The Contribution of Mast Cells to the Regulation of Elastic Fiber Tensometry in the Skin Dermis of Children with Marfan Syndrome.

Marfan syndrome (MFS) is a hereditary condition accompanied by disorders in the structural and regulatory properties of connective tissue, including elastic fibers, due to a mutation in the gene encodes for fibrillin-1 protein (FBN1 gene) and the synthesis of abnormal fibrillin-1 glycoprotein. Despite the high potential of mast cells (MCs) to remodel the extracellular matrix (ECM), their pathogenetic significance in MFS has not been considered yet. The group of patients with Marfan syndrome included two mothers and five children (three girls aged 4, 11, and 11 and two boys aged 12 and 13). Normal skin was examined in two children aged 11 and 12. Histochemical, monoplex, and multiplex immunohistochemical techniques; combined protocols of simultaneous histochemical and immunohistochemical staining (the results of staining were assessed using light, epifluorescence, and confocal microscopy); and bioinformatics algorithms for the quantitative analysis of detected targets were used to evaluate mast cells and their relationship with other cells from extracellular structures in the skin dermis. Analysis of the skin MC population in children with Marfan syndrome revealed a considerably increased number of intra-organic populations with the preservation of the specific Tryptase+Chymase+CPA3+ protease profile typical of the skin. The features of the MC histotopography phenotype in MFS consisted of closer colocalization with elastic fibers, smooth muscle cells, and fibroblasts. MCs formed many intradermal clusters that synchronized the activity of cell functions in the stromal landscape of the tissue microenvironment with the help of spatial architectonics, including the formation of cell chains and the creation of fibrous niches. In MCs, the expression of specific proteases, TGF-ß, and heparin increased, with targeted secretion of biologically active substances relative to the dermal elastic fibers, which had specific structural features in MFS, including abnormal variability in thickness along their entire length, alternating thickened and thinned areas, and uneven surface topography. This paper discusses the potential role of MCs in strain analysis (tensometry) of the tissue microenvironment in MFS. Thus, the quantitative and qualitative rearrangements of the skin MC population in MFS are aimed at altering the stromal landscape of the connective tissue. The results obtained should be taken into account when managing clinical signs of MFS manifested in other pathogenetically critical structures of internal organs, including the aorta, tendons, cartilage, and parenchymal organs.

Mitochondrial DNA Mutations in Colorectal Cancer Stem Cells: Implications for Tumor Dynamics and Therapeutic Strategies.

This review offers an in-depth analysis of mitochondrial DNA (mtDNA) mutations in colorectal cancer stem cells (CSCs), emphasizing their significant impact on tumor dynamics and potential therapeutic strategies. CSCs are a special subpopulation due to their unique capabilities for self-renewal, differentiation, and resistance to conventional therapies. Given that CSCs significantly differ from other tumor cell subpopulations, particularly in their metabolic properties, and considering that colorectal cancer is a malignancy characterized by mitochondrial dysfunction, this review aims to put together existing data on the differences in the mitochondrial genome of CSCs compared to other colorectal tumor cell subpopulations. Additionally, the review seeks to explore the potential roles of these differences and to identify new ideas for therapeutic strategies. Key topics include the identification and properties of CSCs in colorectal cancer, the distinctive features of the mitochondrial genome, and the functional consequences of mtDNA mutations. The review hypothesizes that CSCs rely on well-functioning mitochondria for crucial aspects like energy production; yet, mtDNA mutations can lead to mitochondrial dysfunction, altering CSC characteristics and influencing cancer progression. The article discusses emerging therapeutic approaches targeting mitochondrial function in colorectal CSCs and highlights the need for advanced research, including the development of preclinical models and exploration of targeted therapies, to improve the understanding and treatment of colorectal cancer.

Renal Mast Cell-Specific Proteases in the Pathogenesis of Tubulointerstitial Fibrosis.

