Pax6 Expression Research Articles

Mycophenolate mofetil reduces cell viability associated with the miR-205-PAX9 pathway in human lip fibroblast cells

Cleft lip is a birth defect associated with environmental and genetic factors. Recently, microRNAs (miRNAs) have been reported to play a crucial role in lip formation, with the disruption of miRNAs influencing the development of cleft lip. Exposure to medicinal agents in pregnant women is one of the reasons for cleft lip. Although an association between pharmaceuticals-induced cleft lip and miRNAs has been suggested, it remains to be fully elucidated. This study aimed to clarify the molecular mechanism of mycophenolate mofetil (MPM)-induced inhibition of cell proliferation and miRNA expression in human lip fibroblast (KD) cells. Cell viability, apoptosis, and cell cycle-related markers were evaluated after 72 h of MPM treatment. In addition, miRNA levels and the expression of their downstream genes were measured, and a rescue experiment was performed by overexpressing PAX9. We showed that MPM dose-dependently reduced the viability of KD cells. In addition, MPM treatment suppressed cyclin-D1 and cyclin dependent kinase-6 expression in KD cells. Furthermore, MPM upregulated miR-205 expression and downregulated the expression of PAX9 (downstream gene). Moreover, PAX9 overexpression alleviated MPM-induced inhibition of cell proliferation. These results suggest that MPM suppresses cell viability by modulating miR-205-PAX9 expression.

DNA methylation patterns are influenced by Pax3::Foxo1 expression and developmental lineage in rhabdomyosarcoma tumours forming in genetically engineered mouse models.

Rhabdomyosarcoma (RMS) is a family of phenotypically myogenic paediatric cancers consisting of two major subtypes: fusion-positive (FP) RMS, most commonly involving the PAX3::FOXO1 fusion gene, formed by the fusion of paired box 3 (PAX3) and forkhead box O1 (FOXO1) genes, and fusion-negative (FN) RMS, lacking these gene fusions. In humans, DNA methylation patterns distinguish these two subtypes as well as mutation-associated subsets within these subtypes. To investigate the biological factors responsible for these methylation differences, we profiled DNA methylation in RMS tumours derived from genetically engineered mouse models (GEMMs) in which various driver mutations were introduced into different myogenic lineages. Our unsupervised analyses of DNA methylation patterns in these GEMM tumours yielded two major clusters, corresponding to high and no/low expression of Pax3::Foxo1, which mirrored the results for human FP and FN RMS tumours. Two distinct methylation-defined subsets were found for GEMM RMS tumours with no/low Pax3::Foxo1 expression: one subset enriched in Pax7 lineage tumours and a second subset enriched in myogenic factor 5 (Myf5) lineage tumours. Integrative analysis of DNA methylation and transcriptomic data in mouse and human RMS revealed a common group of differentially methylated and differentially expressed genes, highlighting a conserved set of genes functioning in both human RMS models and GEMMs of RMS. In conclusion, these studies provide insight into the roles of oncogenic fusion proteins and developmental lineages in establishing DNA methylation patterns in FP and FN RMS respectively. © 2025 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Immunohistochemical Expression of PAX8 in Central Nervous System Hemangioblastomas: A Potential Diagnostic Pitfall for Neuropathologists.

The histologic differential diagnosis between intracranial hemangioblastoma (HB) and metastatic clear cell renal cell carcinoma may be challenging, especially considering that both tumors exhibit clear cell morphology and can be associated with vHL mutation and/or Von Hippel-Lindau syndrome. As the execution of immunohistochemical analyses is often mandatory, the expression of PAX8 has been traditionally considered a reliable marker of metastatic clear cell renal cell carcinoma, being consistently negative in intracranial HB. However, as in recent years, some cases of PAX8-positive HBs have been reported in the literature; we studied the expression of this antibody on a series of 23 intracranial HB, showing that about 40% of these tumors may express PAX8 and that this immunoreactivity is often focal and weak. We would like to emphasize that the possibility of a PAX8-positive intracranial HB does exist and must be taken into account by neuropathologists to avoid misdiagnoses; in this regard, a broader immunohistochemical panel also including CD10, Inhibin-α, PAX2, S100, and anti-Renal cell carcinoma (RCC) antibody is highly recommended.

