The rhythms of histones in regeneration: The epigenetic modifications determined by clock genes.

The evolutionary establishment of an internal biological clock is a primordial event tightly associated with a 24-h period. Changes in the circadian rhythm can affect cellular functions, including proliferation, DNA repair and redox state. Even isolated organs, tissues and cells can maintain an autonomous circadian rhythm. These cell-autonomous molecular mechanisms are driven by intracellular clock genes, such as BMAL1. Little is known about the role of core clock genes and epigenetic modifications in the skin. Our focus was to identify BMAL1-driven epigenetic modifications associated with gene transcription by mapping the acetylation landscape of histones in epithelial cells responding to injury. We explored the role of BMAL1 in epidermal wound and tissue regeneration using a loss-of-function approach in vivo. We worked with BMAL1 knockout mice and a contraction-resistance wound healing protocol, determining the histone modifications using specific antibodies to detect the acetylation levels of histones H3 and H4. We found significant differences in the acetylation levels of histones in both homeostatic and injured skin with deregulated BMAL1. The intact skin displayed varied acetylation levels of histones H3 and H4, including hyperacetylation of H3 Lys 9 (H3K9). The most pronounced changes were observed at the repair site, with notable alterations in the acetylation pattern of histone H4. These findings reveal the importance of histone modifications in response to injury and indicate that modulation of BMAL1 and its associated epigenetic events could be therapeutically harnessed to improve skin regeneration.

Skin wound healing triggers epigenetic modifications of histone H4.

BACKGROUND: The skin is the largest organ of the human body. Upon injury, the skin triggers a sequence of signaling pathways that induce epithelial proliferation, migration, and ultimately, the re-establishment of the epithelial barrier. Our study explores the unknown epigenetic regulations of wound healing from a histone perspective. Posttranslational modifications of histones enhance chromatin accessibility and modify gene transcription. METHODS: Full-thickness wounds were made in the dorsal skin of twenty-four C57/B6 mice (C57BL/6J), followed by the use of ring-shaped silicone splints to prevent wound contraction. Tissue samples were collected at three time points (post-operatory day 1, 4, and 9), and processed for histology. Immunofluorescence was performed in all-time points using markers for histone H4 acetylation at lysines K5, K8, K12, and K16. RESULTS: We found well-defined histone modifications associated with the stages of healing. Most exciting, we showed that the epidermis located at a distance from the wound demonstrated changes in histone acetylation, particularly the deacetylation of histone H4K5, H4K8, and H4K16, and hyperacetylation of H4K12. The epidermis adjacent to the wound revealed the deacetylation of H4K5 and H4K8 and hyperacetylation of H4K12. Conversely, the migratory epithelium (epithelial tongue) displayed significant acetylation of H4K5 and H4K12. The H4K5 and H4K8 were decreased in the newly formed epidermis, which continued to display high levels of H4K12 and H4K16. CONCLUSIONS: This study profiles the changes in histone H4 acetylation in response to injury. In addition to the epigenetic changes found in the healing tissue, these changes also took place in tissues adjacent and distant to the wound. Furthermore, not only deacetylation but also hyperacetylation occurred during tissue repair and regeneration.

BMAL1 Modulates Epidermal Healing in a Process Involving the Antioxidative Defense Mechanism.

The circadian rhythm regulates the physiology and behavior of living organisms in a time-dependent manner. Clock genes have distinct roles including the control over gene expression mediated by the transcriptional activators CLOCK and BMAL1, and the suppression of gene expression mediated by the transcriptional repressors PER1/2 and CRY1/2. The balance between gene expression and repression is key to the maintenance of tissue homeostasis that is disrupted in the event of an injury. In the skin, a compromised epithelial barrier triggers a cascade of events that culminate in the mobilization of epithelial cells and stem cells. Recruited epithelial cells migrate towards the wound and reestablish the protective epithelial layer of the skin. Although we have recently demonstrated the involvement of BMAL and the PI3K signaling in wound healing, the role of the circadian clock genes in tissue repair remains poorly understood. Here, we sought to understand the role of BMAL1 on skin healing in response to injury. We found that genetic depletion of BMAL1 resulted in delayed healing of the skin as compared to wild-type control mice. Furthermore, we found that loss of Bmal1 was associated with the accumulation of Reactive Oxygen Species Modulator 1 (ROMO1), a protein responsible for inducing the production of intracellular reactive oxygen species (ROS). The slow healing was associated with ROS and superoxide dismutase (SOD) production, and pharmacological inhibition of the oxidative stress signaling (ROS/SOD) led to cellular proliferation, upregulation of Sirtuin 1 (SIRT1), and rescued the skin healing phenotype of Bmal1-/- mice. Overall, our study points to BMAL1 as a key player in tissue regeneration and as a critical regulator of ROMO1 and oxidative stress in the skin.