Chronic kidney disease is detected in 8-15% of the world's population. Along with fibrotic changes, it can lead to a complete loss of organ function. Therefore, a better understanding of the onset of the pathological process is required. To address this issue, we examined the interaction between mast cells (MCs) and cells in fibrous and intact regions, focusing on the role of MC proteases such as tryptase, chymase, and carboxypeptidase A3 (CPA3). MCs appear to be involved in the development of inflammatory and fibrotic changes through the targeted secretion of tryptase, chymase, and CPA3 to the vascular endothelium, nephron epithelium, interstitial cells, and components of intercellular substances. Protease-based phenotyping of renal MCs showed that tryptase-positive MCs were the most common phenotype at all anatomic sites. The infiltration of MC in different anatomic sites of the kidney with an associated release of protease content was accompanied by a loss of contact between the epithelium and the basement membrane, indicating the active participation of MCs in the formation and development of fibrogenic niches in the kidney. These findings may contribute to the development of novel strategies for the treatment of tubulointerstitial fibrosis.

Cyto- and Histopographic Assessment of CPA3-Positive Testicular Mast Cells in Obstructive and Non-Obstructive Azoospermia.

Infertility is an important personal and society disease, of which the male factor represents half of all causes. One of the aspects less studied in male infertility is the immunological testicular microenvironment. Mast cells (MCs), having high potential for regulating spermatogenesis due to fine-tuning the state of the integrative buffer metabolic environment, are one of the most crucial cellular subpopulations of the testicular interstitium. One important component of the MC secretome is proteases that can act as proinflammatory agents and in extracellular matrix (ECM) remodeling. In the testis, MCs are an important cell component of the testicular interstitial tissue (TIT). However, there are still no studies addressing the analysis of a specific MC protease-carboxypeptidase A3 (CPA3)-in cases with altered spermatogenesis. The cytological and histotopographic features of testicular CPA3+ MCs were examined in a study involving 34 men with azoospermia. As revealed, in cases with non-obstructive azoospermia, a higher content of CPA3+ MCs in the TIT and migration to the microvasculature and peritubular tissue of seminiferous tubules were observed when compared with cases with obstructive azoospermia. Additionally, a high frequency of CPA3+ MCs colocalization with fibroblasts, Leydig cells, and elastic fibers was detected in cases with NOA. Thus, CPA3 seems to be of crucial pathogenetic significance in the formation of a profibrogenic background of the tissue microenvironment, which may have direct and indirect effects on spermatogenesis.

Initial Characterization of a Transgenic Mouse with Overexpression of the Human H1-Histamine Receptor on the Heart.

There is a debate on whether H1-histamine receptors can alter contractility in the mammalian heart. We studied here a new transgenic mouse model where we increased genetically the cardiac level of the H1-histamine receptor. We wanted to know if histamine could augment or decrease contractile parameters in mice with cardiac-specific overexpression of human H1-histamine receptors (H1-TG) and compared these findings with those in littermate wild-type mice (WT). In H1-TG mice, we studied the presence of H1-histamine receptors by autoradiography of the atrium and ventricle using [3H]mepyramine. The messenger RNA for human H1-histamine receptors was present in the heart from H1-TG and absent from WT. Using in situ hybridization, we noted mRNA for the human H1-histamine receptor in cardiac cells from H1-TG. We noted that histamine (1 nM-10 µM) in paced (1 Hz) left atrial preparations from H1-TG, exerted at each concentration of histamine initially reduced force of contraction and then raised contractile force. Likewise, in spontaneously beating left atrial preparations from H1-TG, we noted that histamine led to a transient reduction in the spontaneous beating rate followed by an augmentation in the beating rate. The negative inotropic and chronotropic and the positive inotropic effects on histamine in isolated atrial muscle strips from H1-TG were attenuated by the H1-histamine receptor antagonist mepyramine. Histamine failed to exert an increased force or reduce the heartbeat in atrial preparations from WT. We concluded that stimulation of H1-histamine-receptors can decrease and then augment contractile force in the mammalian heart and stimulation of H1-histamine receptors exerts a negative chronotropic effect. SIGNIFICANCE STATEMENT: We made novel transgenic mice with cardiomyocyte-specific high expressional levels of the human H1-histamine receptor to contribute to the clarification of the controversy on whether H1-histamine receptors increase or decrease contractility and beating rate in the mammalian heart. From our data, we conclude that stimulation of H1-histamine receptors first decrease and then raise contractile force in the mammalian heart but exert solely negative chronotropic effects.