Expression of PAX6 and Keratocyte-Characteristic Markers in Human Limbal Stromal Cells of Congenital Aniridia and Healthy Subjects, In Vitro

Purpose Our aim was to examine the expression of PAX6 and keratocyte-specific markers in human limbal stromal cells (LSCs) in congenital aniridia (AN) and in healthy corneas, in vitro. Methods Primary human LSCs were extracted from individuals with aniridia (AN-LSCs) (n = 8) and from healthy corneas (LSCs) (n = 8). The cells were cultured in either normal-glucose serum-containing cell culture medium (NGSC-medium) or low-glucose serum-free cell culture medium (LGSF-medium). Analysis of PAX6 and keratocyte-specific markers was conducted using qPCR and Western blotting. The keratocyte-specific markers included Collagen I (COL1A1), Collagen III (COL3A1), Collagen V (COL5A1), α-smooth muscle actin (ACTA2), Aldehyde Dehydrogenase 3 Family, Member A1 (ALDH3A1), Keratocan (KER), Lumican (LUM), and CD34. Results PAX6 mRNA expression exhibited a significant decrease in AN-LSCs compared to LSCs in both NGSC- and LGSF-medium (p = 0.04; p = 0.014). There was a marked reduction in COL5A1 mRNA expression (p = 0.011), accompanied by notably higher ALDH3A1 and KER mRNA levels (p = 0.007; p = 0.013) in AN-LSCs compared to LSCs when using NGSC-medium. In LGSF-medium, AN-LSCs showed a significant increase in COL1A1 and COL5A1 mRNA expression compared to LSCs (p = 0.048; p = 0.002). Moreover, COL1A1 and α-SMA protein expression were significantly elevated in AN-LSCs compared to LSCs in LGSF-medium (p = 0.048, p = 0.008). Conclusions Our investigation affirms the altered expression of PAX6 and keratocyte-specific markers in AN-LSCs relative to healthy controls. Both NGSC- and LGSF-medium exerted distinct effects on both LSCs and AN-LSCs. The observed variations in PAX6 and keratocyte-specific marker expression in AN-LSCs may play a pivotal role in the development and progression of aniridia-associated keratopathy.

Hypertensive disorders of pregnancy affected thyroid hormone synthesis via endoplasmic reticulum stress in preterm infant rats.

Maternal hypertensive disorders of pregnancy (HDP) was associated with increased risk of congenital hypothyroidism in preterm infants, but its underlying mechanisms remain unclear. To investigate the possible mechanisms by which intrauterine exposure to HDP affects thyroid hormone synthesis in preterm infant rats. preterm infant rats were obtained by Caesarean section delivery from the L-NAME group and Control groups which was induced by L-NAME and saline, respectively. Thyroid hormone levels of preterm infant rats were detected by ELISA, and morphology structure were observed by H&E staining and electron microscopy, and the expression of key factors of thyroid hormone synthesis and endoplasmic reticulum stress indicators were analyzed by RT-qPCR and Western blotting. Compared with the Control group, significantly higher serum TSH concentration was observed in the L-NAME group (p<0.05), while T3 and T4 levels showed no noticeable change. The L-NAME group revealed a reduction in the size and number of thyroid follicles, with the emergence of thyroid follicular epithelial hyperplasia. While electron microscopy revealed that the endoplasmic reticulum of thyroid follicular epithelial cells was marked swollen within L-NAME group. Additionally, the mRNA expression of Ttf1, Pax8 and Tshr was down-regulated in thyroid tissues of L-NAME group. Furthermore, the protein levels of Tg, NIS and TSHR were reduced, while the protein level of p-IRE1α, ATF6α, XBP1s and Bip were increased in the L-NAME group. The results indicated that HDP may reduce the expression of key molecules involved in thyroid synthesis through endoplasmic reticulum stress which could ultimately result in the development of congenital hypothyroidism.

