Expression Of Sox2 Research Articles

The essential role of the miRNA-208a/TARBP2/Sox6 axis in myosin expression in the end stage human heart failure

Abstract Despite diverse aetiologies, failing human hearts (HF) of various origins (coronary artery disease (CAD), dilated cardiomyopathy (DCM), restrictive cardiomyopathy, and hypertrophic cardiomyopathy (HCM)) exhibit impaired contractility and share alterations in MYH6, MYH7, and MYH7B gene expression. Here, we explore the miRNA-208a/TARBP2/Sox6 axis in regulating myosin expression within left ventricles of explanted human hearts. Methods Samples of left ventricles were obtained from explanted hearts of patients with terminal HF (NYHA III-IV) and reduced left ventricle ejection fraction (LVEF <25%) due to CAD (n=10), DCM (n=10), HCM (n=6), and controls (n=5). We analysed the expression of cardiac myosin heavy chains (MYH6, MYH7, MYH7B), cardiac damage markers (ANP, BNP), and heart-related MyoMiRs using quantitative real-time PCR. Results Pre-transplant data for the 31 subjects (25 male, 3 female) included: age 54.4±8.2y, BP 112±18/67±11 mmHg, HR 79±16 min-1, LVEF 27±14%, LVEDD 8.8±15.8mm, RVEDD 32.8±5.1mm, QRS 0.140±0.05s, QT 0.42±0.04s, NT-proBNP 5551±4259 ng/l. In all diseased groups, MYH6 mRNA was downregulated, while MYH7 and MHRT ncRNA were upregulated. We observed strong positive correlations between MYH7, MYH7B, and MHRT transcription, suggesting coordinated expression. The miRNA-208a/miRNA-208b ratio shifted heavily towards miRNA-208b in controls, with a similar effect for miRNA-499 and MYH7B. A strong negative correlation existed between miRNA-499 and MYH7B expression across HF samples. TARBP2 expression decreased slightly in all pathological groups, while Sox6 mRNA increased. Conclusion Elevated Sox6 expression may contribute to MYH6 downregulation and MYH7/MYH7B upregulation. Altered TARBP2 expression could promote cardiomyopathy via Sox6-mediated repression of cardiac slow-twitch myofiber proteins. Changes in miRNA-208a processing leading to Sox6 upregulation may inhibit Sox6-dependent myosin transcript expression.

Characterization of E-Cadherin, SSEA-1, MSI-1, and SOX-2 Expression and Their Association with Pale Cells in Adenomyosis

Adenomyosis (AM) is a gynecological disease characterized by the invasion of endometrial glands and stroma within the myometrium. The etiology and pathogenesis of AM remain inadequately understood. Pale cells were identified as a novel cell type characterized by the absence of desmosomal contacts and light-colored cytoplasm. These cells were observed to migrate individually through ultra-micro ruptures in the basal membrane of the endometrial glands, translocating into the stroma and then further into the myometrium. Our study aimed to explore the possible stem cell properties of these pale cells. Forty hysterectomy specimens were analyzed using immunohistochemistry and immunofluorescence to assess negative E-cadherin expression and the positive expression of stem cell markers SSEA-1, MSI-1, and SOX-2. Immunohistochemical analysis revealed the presence of pale cells and occasionally rounded, enlarged E-cadherin-negative cells predominantly in the basal endometrial epithelium. The stem cell marker SSEA-1 was significantly elevated in the basalis epithelium, as well as in the ectopic epithelium. SSEA-1 positive cells were also identified in the stroma and myometrium. Sporadic colocalization of SSEA-1+/E-cadherin– cells was confirmed through immunofluorescence. The positive staining of pale cells for SSEA-1 and MSI-1 was also confirmed at the ultrastructural level by immunoelectron microscopy. These findings indicate that pale cells may possess stem cell characteristics, particularly a positive SSEA-1 profile, warranting further in vitro investigation into their role in the pathogenesis of adenomyosis.

Construction of a tumor mutational burden-derived LncRNA prognostic computational framework associated with therapy sensitivity in skin cutaneous melanoma

BackgroundSkin cutaneous melanoma (SKCM) poses a significant public health challenge due to its aggressive nature and limited treatment options. To address this, the study introduces the Tumor Mutational Burden-Derived Immune lncRNA Prognostic Index (TILPI) as a potential prognostic tool for SKCM.MethodsTILPI was developed using a combination of gene set variation analysis, differential expression analysis, and COX regression analysis. Additionally, functional experiments were conducted to validate the findings, focusing on the effects of STARD4-AS1 knockdown on SKCM tumor cell behavior. These experiments encompassed assessments of tumor cell proliferation, gene and protein expression, migration, invasion, and in vivo tumor growth.ResultsThe results demonstrated that knockdown of STARD4-AS1 led to a significant reduction in tumor cell proliferation and impaired migration and invasion abilities. Moreover, it resulted in the downregulation of ADCY4, PRKACA, and SOX10 gene expression, as well as decreased protein expression of ADCY4, PRKACA, and SOX10. In vivo experiments further confirmed the efficacy of STARD4-AS1 knockdown in reducing tumor growth.ConclusionsThis study elucidates the mechanistic role of STARD4-AS1 and its downstream targets in SKCM progression, highlighting the importance of the ADCY4/PRKACA/SOX10 pathway. The integration of computational analysis with experimental validation enhances the understanding of TILPI and its clinical implications. Overall, the findings underscore the potential of novel computational frameworks like TILPI in predicting and managing SKCM, particularly through targeting the ADCY4/PRKACA/SOX10 pathway.