Ultrastructural features of tumor-associated mast cells in parasympathetic paragangliomas (chemodectomas) of the neck.

The mechanisms of the pathogenesis of neck paraganglioma (PGL) and the possible role of mast cells (MCs) in its development and metastasis are still poorly understood. We analyzed MCs' morphologic characterization, activation, and the properties of their cytoplasmic/released granules in PGLs, using light and transmission electron microscopy. Paragangliomas showed a large tumor-associated MC population both in the connective tissue layers of the tumor and between the tumor cells. Notably, MCs were presented by a high expression of specific proteases, size variation, polymorphism, and variable ultrastructural phenotype of granules. A massive number of granules were released surrounding the degranulated MCs while the integrity of MC membrane was maintained. Granules were electron-dense with or without a membrane, ranging from 0.2 to 0.8 µm in diameter. MC plasmalemma was not found at the site of MC-collagen fibrils contact, whereas the secretome and fibrils were directly contacted. We observed direct and mediator-based interactions between MCs and paraganglioma cells. The latter preserved their membrane integrity when MC granules were not in proximity. The effects of the MC secretome on the paraganglioma microenvironment demonstrated its pathogenetic role in tumor progression and allow its application to new diagnostic criteria and the development of protocols for personalized therapy. RESEARCH HIGHLIGHTS: Ultrastructural analysis reveals novel regulatory effects of mast cells via diverse secretory pathways on the pathogenesis of parasympathetic paraganglioma, including fibrous extracellular matrix remodeling and mediator-based interactions between MCs and cells of the tumor microenvironment.

Histoarchitecture of stromal collagen fibers in gastrointestinal hollow organs of mice after a 30-day space flight.

The digestive organs are highly sensitive to the influence of orbital flight factors and can limit the professional activities of crew members aboard the International Space Station. Connective tissue, as a system-forming matrix of the integrative-buffer metabolic environment, is of particular relevance in space biomedicine, ensuring the functioning of internal organs under an altered gravitational stimulus. However, the adaptive mechanisms of the fibrous extracellular matrix of the gastric and intestinal connective tissue have not been fully investigated under prolonged microgravity weightlessness. Using histochemical techniques, we experimentally studied the state of collagen fibers in the specific tissue microenvironment of the gastric and intestinal membranes in C57BL/6 N mice after a 30-day space flight, subsequent 7-day ground readaptation, and in animals of the relevant control groups. The 30-day stay of laboratory animals aboard the Bion-M 1 biosatellite resulted in a reduction in the fibrous extracellular matrix of connective tissue in the studied digestive organs, excepting the gastric lamina propria. Increased fibrillogenesis was revealed in the gastrointestinal mucous membranes of animals 7 days after biosatellite landing compared with the parameters of animals in the space flight group. During the experiment with ground simulated orbital flight conditions, changes in collagen fibers were not significant compared to the vivarium control group. Thus, the results obtained evidence gravisensitivity of the fibrous extracellular matrix of the intraorgan connective tissue. This fact also highlights the necessity to further improve gastrointestinal tract-related preventive measures for astronauts during orbital flight.

Initial characterization of a transgenic mouse with overexpression of the human D1-dopamine receptor in the heart.

Dopamine can exert effects in the mammalian heart via five different dopamine receptors. There is controversy whether dopamine receptors increase contractility in the human heart. Therefore, we have generated mice that overexpress the human D1-dopamine receptor in the heart (D1-TG) and hypothesized that dopamine increases force of contraction and beating rate compared to wild-type mice (WT). In D1-TG hearts, we ascertained the presence of D1-dopamine receptors by autoradiography using [3H]SKF 38393. The mRNA for human D1-dopamine receptors was present in D1-TG hearts and absent in WT. We detected by in-situ-hybridization mRNA for D1-dopamine receptors in atrial and ventricular D1-TG cardiomyocytes compared to WT but also in human atrial preparations. We noted that in the presence of 10 µM propranolol (to antagonize ß-adrenoceptors), dopamine alone and the D1- and D5-dopamine receptor agonist SKF 38393 (0.1-10 µM cumulatively applied) exerted concentration- and time-dependent positive inotropic effects and positive chronotropic effects in left or right atrial preparations from D1-TG. The positive inotropic effects of SKF 38393 in left atrial preparations from D1-TG led to an increased rate of relaxation and accompanied by and probably caused by an augmented phosphorylation state of the inhibitory subunit of troponin. In the presence of 0.4 µM propranolol, 1 µM dopamine could increase left ventricular force of contraction in isolated perfused hearts from D1-TG. In this model, we have demonstrated a positive inotropic and chronotropic effect of dopamine. Thus, in principle, the human D1-dopamine receptor can couple to contractility in the mammalian heart.