Molecular mechanism of METTL14-mediated m6A modification regulating microglial function post ischemic stroke

This study explores the molecular mechanism of METTL14 regulating microglial function post ischemic stroke. A murine model was established by tMCAO. The neurological function was evaluated by mNSS. The cerebral infarct size and pathological changes were observed by TTC and H&E staining. M1 and M2 microglia in brain tissues were detected by flow cytometry. BV2 cells were subjected to OGD/R to establish an in vitro model. qRT-PCR and Western blot were used for detecting METTL14, PAX6, YTHDF2, TREM2, iNOS, and Arg1 expressions. The m6A level was quantitatively analyzed, and the binding of YTHDF2 or m6A to PAX6 was analyzed by RIP. PAX6 mRNA stability was assessed after actinomycin D treatment. ChIP was utilized for determining the enrichment of PAX6 on TREM2 promoter. The binding relationship between TREM2 and PAX6 was verified by dual-luciferase reporter assay. METTL14 was highly expressed after tMCAO, and silence of METTL14 alleviated symptoms of tmcao mice and promoted microglial M2 polarization. METTL14 enhanced PAX6 mRNA m6A modification to promote YTHDF2 binding to PAX6 mRNA and its degradation. PAX6 bound to TREM2 promoter and facilitated its transcription and expression. In conclusion, METTL14-mediated m6A modification aggravates ischemic stroke by promoting microglial M1 polarization via YTHDF2/PAX6/TREM2 axis.

The CB1 antagonist Rimonabant improves muscle regeneration and remodels the inflammatory and endocannabinoid profile upon injury in male mice.

Skeletal muscle regeneration upon injury requires timely activation of inflammatory, myogenic, fibrotic, apoptotic and anabolic systems. Optimization of these features might improve the recovery process. Whereas recent data indicate that the endocannabinoid system, and more particularly cannabinoid receptor 1 (CB1) antagonism, is involved in the regulation of inflammatory, myogenic, fibrotic, apoptotic and anabolic pathways, it was never studied whether CB1 antagonism can improve muscle regeneration. The present study investigated the effect of the CB1 antagonist Rimonabant (10 mg/kg/d) on functional (5 days post-cardiotoxin injury; 5DPI) and molecular muscle responses (3DPI and 7DPI) in mice. Rimonabant prevented cardiotoxin-induced muscle strength loss 5DPI, increased myofiber growth (7DPI) and improved the muscle molecular profile 3DPI and 7DPI. In general, inflammation (e.g. p-p65NF-κB, CD80) and apoptosis (e.g. cleaved caspase-3, cleaved PARP) were downregulated by Rimonabant, whereas it upregulated the expression of Pax7 but other myogenic factors remained unaffected by rimonabant. In addition, Rimonabant restored the injury-induced (inflammatory) lipid profile to a large extent, including oxygenated fatty acids, unsaturated fatty acids and endocannabinoids such as 2-arachidonoyl glycerol and palmitoylethanolamide. Altogether, these data show that the endocannabinoid system might be a novel therapeutic target to improve muscle regeneration, which is relevant for age- and disease-related muscle degeneration.

Impact of photobiomodulation on neural embryoid body formation from immortalized adipose-derived stem cells

BackgroundEmbryoid bodies (EBs) are three-dimensional (3D) multicellular cell aggregates that are derived from stem cell and play a pivotal role in regenerative medicine. They recapitulate many crucial aspects of the early stages of embryonic development and is the first step in the generation of various types of stem cells, including neuronal stem cells. Current methodologies for differentiating stem cells into neural embryoid bodies (NEBs) in vitro have advanced significantly, but they still have limitations which necessitate improvement. Photobiomodulation (PBM) a low powered light therapy is a non-invasive technique shown to promote stem cell proliferation and differentiation.MethodsThis in vitro study elucidated the effects of photobiomodulation (PBM) on the differentiation of immortalized adipose-derived stem cells (iADSCs) into NEBs within a 3D cell culture environment. The study utilized PBM at wavelengths of 825 nm, 525 nm, and a combination of both, with fluences of 5 and 10 J/cm2. Morphology, viability, metabolic activity, and differentiation following PBM treatment was analysed.ResultsThe results revealed that the effects of photobiomodulation (PBM) are dose dependent. PBM, at 825 nm with a fluence of 10 J/cm2, significantly enhanced the size of neural embryoid bodies (NEBs), improved cell viability and proliferation, and reduced lactate dehydrogenase (LDH) levels, indicating minimal cell damage. Interestingly, the stem cell marker CD 44 was upregulated at 5 J/cm2 in all treatment groups at 24 and 96 hpi, CD105 increased with 825 nm at 10 J/cm2 at 24 hpi, which may be attributed to a heterogeneous cell population within the NEBs. Pax6 expression showed transient activation. Nestin was upregulated at 825 nm with 10 J/cm2 at 96 hpi, suggesting a promotion of neural precursor populations. GFAP an intermediate filament protein was upregulated at 825 nm at 10 J/cm2 at both 24 and 96 hpi. SOX2, a pluripotency marker, was expressed at 5 J/cm2 across all wavelengths. Neu N a neuronal nuclei marker was expressed at 5 J/cm2 in all treatments at 24 hpi and over time the expression was observed in all treatment groups at 10 J/cm2.ConclusionIn conclusion, the application of PBM at 825 nm with a fluence of 10 J/cm2 during the differentiation of iADSCs into NEBs resulted in optimal differentiation. Notably, the neuronal marker Nestin was significantly upregulated, highlighting the potential of the PBM approach for enhancing neuronal differentiation its promising applications in regenerative medicine.Graphical