Low-temperature plasma on peri-implant-related biofilm and gingival tissue.

BACKGROUND: Evaluate the effect of low-temperature plasma (LTP) on an anaerobic biofilm and on the biological response of an in vitro reconstituted gingival epithelium tissue. METHODS: Porphyromonas gingivalis W83 biofilm was cultured on titanium discs and reconstituted gingival tissues were submitted to similar treatment conditions. TREATMENTS: LTP1-plasma treatment for 1 minute, LTP3-plasma treatment for 3 minute, CHX-0.2% chlorhexidine for 1 minute, GAS-gas only (no plasma) for 3 minute, and NEGATIVE-no treatment. TRITON group was included as a positive control for tissue analysis. Counting of viable colony forming units (CFU/mL) and confocal laser scanning microscopy were performed to evaluate LTP's antimicrobial effect. EpiGingival tissue was evaluated through cytotoxocity, viability, histology, and imunnohistochemistry (Ki67, vascular endothelial growth factor-A vascular endothelial growth factor A [VEGF-A], and terminal deoxynucleotidyl transferase dUTP nick end labeling terminal deoxynucleotidyl transferase dutp nick end labeling [TUNEL] expression). RESULTS: LTP1 and LTP3 presented significantly different reduced CFU/mL reduction in comparison to the negative control (Ρ < 0.001), but it was not as effective as the positive control (CHX). Low cytotoxicity and high viability were observed in gingival epithelium of NEGATIVE, GAS, CHX, and both LTP groups. The morphologic analysis of gingival epithelium revealed minor cell damage in the plasma groups (score 1). LTP1, LTP3, GAS, and NEGATIVE groups exhibited less than 5% of basal layer positive cells. LTP1, LTP3, GAS, and CHX groups were not positive for TUNEL assay. LTP1 and LTP3 showed the most positivity for VEGF. CONCLUSIONS: LTP treatment can be considered as an effective method for reducing P. gingivalis biofilm on implant surfaces, while being safe for the gingival epithelium. Furthermore, plasma treatment may be associated with cell repair.

Aggressive ameloblastic fibrosarcoma in maxilla: case report and new perspectives based on the current literature / Fibrossarcoma ameloblástico agressivo em maxila: relato de caso e novas perspectivas com base na literatura atual

ABSTRACT Ameloblastic fibrosarcoma (AFS) is a rare malignant tumor characterized by benign epithelial component within a malignant fibrous stroma. It occurs as a de novo lesion or from a previous ameloblastic fibroma. The aim of this paper is to report an aggressive and recurrent case of AFS in the maxilla of a 38-year-old patient. Histopathological diagnosis can be challenging, especially when it is based on incisional biopsy specimens. Hence, this report highlights not only the importance of the histological features for diagnosis but also the clinical behavior of AFS based on current literature evidence.

RESUMO O fibrossarcoma ameloblástico (FSA) é um tumor maligno raro caracterizado pela presença de componente epitelial benigno em um tecido conjuntivo fibroso maligno. Pode desenvolver-se a partir de um fibroma ameloblástico ou como uma lesão nova. O objetivo deste estudo é relatar um caso de um FSA agressivo e recorrente em maxila em um paciente de 38 anos. O diagnóstico histopatológico desse tumor pode ser difícil, principalmente a partir de biópsias incisionais. Este trabalho também discute fatores em relação aos aspectos histopatológicos para o seu diagnóstico, assim como seu comportamento clínico, com base em revisão atual da literatura.

Evaluation of hypoxia, angiogenesis, and lymphangiogenesis in actinic cheilitis.

BACKGROUND: Actinic cheilitis is a potentially malignant condition caused mainly by chronic sun exposure. Here we aim to evaluate the role of hypoxia, angiogenesis, and lymphatic density in the clinical and morphological progression of a series of cases of actinic cheilitis. MATERIALS AND METHODS: Immunohistochemistry was used to evaluate positivity to hypoxia-inducible factor (HIF)-1α, vascular endothelial growth factor (VEGF)-C, and D2-40 in 40 cases of actinic cheilitis of the lower lip. RESULTS: The cases studied exhibited variable degrees of positivity to the markers. The median number of lymphatic vessels was 3.2, 2.4, and 3.0 in lesions showing no epithelial dysplasia (NED) and with mild (MED) and moderate (MOED) epithelial dysplasia, respectively. The median VEGF-C positivity index was 82.44% (NED), 92.74% (MED), and 82.83% (MOED), and the median HIF-1α positivity index was 11.57% (NED), 5.26% (MED), and 13.55% (MOED). No significant differences in lymphatic density or median VEGF-C and HIF-1α positivity indices were observed between histological grades or clinical presentations of actinic cheilitis (P > 0.05). CONCLUSIONS: Although representing early events in lip carcinogenesis, the present results suggest that hypoxia, angiogenesis, and lymphangiogenesis do not influence the morphological or clinical progression of actinic cheilitis.

