The marker genes that were highly expressed in fibroblasts were extracellular matrix (ECM)-related, whereas ECM-receptor interactions and the transforming growth factor (TGF)-β signalling pathway were also found to be active. Ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry, which was applied to identify the molecular compounds of Dispel-Scar Ointment (DSO), revealed 74 effective chemical components belonging to 14 types of constituents, such as flavonoids, tanshinones, salvianolic acids, glycosides, and phthalides. Furthermore, in vivo studies using rat scar models showed that the topical application of Salvia miltiorrhiza, Ligusticum chuanxiong, peach kernel, safflower, and motherwort exerted beneficial effects on fibroblasts. DSO promoted scar maturation and reduced scar areas, its efficacy being similar to that of topically applied silicone. Functional studies using immunofluorescence staining, western blotting, and quantitative real-time polymerase chain reaction demonstrated that DSO may target the TGF-β/Smad pathway to inhibit collagen synthesis and promote ECM remodelling. However, further in vitro mechanistic research and single-drug prescription studies may be required to identify the specific effective compound or active ingredient of DSO, which would provide more substantial evidence regarding the potential therapeutic value of traditional herbs in HS.

Dynamics of Connexin 43 Down Modulation in Human Articular Chondrocytes Stimulated by Tumor Necrosis Factor Alpha

Connexin 43 (Cx43) exerts pivotal functions in articular chondrocytes (CH). It is involved in the communication among cells and between cells and the extracellular environment, and it contributes to the maintenance of the correct cell phenotype. The pro-inflammatory cytokine TNFα induces a reduction in Cx43 expression in CH. Here, we studied the dynamics of this decrease in expression. We evaluated Cx43 protein and gene expression and the involvement of C-terminal domain (CTD) cleavage and proteasomal degradation. Treatments able to counteract TNFα action were also examined, together with Gap Junction (GJ) functionality and Cx43 localization. TNFα induced a significant reduction in Cx43 expression already at day 1, and the down modulation reached a peak at day 3 (−46%). The decrease was linked to neither gene expression modulation nor CTD cleavage. Differently, the proteasome inhibitor MG132 reverted TNFα effect, indicating the involvement of proteasomal degradation in Cx43 reduction. In addition, the co-treatment with the anabolic factor TGF-β1 restored Cx43 levels. Cx43 decrease occurred both at the membrane level, where it partially influenced GJ communication, and in the nucleus. In conclusion, TNFα induced a rapid and lasting reduction in Cx43 expression mostly via the proteasome. The down modulation could be reverted by cartilage-protective factors such as MG132 and TGF-β1. These findings suggest a possible involvement of Cx43 perturbation during joint inflammation.

The role of extracellular matrix on unfavorable maternal–fetal interface: focusing on the function of collagen in human fertility

Extracellular matrix (ECM) is characterized as widespread, abundant, and pluripotent. Among ECM members, collagen is widely accepted as one of the most prominent components for its essential structural property that can provide a scaffold for other components of ECM and the rich biological functions, which has been extensively used in tissue engineering. Emerging evidence has shown that the balance of ECM degradation and remodeling is vital to regulations of maternal–fetal interface including menstrual cycling, decidualization, embryo implantation and pregnancy maintenance. Moreover, disorders in these events may eventually lead to failure of pregnancy. Although the improvement of assisted conception and embryo culture technologies bring hope to many infertile couples, some unfavorable outcomes, such as recurrent implantation failure (RIF), recurrent pregnancy loss (RPL) or recurrent miscarriage (RM), keep troubling the clinicians and patients. Recently, in vitro three-dimensional (3D) model mimicking the microenvironment of the maternal–fetal interface is developed to investigate the physiological and pathological conditions of conception and pregnancy. The progress of this technology is based on clarifying the role of ECM in the endometrium and the interaction between endometrium and conceptus. Focusing on collagen, the present review summarized the degradation and regulation of ECM and its role in normal menstruation, endometrium receptivity and unsatisfying events occurring in infertility treatments, as well as the application in therapeutic approaches to improve pregnancy outcomes. More investigations about ECM focusing on the maternal–fetal interface interaction with mesenchymal stem cells or local immunoregulation may inspire new thoughts and advancements in the clinical application of infertility treatments.

Graphical abstract

Orodispersible hyaluronic acid film delivery for oral wound healing in rats

Background/purpose

Oral wound healing undergoes a dynamic process of oral environment. This study aimed to investigate the effects of hyaluronic acid (HA) film on oral wound healing in a rat model.

Materials and methods

A total of 60 rats with tongue wounds (5 mm in diameter) were randomly divided into control (n = 20), HA gel (n = 20), and HA film groups (n = 20). The animals were sacrificed on either 3 or 7 days after the experiment. Clinical, histological, and quantitative reverse transcriptase-polymerase chain reaction analysis were performed to evaluate the healing rate, inflammation, re-epithelialization, and gene expression of wound healing biomarkers.

Results

The healing rates of HA gel (84.4 ± 9.2%) and HA film (74.0 ± 15.0%) were significantly higher than that of the control (51.7 ± 16.9%) on day 7 (P < 0.001 and P = 0.002, respectively). Histological analysis revealed no significant differences between the groups on day 3. On day 7, only the HA film showed significant improvement in inflammation (P = 0.038) and re-epithelialization (P = 0.011) compared to the control. Regarding wound healing biomarkers, both HA gel and HA film groups showed lower level of COL1α1 expression on day 3 compared to the control.