Regulation of corneal epithelial differentiation: miR-141-3p promotes the arrest of cell proliferation and enhances the expression of terminal phenotype.

In recent years, different laboratories have provided evidence on the role of miRNAs in regulation of corneal epithelial metabolism, permeability and wound healing, as well as their alteration after surgery and in some ocular pathologies. We searched the available databases reporting miRNA expression in the human eye, looking for miRNAs highly expressed in central cornea, which could be crucial for maintenance of the epithelial phenotype. Using the rabbit RCE1(5T5) cell line as a model of corneal epithelial differentiation, we describe the participation of miR-141-3p as a possible negative regulator of the proliferative/migratory phenotype in corneal epithelial cells. The expression of miR-141-3p followed a time course similar to the differentiation-linked KRT3 cytokeratin, being delayed 24-48 hours relative to PAX6 expression; such result suggested that miR-141-3p only regulates the expression of terminal phenotype. Inhibition of miR-141-3p led to increased cell proliferation and motility, and induced the expression of molecular makers characteristic of an Epithelial Mesenchymal Transition (EMT). Comparison between the transcriptional profile of cells in which miR-141-3p was knocked down, and the transcriptomes from proliferative non-differentiated and differentiated stratified epithelia suggest that miR-141-3p is involved in the expression of terminal differentiation mediating the arrest of cell proliferation and inhibiting the EMT in highly motile early differentiating cells.

Comparative Analysis of Different Extracellular Matrices for the Maintenance of Bovine Satellite Cells.

Cultured meat produced using satellite cells has emerged to address issues such as overpopulation, the ethical conundrums associated with the breeding environment, and the methane gas emissions associated with factory farming. To date, however, the challenges of maintaining satellite cells in vitro and reducing the costs of the culture media are still substantial. Gelatin, collagen, and fibronectin are commonly used extracellular matrices (ECMs) that facilitate signal integration with the cells and promote cell adhesion. In this study, we compared the proliferation, cell cycle, immunocytochemistry, and expression levels of Pax7, Pax3, Myf5, MyoD1, and MyoG genes in bovine satellite cells (BSCs) cultured on gelatin-, collagen- and fibronectin-coated dishes as part of short- and long-term cultures. We observed that BSCs cultured on gelatin-coated dishes showed higher levels of Pax7 expression than BSCs cultured on collagen- and fibronectin-coated dishes in both short- and long-term cultures, indicating that BSCs cultured on gelatin effectively maintained the satellite cell population in both the short- and long-term cultures. Our study highlights that gelatin is an effective ECM for the maintenance of BSCs and the production of cultured meat.

Characterization of gastric/gastrointestinal-like immunophenotypes in endometrial endometrioid adenocarcinomas, including endometrioid adenocarcinomas with mucinous differentiation.