Assessment of the Severity and the Remission Criteria in Eosinophilic Esophagitis.

Eosinophilic esophagitis (EoE) is an immune-mediated disease that manifests with dysphagia and is characterized by the predominantly eosinophilic infiltration of the esophageal mucosa. Several instruments have been developed to assess the symptoms of EoE: the Daily Symptom Questionnaire (DSQ), EoE Activity Index (EEsAI), Pediatric EoE Symptom Severity (PEESSv2), etc. The use of the EREFS is a gold standard for endoscopic diagnosis. The EoE histologic scoring system (EoEHSS) was elaborated for the assessment of histological features in EoE. However, the remission criteria are not clearly defined and vary greatly in different studies. Gastroenterologists establish the severity of EoE mainly based on endoscopic findings. At the same time, EoE requires a multidisciplinary approach. The recently developed Index of Severity of Eosinophilic Esophagitis (I-SEE) that is built on symptoms, endoscopic findings, and histological features is promising.

Smooth Muscle Actin as a Criterion for Gravisensitivity of Stomach and Jejunum in Laboratory Rodents.

Smooth muscle tissue (SMT) is one of the main structural components of visceral organs, acting as a key factor in the development of adaptive and pathological conditions. Despite the crucial part of SMT in the gastrointestinal tract activity, the mechanisms of its gravisensitivity are still insufficiently studied. The study evaluated the content of smooth muscle actin (α-SMA) in the membranes of the gastric fundus and jejunum in C57BL/6N mice (30-day space flight), in Mongolian gerbils Meriones unguiculatus (12-day orbital flight) and after anti-orthostatic suspension according to E.R. Morey-Holton. A morphometric analysis of α-SMA in the muscularis externa of the stomach and jejunum of mice and Mongolian gerbils from space flight groups revealed a decreased area of the immunopositive regions, a fact indicating a weakening of the SMT functional activity. Gravisensitivity of the contractile structures of the digestive system may be due to changes in the myofilament structural components of the smooth myocytes or myofibroblast actin. A simulated antiorthostatic suspension revealed no significant changes in the content of the α-SMA expression level, a fact supporting an alteration in the functional properties of the muscularis externa of the digestive hollow organs under weightless environment. The data obtained contribute to the novel mechanisms of the SMT contractile apparatus remodeling during orbital flights and can be used to improve preventive measures in space biomedicine.

Space-Flight- and Microgravity-Dependent Alteration of Mast Cell Population and Protease Expression in Digestive Organs of Mongolian Gerbils.

Mast cell (MC)-specific proteases are of particular interest for space biology and medicine due to their biological activity in regulating targets of a specific tissue microenvironment. MC tryptase and chymase obtain the ability to remodel connective tissue through direct and indirect mechanisms. Yet, MC-specific protease expression under space flight conditions has not been adequately investigated. Using immunohistochemical stainings, we analyzed in this study the protease profile of the jejunal, gastric, and hepatic MC populations in three groups of Mongolian gerbils-vivarium control, synchronous experiment, and 12-day orbital flight on the Foton-M3 spacecraft-and in two groups-vivarium control and anti-orthostatic suspension-included in the experiment simulating effects of weightlessness in the ground-based conditions. After a space flight, there was a decreased number of MCs in the studied organs combined with an increased proportion of chymase-positive MCs and MCs with a simultaneous content of tryptase and chymase; the secretion of specific proteases into the extracellular matrix increased. These changes in the expression of proteases were observed both in the mucosal and connective tissue MC subpopulations of the stomach and jejunum. Notably, the relative content of tryptase-positive MCs in the studied organs of the digestive system decreased. Space flight conditions simulated in the synchronous experiment caused no similar significant changes in the protease profile of MC populations. The space flight conditions resulted in an increased chymase expression combined with a decreased total number of protease-positive MCs, apparently due to participating in the processes of extracellular matrix remodeling and regulating the state of the cardiovascular system.