Anti-inflammatory effects of methanolic extract of green algae Caulerpa mexicana in a murine model of ulcerative colitis

Abstract Inflammatory bowel diseases, which include Crohn's disease and ulcerative colitis, are characterized by chronic and relapsed gut inflammation. Caulerpa mexicana is a type of green marine algae that can be found in tropical areas, such as the Brazilian Coastland. These macrophytes exhibit in vitro and in vivo anti-inflammatory properties such as the ability to reduce both cell migration to different sites and edema formation induced by chemical irritants. The aim of this study was to examine the effect of the C. mexicana methanolic extract on the treatment of colitis induced by dextran sodium sulfate. Acute experimental colitis was induced in BALB/c mice by treatment with 3% dextran sodium sulfate orally for 14 days. During this 14-day period, C. mexicana methanolic extract (2 mg/kg/day) was given intravenously on alternate days. Treatment with the methanolic extract significantly attenuated body weight loss and severe clinical symptoms. This was associated with a remarkable amelioration of colonic architecture disruption and a significant reduction in pro-inflammatory cytokine production. These results suggest that the anti-inflammatory action of C. mexicana methanolic extract on colorectal sites may be a useful therapeutic approach for inflammatory bowel diseases.

Immunoexpression of Th17-related cytokines in oral lichen planus.

A recently described lineage of lymphocytes, Th17 cells, has been associated with inflammatory and autoimmune diseases. The aim of this article was to assess the immunoexpression of cytokines related to this lineage, interleukin-17 (IL-17) and IL-23 and in reticular and erosive oral lichen planus (OLP). The sample included 41 cases of OLP (23 reticular and 18 erosive) and 10 cases of inflammatory fibrous hyperplasia (IFH). Lymphocytes exhibiting cytoplasmic immunostaining were counted. Epithelial immunostaining was also evaluated. There was no statistical differences in the number of IL-17 and IL-23 lymphocytes between the OLP (55.40 and 48.40, respectively) and IFH (39.30 and 44.40, respectively). A significantly higher number of IL-23 lymphocytes was found in erosive OLP group (63.80) when compared with reticular (41.40) and IFH lesions (44.40) (P=0.019). Furthermore, epithelial immunopositivity for IL-17 and IL-23 was higher in OLP lesions than in IFH (P=0.012 and P=0.011, respectively). A significantly higher number of IL-23 lymphocytes in erosive OLP and the strong epithelial immunopositivity for IL-23 and IL-17 in OLP group could suggest an important participation of TCD4 Th17 response in this disorder.

Factors associated with clinical characteristics and symptoms in a case series of oral lichen planus.

BACKGROUND: Oral lichen planus (OLP) is a relatively common chronic inflammatory disease whose etiopathogenesis is not completely understood. Several factors have been proposed in an attempt to explain the variety of clinical manifestations and periods of exacerbation and remission of symptoms of these lesions. The objective of this study was to associate local factors, systemic diseases, and level of anxiety with clinical characteristics of OLP. METHODS: The following factors were analyzed in 37 patients with OLP: presence of smoking, alcohol consumption, diabetes mellitus, hypertension, and hepatitis C virus infection. Anxiety was measured by the Spielberger State-Trait Anxiety Inventory. These variables were associated with clinical form and symptoms (chi-squared/Fisher's exact test). RESULTS: The erosive form was the most prevalent presentation (57.1%). Symptoms were reported by 45.7% of the patients. Most patients were non-smokers (97.3%), and none of them was an alcoholic. Diabetes and hypertension were present in 10.8% and 16.2% of the patients, respectively. Only one patient was hepatitis C virus seropositive, and 78.4% presented moderate levels of anxiety. No significant association was observed between the variables studied and clinical form or symptoms. CONCLUSIONS: In this study, no association was observed between local and systemic factors or level of anxiety and clinical characteristics of OLP.

Significance of galectins-1, -3, -4 and -7 in the progression of squamous cell carcinoma of the tongue.