Endometrial mucinous carcinoma of the gastric [gastrointestinal] type (MCG) is a rare, possibly aggressive subtype of endometrial cancer that should be distinguished from its potential mimics, including endometrioid carcinoma (EEC). Herein, we assess the frequency of gastric and gastrointestinal immunophenotypes in EEC without any discernible gastric/gastrointestinal-type morphology. Immunohistochemical analyses for KRT(CK)7, KRT20, CDX2, ER, SATB2, MUC6, PAX8, and HIK1083 were performed on 81 EEC, inclusive of consecutively archived low grade [with (n=22) and without (n=47) mucinous differentiation] and high grade (n=12) cases. None displayed gastric-type morphology or goblet cells. Expression levels were semi-quantified as H-scores (combining intensity and extent of staining) on a standardized 0-300 scale. Among the gastric/gastrointestinal-type markers, 56%, 62%, 23%, 25%, and 0% of cases expressed MUC6, CDX2, KRT20, SATB2, and HIK1083 respectively. The expression levels for positive cases were generally limited, with average H-scores being 49.5 [range 1-250] for MUC6, 33.7 [1-285] for CDX2, 24.0 [1-270] for CK20, and 30.5 [2-220] for SATB2. Ten (12.35%) cases showed high expression (H≥200) of at least 1 gastric/gastrointestinal-type marker, including 1, 2, 2 and 6 cases that were high positive for KRT20, SATB2, CDX2 and MUC6 respectively. Immunoreactive foci were generally indistinguishable from background at the morphologic level. There was no statistically significant correlation between the expression of any of the gastric/gastrointestinal-type markers and ER, KRT7 or PAX8 expression. In summary, gastric/gastrointestinal-type proteins are not uncommonly expressed at low levels in EEC. As such, positivity for these markers cannot be the sole basis for distinguishing EEC from MCG.

The glycosyltransferase POGLUT1 regulates muscle stem cell development and maintenance in mice.

Mutations in protein O -glucosyltransferase 1 ( POGLUT1 ) cause a recessive form of limb-girdle muscular dystrophy (LGMD-R21) associated with reduced satellite cell number and NOTCH1 signaling in adult patient muscles and impaired myogenic capacity of patient-derived muscle progenitors. However, the in vivo roles of POGLUT1 in the development, function, and maintenance of satellite cells are not well understood. Here, we show that conditional deletion of mouse Poglut1 in myogenic progenitors leads to early lethality, postnatal muscle growth defects, reduced Pax7 expression, abnormality in muscle extracellular matrix, and impaired muscle repair. Poglut1 -deficient muscle progenitors exhibit reduced proliferation, enhanced differentiation, and accelerated fusion into myofibers. Inducible loss of Poglut1 in adult satellite cells leads to their precocious differentiation and impairs muscle repair upon serial injury. Cell-based signaling assays and mass spectrometric analysis indicate that POGLUT1 is required for the activation of NOTCH1, NOTCH2, and NOTCH3 in myoblasts and that NOTCH3 is a target of POGLUT1 like NOTCH1 and NOTCH2. These observations provide insight into the roles of POGLUT1 in muscle development and repair and the pathophysiology of LGMD-R21.

Treatment with tofacitinib attenuates muscle loss through myogenin activation in the collagen-induced arthritis

BackgroundSarcopenia is a muscle disease characterized by reduction of muscle strength and muscle mass. In RA, 25.9 to 43.3% of the patients present sarcopenia. The loss of muscle mass observed in RA patients occurs either by activation of catabolic pathways or by inhibition of anabolic pathways. Despite having a list of drugs capable of treating RA inflammation, their effect on muscle is unclear. Our objective was to evaluate the tofacitinib effect on the muscle mass of collagen-induced arthritis (CIA) mice.MethodsCIA was induced in male DBA/1J mice by subcutaneous injection of Type 2 Collagen plus Freund Adjuvant. Animals were randomized into 3 groups: CIA + tofacitinib; CIA + vehicle; and healthy controls. Treatment was administered twice a day, between days 18 and 45 after induction. Clinical score, edema, and body weight were evaluated during the experimental period. After euthanasia, tibiotarsal joints were collected for assessment of disease histopathological score, and tibialis anterior (TA) and gastrocnemius (GA) muscles were weighed to assess muscle mass. Muscle atrophy was evaluated by measurement of TA myofiber cross-sectional area (CSA). Protein expression was evaluated by western blot using GA homogenates. Serum inflammatory markers were evaluated by ELISA. Statistical analysis included ANOVA followed by Tukey’s or with Kruskal-Wallis. The statistical difference was assumed for p < 0.05.ResultsTofacitinib treatment decreased arthritis severity by reducing clinical score, and hind paw edema in comparison with the vehicle group. Tofacitinib showed weight gain, higher TA and GA weights, and increased CSA compared to the vehicle group. On day 45, Tofacitinib presented increased muscle strength compared to the vehicle group, however, no difference was found in muscle fatigue. Pax7 expression was unchanged, while MyoD expression showed an increasing trend, and myogenin expression was significantly increased in Tofacitinib compared to vehicle and control groups. The treatment didn’t modify Murf-1 expression. Tofacitinib mice showed decreased serum levels of TNF and increased IL-6 serum levels.ConclusionTofacitinib attenuated muscle loss in arthritic mice, increased muscle weight and muscle CSA. Activation of satellite cell regeneration, based on the increased expression of myogenin, is a potential mechanism involved in tofacitinib action against muscle loss.