Cellular and Molecular Mechanisms of the Tumor Stroma in Colorectal Cancer: Insights into Disease Progression and Therapeutic Targets.

Colorectal cancer (CRC) is a major health burden worldwide and is the third most common type of cancer. The early detection and diagnosis of CRC is critical to improve patient outcomes. This review explores the intricate interplay between the tumor microenvironment, stromal interactions, and the progression and metastasis of colorectal cancer. The review begins by assessing the gut microbiome's influence on CRC development, emphasizing its association with gut-associated lymphoid tissue (GALT). The role of the Wnt signaling pathway in CRC tumor stroma is scrutinized, elucidating its impact on disease progression. Tumor budding, its effect on tumor stroma, and the implications for patient prognosis are investigated. The review also identifies conserved oncogenic signatures (COS) within CRC stroma and explores their potential as therapeutic targets. Lastly, the seed and soil hypothesis is employed to contextualize metastasis, accentuating the significance of both tumor cells and the surrounding stroma in metastatic propensity. This review highlights the intricate interdependence between CRC cells and their microenvironment, providing valuable insights into prospective therapeutic approaches targeting tumor-stroma interactions.

Mast Cells as a Potential Target of Molecular Hydrogen in Regulating the Local Tissue Microenvironment.

Knowledge of the biological effects of molecular hydrogen (H2), hydrogen gas, is constantly advancing, giving a reason for the optimism in several healthcare practitioners regarding the management of multiple diseases, including socially significant ones (malignant neoplasms, diabetes mellitus, viral hepatitis, mental and behavioral disorders). However, mechanisms underlying the biological effects of H2 are still being actively debated. In this review, we focus on mast cells as a potential target for H2 at the specific tissue microenvironment level. H2 regulates the processing of pro-inflammatory components of the mast cell secretome and their entry into the extracellular matrix; this can significantly affect the capacity of the integrated-buffer metabolism and the structure of the immune landscape of the local tissue microenvironment. The analysis performed highlights several potential mechanisms for developing the biological effects of H2 and offers great opportunities for translating the obtained findings into clinical practice.

Signaling Pathways in the Pathogenesis of Barrett's Esophagus and Esophageal Adenocarcinoma.

Barrett's esophagus (BE) is a premalignant lesion that can develop into esophageal adenocarcinoma (EAC). The development of Barrett's esophagus is caused by biliary reflux, which causes extensive mutagenesis in the stem cells of the epithelium in the distal esophagus and gastro-esophageal junction. Other possible cellular origins of BE include the stem cells of the mucosal esophageal glands and their ducts, the stem cells of the stomach, residual embryonic cells and circulating bone marrow stem cells. The classical concept of healing a caustic lesion has been replaced by the concept of a cytokine storm, which forms an inflammatory microenvironment eliciting a phenotypic shift toward intestinal metaplasia of the distal esophagus. This review describes the roles of the NOTCH, hedgehog, NF-κB and IL6/STAT3 molecular pathways in the pathogenesis of BE and EAC.

Mast Cell Tryptase and Carboxypeptidase A3 in the Formation of Ovarian Endometrioid Cysts.

The mechanisms of ovarian endometrioid cyst formation, or cystic ovarian endometriosis, still remain to be elucidated. To address this issue, we analyzed the involvement of mast cell (MC) tryptase and carboxypeptidase A3 (CPA3) in the development of endometriomas. It was found that the formation of endometrioid cysts was accompanied by an increased MC population in the ovarian medulla, as well as by an MC appearance in the cortical substance. The formation of MC subpopulations was associated with endometrioma wall structures. An active, targeted secretion of tryptase and CPA3 to the epithelium of endometrioid cysts, immunocompetent cells, and the cells of the cytogenic ovarian stroma was detected. The identification of specific proteases in the cell nuclei of the ovarian local tissue microenvironment suggests new mechanisms for the regulatory effects of MCs. The cytoplasmic outgrowths of MCs propagate in the structures of the stroma over a considerable distance; they offer new potentials for MC effects on the structures of the ovarian-specific tissue microenvironment under pathological conditions. Our findings indicate the potential roles of MC tryptase and CPA3 in the development of ovarian endometriomas and infer new perspectives on their uses as pharmacological targets in personalized medicine.