Conclusion

Within the limits of this study, HA film was found to be effective for oral wound healing, particularly for re-epithelialization. This finding suggests that HA film delivery can be beneficial not only for clinical convenience but also for promoting oral wound healing.

TGF-β1 and its signal molecules: are they correlated with the elasticity characteristics of breast lesions?

Background

Shear wave elastography can evaluate tissue stiffness. Previous studies showed that the elasticity characteristics of breast lesions were related to the components of extracellular matrix which was regulated by transforming growth factor beta 1(TGF-β1) directly or indirectly. However, the correlation of the expression level of TGF-β1, its signal molecules and elasticity characteristics of breast lesions have rarely been reported. The purpose of this study was to investigate the correlation between the expression level of TGF-β1, its signal molecules, and the elasticity characteristics of breast lesions.

Methods

135 breast lesions in 130 patients were included. Elasticity parameters, including elasticity modulus, the elasticity ratio, the “stiff rim sign”, were recorded before biopsy and surgical excision. The expression levels of TGF-β1 and its signal molecules, including Smad2/3, Erk1/2, p38 mitogen-activated protein kinase (MAPK), c-Jun N-terminal kinase 2 (JNK2), phosphoinositide 3-kinase (PI3K), and protein kinase B (PKB/AKT) were detected by immunohistochemistry. The diagnostic performance of the expression level of those molecules and their correlation with the elasticity characteristics were analyzed.

Results

Elasticity parameters and the expression levels of TGF- β1 and its signal molecules of benign lesions were lower than those of malignant lesions (P<0.0001). The expression levels of TGF- β1 and its signal molecules were correlated with elasticity parameters. The expression levels of TGF- β1 and its signal molecules in lesions with “stiff rim sign” were higher than those without “stiff rim sign” (P<0.05). And the expression levels of Smad2/3, Erk1/2, p38 MAPK, JNK2, PI3K and AKT were correlated with that of TGF- β1. The area under the curve for receiver operator characteristic curve of TGF-β1 and its signal molecules in the differentiation of malignant and benign breast lesions ranged from 0.920–0.960.

Conclusions

The expression levels of TGF-β1, its signal molecules of breast lesions showed good diagnostic performance and were correlated with the elasticity parameters. The expression levels of signal molecules were correlated with that of TGF- β1, which speculated that TGF- β1 might play an important role in the regulation of breast lesion elasticity parameters and multiple signal molecule expressions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-09036-4.

Gap junction-mediated cell-to-cell communication in oral development and oral diseases: a concise review of research progress

Homoeostasis depends on the close connection and intimate molecular exchange between extracellular, intracellular and intercellular networks. Intercellular communication is largely mediated by gap junctions (GJs), a type of specialized membrane contact composed of variable number of channels that enable direct communication between cells by allowing small molecules to pass directly into the cytoplasm of neighbouring cells. Although considerable evidence indicates that gap junctions contribute to the functions of many organs, such as the bone, intestine, kidney, heart, brain and nerve, less is known about their role in oral development and disease. In this review, the current progress in understanding the background of connexins and the functions of gap junctions in oral development and diseases is discussed. The homoeostasis of tooth and periodontal tissues, normal tooth and maxillofacial development, saliva secretion and the integrity of the oral mucosa depend on the proper function of gap junctions. Knowledge of this pattern of cell-cell communication is required for a better understanding of oral diseases. With the ever-increasing understanding of connexins in oral diseases, therapeutic strategies could be developed to target these membrane channels in various oral diseases and maxillofacial dysplasia.

Scars or Regeneration?-Dermal Fibroblasts as Drivers of Diverse Skin Wound Responses

Scarring and regeneration are two physiologically opposite endpoints to skin injuries, with mammals, including humans, typically healing wounds with fibrotic scars. We aim to provide an updated review on fibroblast heterogeneity as determinants of the scarring-regeneration continuum. We discuss fibroblast-centric mechanisms that dictate scarring-regeneration continua with a focus on intercellular and cell-matrix adhesion. Improved understanding of fibroblast lineage-specific mechanisms and how they determine scar severity will ultimately allow for the development of antiscarring therapies and the promotion of tissue regeneration.

Connexin 43 Mutations Lead to Increased Hemichannel Functionality in Skin Disease

Gap junctional channels are specialized components of the cellular membrane that allow the intercellular passage of small metabolites, ions, and second messengers to maintain homeostasis. They are comprised of members of the connexin gene family that encode a wide array of proteins that are expressed in nearly every tissue type. Cx43 is perceived to be the most broadly expressed connexin in humans, with several genetic skin diseases being linked to Cx43 mutations specifically. These mutations, in large, produce a gain of functional hemichannels that contribute to the phenotypes of Erythrokeratoderma Variabilis et Progressiva (EKVP), Palmoplantar Keratodemra Congenital Alopecia-1 (PPKCA1), and others that produce large conductance and increased permselectivity in otherwise quiescent structures. Gaining functional hemichannels can have adverse effects in the skin, inducing apoptosis via Ca²⁺ overload or increased ATP permeability. Here, we review the link between Cx43 and skin disease. We aim to provide insight into the mechanisms regulating the normal and pathophysiological gating of these essential proteins, as well as address current therapeutic strategies. We also demonstrate that transient transfection of neuro-2a (N2a) cells with mutant Cx43 cDNA resulted in increased hemichannel activity compared to wild-type Cx43 and untransfected cells, which is consistent with other studies in the current literature.