Platelet-rich plasma ameliorates dexamethasone-induced myopathy by suppressing autophagy and enhancing myogenic potential through modulation of Myo-D, Pax-7, and myogenin expression

BackgroundMuscle tissue is essential for overall well-being that declines with age and different illnesses. Glucocorticoids, despite being efficient in treating inflammation, can induce muscle weakness (known as glucocorticoid-induced myopathy) by affecting protein breakdown and synthesis. Glucocorticoids have a negative impact on satellite cells, which play a role in muscle regeneration. Platelet rich plasma (PRP), containing concentrated growth factors, has a potential role in enhancing tissue repair and could be used to ameliorates combat muscle wasting caused by glucocorticoids. AimThe purpose of this study was to identify how PRP can affect dexamethasone-induced myopathy in a rat model. MethodsTwenty-four male rats were divided into four equal groups: control, PRP, steroid (dexamethasone) treated for induction of myopathy, and steroid then treated with PRP for three weeks. Skeletal muscle contractile properties, protein content of the muscle, oxidative stress markers, histological structure, myogenin gene expression and immunohistochemical expression of Myo-D, Pax-7 and LC3 were assessed. Resultsdexamethasone caused significant muscle weakness, decreased protein content, increased oxidative stress, decreased expression of myogenic genes and upregulated LC3 expression. PRP administration significantly improved muscle function, increased protein content, reduced oxidative stress, and upregulated myogenic genes. Histological results confirmed these findings. Additionally, PRP decreased autophagy marker LC3 expression and increased muscle stem cell markers MyoD and Pax7. ConclusionThese results suggested that PRP could effectively prevent and reverse dexamethasone-induced muscle atrophy by promoting muscle protein synthesis, reducing oxidative stress, decreasing autophagy, and enhancing muscle stem cell activity. This study supports the potential role of PRP as a therapeutic strategy for muscle wasting disorders.

Effects of miR-204-5p modulation on PAX6 regulation and corneal inflammation

Congenital aniridia is a rare eye disease characterized by loss of PAX6 protein leading to aniridia-associated keratopathy that significantly reduces vision. The miR-204-5p is a possible regulator of PAX6 function and here we evaluate its effect in multiple in vitro and in vivo models. In vitro, miR-204-5p overexpression suppressed vascular factor ANGPT1 in human limbal stem cells (T-LSC) and Pax6-knockdown LSC (mut-LSC), and in primary human limbal epithelial cells (LEC) at the gene and protein levels and following LPS stimulation. However, miR-204-5p inhibited VEGFA expression only in mut-LSCs and LPS-stimulated LEC. Also, miR-204-5p increased PAX6 expression in mut-LSC and differentiated corneal epithelial cells, but not in LEC. Topical miR-204-5p after LPS-induced keratitis in mice failed to suppress Vegfa, Angpt1, Il-1β, and Tnf-α or rescue Pax6 levels in contrast to in vitro results, although it significantly reduced the inflammatory infiltrate in the cornea. In Pax6Sey/+ aniridia mice, miR-204-5p did not rescue PAX6 levels or suppress Vegfa, Angpt1, or inhibit the ERK1/2 pathway. While short-term miR-204-5p treatment effectively suppresses VEGFA and ANGPT1 and enhances PAX6 expression in multiple corneal epithelia, effects are variable across primary and immortalized cells. Effects of longer-term in vivo treatment, however, require further study.

Role of the transcription factor PAX3 during myogenesis: from the embryo to the adult stage

PAX3 plays a crucial role in embryonic myogenesis, controlling the specification, migration, proliferation, and differentiation of muscle progenitor cells to ensure normal skeletal muscle development in the embryo. However, PAX3 potential role in a context of muscle homeostasis and regeneration remains poorly investigated. The adult muscle stem cells, known as satellite cells (SCs) exhibit heterogeneity in Pax3 expression in various muscles throughout the body and display a bimodal response to environmental stress exposure. To explore the role of PAX3 in the context of tissue damage, we performed regeneration studies, which unveiled a functional heterogeneity of the SCs populations depending on Pax3 expression. Together, this project aims to decipher cell-type specific dysregulations linked to tissue damage and identify PAX3 downstream gene regulatory networks that can lead to specific SC behavior, thus potentially providing novel strategies for muscle disease preventive therapies.