The aim of this study was to analyze the immunohistochemical expression of galectins-1, -3, -4, and -7 in 65 cases of squamous cell carcinoma of the tongue and to correlate this expression with clinical (disease outcome, metastasis, and clinical stage) and morphological parameters (histological grade of malignancy). Clinical data were obtained from the patient records. The histological grading system of malignancy proposed by Bryne (1998) [9] was used for the analysis of morphological parameters. The results were analyzed statistically by χ(2) test (p < 0.05). Galectin-1 expression was observed in 87.7% of cases and was significantly correlated with metastasis (p = 0.033) and clinical stage (p = 0.016). Immunoexpression of galectin-3 was observed in 87.7% of cases and was correlated with the presence of metastasis (p = 0.033) and histological grade of malignancy (p = 0.031). Galectin-4 showed no significant correlation with any of the parameters studied. Expression of galectin-7 was observed in 73.8% of cases and was significantly correlated with the histological grade of malignancy (p = 0.005). In conclusion, the intense immunoexpression of galectins-1, -3, and -7 suggests the participation of these proteins in oral carcinogenesis and their use as markers of biological behavior and tumor progression in squamous cell carcinoma of the tongue.

Assessment of angiogenic markers in oral hemangiomas and pyogenic granulomas.

The purpose of this research was to evaluate the immunohistochemical expression of the vascular endothelial growth factor (VEGF-C1) and measuring the angiogenic activity by the staining for von Willebrand factor (vWF) and CD31 in oral pyogenic granulomas and hemangiomas. The results showed that there was no statistically significant difference in the angiogenesis index between the lesions evaluated. The average microvessel density determined for MVC (microvessel count) using CD31 was 60.64 for hemangiomas and 59.64 for pyogenic granulomas, while angiogenic index determined using vWF was 64.24 and 62.20 in these lesions. The results showed that the cells highlighted by staining for vWF were more uniform than in those stained for CD31. There was no statistically significant difference between the lesions for the number of cells highlighted by staining for VEGF-C1. However, the mean number of cells highlighted in pyogenic granuloma specimens was higher (153.23) when compared to oral hemangioma specimens (115.17). The VEGF-positive cells were endothelial cells and fibroblasts in hemangiomas and macrophages and fibroblasts in pyogenic granulomas. These results effort the role of the angiogenic factors in the etiopathogenesis of the hemangiomas and pyogenic granulomas, however, it showed that microvessel quantification is not useful in the differential diagnosis of these lesions.

O papel das proteínas da matriz extracelular e das metaloproteinases em carcinomas de cabeca e pescoco: uma atualizacão bibliográfica / The role of matrix extracellular proteins and metalloproteinases in head and neck carcinomas: an updated review

Interacões entre células neoplásicas e constituintes da matriz extracelular (MEC) interferem fortemente no desenvolvimento tumoral, incluindo os localizados em cabeca e pescoco, pois influenciam a proliferacão e sobrevivência celular, bem como a sua capacidade de migrar do sítio primário para outros tecidos e formar metástases. Essa migracão celular é facilitada pela destruicão parcial da MEC, a qual é realizada pelas metaloproteinases (MMPs), que representam uma família de mais de vinte endopeptidases, com atividade controlada pela expressão de inibidores específicos (TIMPs). Diversos estudos utilizando-se de marcadores para constituintes da MEC bem como pelas MMPs têm fornecido informacões adicionais sobre o diagnóstico e prognóstico em carcinomas de cabeca e pescoco. Nesta revisão consideraremos o papel da MEC e das MMPs na progressão desses tumores, enfatizando que não somente a degradacão proteolítica está envolvida neste processo, como também interacões entre vários constituintes da MEC fornecem substrato para regulacão e crescimento destes tumores.

The role of matrix extracellular proteins and metalloproteinases in head and neck carcinomas: an updated review.

Interactions involving tumor cells and the extracellular matrix (ECM) strongly influence tumor development, including head and neck tumors, affecting cell proliferation and survival as well as the ability to migrate beyond the original location into other tissues to form metastases. These cell migration is often facilitated by partial destruction of the surrounding ECM, which is catalyzed by matrix metalloproteinases (MMPs), a family of more than 20 endopeptidases that is controlled by regulated expression of specific inhibitors (TIMPs). Several studies of ECM and MMPs markers have provided additional diagnostic and prognostic information in head and neck carcinomas. In this review, we are considering the role of ECM and MMPs in tumor progression, emphasizing its proteolytic contributors to this process, and interactions between several members of ECM providing substrate to regulation of this process.