Mast Cells in Regeneration of the Skin in Burn Wound with Special Emphasis on Molecular Hydrogen Effect.

The mechanisms of regeneration for the fibrous component of the connective tissue of the dermis are still insufficiently studied. The aim of this study was to evaluate the effectiveness of the use of molecular hydrogen on the local therapy of a II degree burn wound with the intensification of collagen fibrillogenesis in the skin. We analyzed the involvement of mast cells (MCs) in the regeneration of the collagen fibers of the connective tissue using water with a high content of molecular hydrogen and in a therapeutic ointment for the cell wounds. Thermal burns led to an increase in the skin MC population, accompanied by a systemic rearrangement of the extracellular matrix. The use of molecular hydrogen for the treatment of burn wounds stimulated the regeneration processes by activating the formation of the fibrous component of the dermis, accelerating wound healing. Thus, the intensification of collagen fibrillogenesis was comparable to the effects of a therapeutic ointment. The remodeling of the extracellular matrix correlated with a decrease in the area of damaged skin. Skin regeneration induced by the activation of the secretory activity of MCs may be one of the possible points of implementation of the biological effects of molecular hydrogen in the treatment of burn wounds. Thus, the positive effects of molecular hydrogen on skin repair can be used in clinical practice to increase the effectiveness of therapy after thermal exposure.

The Remodeling of Dermal Collagen Fibrous Structures in Mice under Zero Gravity: The Role of Mast Cells.

Mechanisms of adaptive rearrangements of the fibrous extracellular matrix of connective tissues under microgravity practically remain unexplored, despite the most essential functions of the stroma existing to ensure the physiological activity of internal organs. Here we analyzed the biomaterial (the skin dermis) of C57BL/6J mice from the Rodent Research-4 experiment after a long stay in space flight. The biomaterial was fixed onboard the International Space Station. It was found that weightlessness resulted in a relative increase in type III collagen-rich fibers compared to other fibrous collagens in the skin. The number of mast cells in the skin did not change, but their secretory activity increased. At the same time, co-localization of mast cells with fibroblasts, as well as impregnated fibers, was reduced. Potential molecular-cellular causes of changes in the activity of fibrillogenesis under zero-gravity conditions and the slowdown of the polymerization of tropocollagen molecules into supramolecular fibrous structures, as well as a relative decrease in the number of fibrous structures with a predominant content of type-I collagen, are discussed. The data obtained evidence of the different sensitivity levels of the fibrous and cellular components of a specific tissue microenvironment of the skin to zero-gravity conditions. The obtained data should be taken into account in the systematic planning of long-term space missions in order to improve the prevention of undesirable effects of weightlessness.

Chloroacetate esterase reaction combined with immunohistochemical characterization of the specific tissue microenvironment of mast cells.

This study provides a combined histochemical method for detecting enzyme activity of chloroacetate esterase simultaneously with immunolabeling of the components of a specific tissue microenvironment on formalin-fixed, paraffin-embedded specimens. Chromogenic detection of the molecular targets within and outside the mast cells provides novel options in determining the histoarchitectonics of organ-specific mast cell populations, studying the functional significance of chloroacetate esterase and specifying the immune landscape of the tissue microenvironment.

Protease Profile of Tumor-Associated Mast Cells in Melanoma.

Mast cells (MCs) produce a variety of mediators, including proteases-tryptase, chymase, and carboxypeptidases-which are important for the immune response. However, a detailed assessment of the mechanisms of biogenesis and excretion of proteases in melanoma has yet to be carried out. In this study, we present data on phenotype and secretory pathways of proteases in MCs in the course of melanoma. The development of melanoma was found to be accompanied by the appearance in the tumor-associated MC population of several pools with a predominant content of one or two specific proteases with a low content or complete absence of others. Elucidation of the molecular and morphological features of the expression of MC proteases in melanoma allows us a fresh perspective of the pathogenesis of the disease, and can be used to clarify MCs classification, the disease prognosis, and evaluate the effectiveness of ongoing antitumor therapy.