Supraspinatus Muscle Regeneration Following Rotator Cuff Tear: A Study of the Biomarkers Pax7, MyoD, and Myogenin.

The success of rotator cuff tendon repair relies on both tendon healing and muscle recovery. The objective of this descriptive study was to investigate the regenerative potential of the supraspinatus muscle in rotator cuff tear conditions by quantifying the expression of Pax7, MyoD, and myogenin, basic factors that regulate myogenesis. Muscle biopsies were collected from thirty-three patients aged 34 to 73 years who underwent surgery for a rotator cuff tear affecting the supraspinatus muscle. Among these patients, twenty-seven percent were women, and the age of the lesions ranged from 2 to 72 months post-initial trauma. Biopsies were harvested from the supraspinatus muscle at the end closest to the tendon, and control biopsies were harvested from the ipsilateral deltoid muscle. The densities of immunohistochemically stained Pax7+, MyoD+, and myogenin+ nuclei/mm2 were used to estimate the myogenic potential of the muscle. Adjustments were made for patient age and lesion age. We found increased density of MyoD+ and myogenin+ cells in supraspinatus muscles compared to deltoid muscles (p < 0.001 and p = 0.003, respectively). Regression analyses that combined the density of positive nuclei with patient age showed a continuous increase in Pax7 with age but also a reduction of MyoD and myogenin in older patients. When combined with lesion age, there was a decline in the density of all myogenic markers after an initial rise. Pax7 density continued to be higher in supraspinatus compared to the deltoid muscle, but the density of MyoD and myogenin terminally dropped to a density lower than in the deltoid. Our findings suggest that the supraspinatus muscle in tear conditions showed signs of initial activation of muscle regeneration. When compared to the unaffected deltoid muscle, an apparent reduction in capacity to progress to full muscle fiber maturity was also demonstrated. This pattern of inhibited myogenesis seemed to increase with both patient age and lesion age. Our results on muscle regenerative capacity indicate that younger patients with rotator cuff tears have better chances of muscle recovery and may benefit from early surgical reconstruction.

SOX17 Expression in Mesotheliomas and Benign Mesothelial Proliferations: Implications for Differential Diagnosis With Gynecologic Carcinomas.

SOX17 has recently emerged as a novel immunohistochemical marker for cancers of endometrial and ovarian origin with improved specificity compared with the widely used Mullerian marker PAX8. However, evaluation of SOX17 in benign and malignant peritoneal mesothelial proliferations remains limited, and these may mimic gynecologic carcinomas, particularly on small biopsies. We evaluated SOX17 and PAX8 expression in 20 benign mesothelial lesions (5 adenomatoid tumors, 5 well-differentiated papillary mesothelial tumors, and 10 peritoneal inclusion cysts) and 16 epithelioid peritoneal mesotheliomas. The 17 female and 3 male patients with benign mesothelial lesions ranged from 20 to 80yr (median: 56.5yr), while the 9 females and 7 males with mesothelioma ranged from 47 to 85yr (median: 57.5yr). SOX17 was positive in 5 (25%) benign lesions (2 adenomatoid tumors, 3 peritoneal inclusion cysts) and 2 (13%) mesotheliomas, while PAX8 stained 8 (40%) benign lesions (1 adenomatoid tumor, 1 well-differentiated papillary mesothelial tumor, 6 peritoneal inclusion cysts), and 2 (13%) mesotheliomas. Results for the 2 stains showed incomplete concordance, with agreement in 15 (75%) benign proliferations and 14 (88%) mesotheliomas. Our findings suggest that SOX17 positivity alone is insufficient to confirm a diagnosis of gynecologic carcinoma over a mesothelial proliferation and pathologists should exercise caution when these entities are diagnostic considerations.

The Effect of Geranylgeraniol and Ginger on Satellite Cells Myogenic State in Type 2 Diabetic Rats.

Type 2 diabetes (T2D) is associated with increased inflammation and reactive oxygen species (ROS) in muscles, leading to basal satellite cell (SC) myogenic impairment (i.e., reduction in SC pool), which is critical for maintaining skeletal muscle mass. T2D may contribute to muscle atrophy, possibly due to reductions in the SC pool. Geranylgeraniol (GGOH) and ginger can reduce inflammation and enhance SC myogenesis in damaged muscles, thereby alleviating muscle atrophy; however, their effect on basal SC myogenic state and muscle mass in T2D rats is limited. Rats consumed a control diet (CON), high-fat diet with 35 mg/kg of streptozotocin (HFD), a HFD with 800 mg/kg body weight of GGOH (GG), or a HFD with 0.75% ginger root extract (GRE). In the eighth week, their soleus muscles were analyzed for Pax7, MyoD, and MSTN gene and protein expression, SC myogenic state, and muscle cross-sectional area (CSA). The HFD group had a significantly lower number of Pax7+/MyoD- and Pax7+/MSTN+ cells, less Pax7 and MyoD gene expression, and less MyoD and MSTN protein expression, with a smaller CSA than the CON group. Compared to the GG and GRE groups, the HFD group had a significantly lower number of Pax7+/MSTN+ cells, less MyoD protein expression, and smaller CSA. The GRE group also had a significantly lower number of Pax7-/MyoD+ and greater MSTN protein expression than the HFD group. Nevertheless, the CON group had a significantly greater number of Pax7+/MyoD- than the GG and GRE groups, and a greater number of Pax7-/MyoD+ cells than the GRE group with a larger CSA than the GG group. GGOH and ginger persevered muscle CSA, possibly through increased MyoD and the ability to maintain the SC pool in T2D rats.

Gastric and Gastrointestinal-like Immunophenotypes In Conventional Endometrial Endometrioid Adenocarcinomas Including Endometrioid Adenocarcinomas with Mucinous Differentiation: Frequency and Diagnostic Implications

Abstract Introduction/Objective Mucinous carcinomas of the gastric/gastrointestinal type (MCG) are now recognized as a rare, clinically aggressive subtype of endometrial cancer [EMCa]. However, neither their full morphologic spectrum, nor their defining immunophenotype, has been clearly defined. Previous proposals for their recognition include at least focal immunohistochemical expression of gastrointestinal markers, minimality or absence of ER and possibly PAX8 expression, and the absence of an endometrioid carcinoma component. Herein, we assess the frequency of gastric and gastrointestinal immunophenotypes in conventional endometrioid carcinomas without any discernible gastric/gastrointestinal-type morphology. Methods/Case Report Immunohistochemical analyses for CK7, CK20, CDX2, ER, SATB2, MUC6, PAX8 were performed on 81 EMCa, comprised of consecutively archived cases of low grade endometrioid carcinoma (n=47), FIGO grade III endometrioid carcinoma (n=12), and endometrioid carcinomas with mucinous differentiation (n=22). None showed goblet cells or gastric-type morphology. Expression levels were quantified as H-scores on a standardized 0-300 scale. Results (if a Case Study enter NA) Significant subsets of all 3 groups showed expression of MUC6, CDX2, SATB2 and CK20, without any significant differences between the groups. 56%, 62%, 23% and 25% of cases expressed MUC6, CDX2, CK20 and SATB2 respectively. 37% co-expressed MUC6 and CDX2, 12% co-expressed CDX2 and CK20, 6% co-expressed MUC6, CDX2 and CK20 and 2.5% co-expressed CDX2, CK20 and SATB2. The expression levels were generally low across all groups, with average H scores for positive cases being 49.5 [range 1-250] for MUC6, 33.7 [range 1-285] for CDX2, 24.0 [range 1-270] for CK20, and 30.5 [range; 2-220] for SATB2. There was no statistically significant correlation between the expression of any of the 4 markers (CK20, CDX2, SATB2 or MUC6) and low ER or PAX8 expression. However, the only 2 cases with high CDX2 expression (H: &amp;gt;/=200) were also associated with low ER (H&amp;lt;50) expression, and one of these concurrently showed high CK20 (H: 270) and low PAX8 (H: 2) expression, suggestive of true intestinal differentiation. Conclusion MUC6, SATB2, CDX2, and CK20 are not uncommonly expressed at low levels in endometrioid carcinoma. As such, the expression of these markers cannot be the sole basis for defining the clinically aggressive EMCa with true gastric/gastrointestinal differentiation, and for distinguishing them from conventional endometrioid carcinomas.