Cellular senescence contributes to spontaneous repair of the rat meniscus.

Cellular senescence, traditionally associated with aging and chronic diseases, has recently been identified as a potential facilitator of tissue regeneration via a senescence-associated secretory phenotype (SASP). In rodents, the meniscus is known to regenerate spontaneously from the surrounding synovium, but the mechanism, and especially its relationship to cellular senescence, remains unclear. This study investigated the contribution of cellular senescence to spontaneous repair of the rat meniscus. We created a rat partial medial meniscectomy (pMx) model to evaluate time-course changes in regenerative tissue. Immunohistochemistry revealed marked increases in p16 expression and senescence-associated beta-galactosidase (SA-β-gal) activity in the regenerating tissue at the early phase after pMx surgery. RNA sequencing of regenerating tissues identified the upregulation of genes related to aging, extracellular matrix organization, and cell proliferation. Fluorescence staining identified high expression of SOX9, a master regulator of cartilage/meniscus development, adjacent to p16-positive cells. Invitro investigations of the effect of SASP factors on synovial fibroblasts (SFs) demonstrated that conditioned medium from senescent SFs stimulated the proliferation and chondrogenic differentiation of normal SFs. Invivo histological evaluation to determine whether selective elimination of senescent cells with a senolytic drug (ABT-263) retarded spontaneous repair of meniscus invivo confirmed that ABT-263 decreased the meniscus score and expression of SOX9, aggrecan, and type 1 collagen. Our findings indicate that transient senescent cell accumulation and SASP in regenerating tissues beneficially contribute to spontaneous repair of the rat meniscus. Further research into the molecular mechanism will provide a novel strategy for meniscus regeneration based on cellular senescence.

Feedback loop LINC00511-YTHDF2-SOX2 regulatory network drives cholangiocarcinoma progression and stemness.

Cholangiocarcinoma (CCA) was identified as a malignant tumor with rising incidence and mortality rates, and the roles of long noncoding RNA (lncRNA) in CCA remained not entirely clear. In this study, LINC00511 had high expression in CCA, which was closely related to poor prognosis. Knockdown of LINC00511 significantly inhibited cell malignant biological behaviors. It also affected the stemness of CCA, evidenced by decreased SOX2 protein expression. Moreover, the study revealed the interaction of LINC00511, YTHDF2, and SOX2 in CCA. Specifically, LINC00511 facilitated the formation of a complex with YTHDF2 on SOX2 mRNA, which uniquely enhances the mRNA's stability through m6A methylation sites. This stabilization appears crucial for maintaining malignant behaviors in CCA cells. Additionally, LINC00511 modulated SOX2 expression via the PI3K/AKT signaling pathway. Meanwhile, SOX2 can also promote LINC00511 expression as an upstream transcription factor, thereby confirming a positive feedback loop formed by LINC00511, YTHDF2, and SOX2, which plays a significant role in the occurrence and development of CCA. Finally, the study successfully constructed two patient-derived xenograft models, revealing the vital role of LINC00511 in CCA development. In summary, this research provides a comprehensive understanding of the role of LINC00511 in the pathogenesis of CCA.

Suppressing DUSP16 overexpression induced by ELK1 promotes neural progenitor cell differentiation in mouse models of Alzheimer's disease.

Emerged evidence indicated that stimulating hippocampal neurogenesis is a potential strategy for restoring cognition in AD. Mitogen-activated protein kinases (MAPKs) play an essential role in neurogenesis. Meanwhile, the enzymatic power of the phosphatases is much greater than that of kinases. Dual-specificity phosphatase 16 (DUSP16), known to as a phosphatase negatively regulate MAPKs, may be implicated in neural differentiation. Nevertheless, the effect of DUSP16 on cognitive disorders by stimulating neural progenitor cell (NPC) differentiation in AD mice remains unclear. Our study demonstrates an association between DUSP16 SNPs and clinical progression in individuals with mild cognitive impairment (MCI). Besides, increased DUSP16 expression was detected in both 3xTg and SAMP8 mouse models of AD, accompanied by NPC neural differentiation impairments. By silencing DUSP16, the induction of neural differentiation, synaptic transmission, and cognitive benefits were observed in both AD mice. Furthermore, DUSP16 was involved in the process of NPC differentiation through regulating c-Jun N-terminal kinase (JNK) phosphorylation and SOX2 expression. Moreover, ETS transcription factor (ELK1) was involved in the DUSP16 transcription, which resulted in the upregulation of DUSP16 at the state of AD. Our data uncovers a potential regulatory role for DUSP16 in adult hippocampal neurogenesis (AHN) and provides a possibility to find a novel strategy for AD intervention.

Up-Regulation of miR-625-5p Correlates with Suppressed Sox2, Increased Apoptosis, and Cell Cycle Arrest via The PI3K/AKT Signalling Pathway in Acute Myeloid Leukaemia

Background: Up-regulation of the microRNA-625 and abnormal expression of the Sox2 gene have been studied and seen in several tumors. Few reports have also shown the aberrant expression of miR-625 and Sox2 expression in various cancers. Several studies have also confirmed that phosphatidylinositol 3' -kinase /protein kinase B pathways regulate hematological malignancies, including Acute Myeloid Leukemia (AML). Thus, this study aimed to investigate the effects of mir-625 up-regulation on proliferation, apoptosis, and cell cycle by targeting the Sox2 gene via the downstream Akt signaling pathway and cell cycle regulators, such as p21, p27, and cyclin E in the KG-1 cell line. Materials and Methods: Cells obtained from the KG-1 cell line were cultured and transfected with plasmid DNA (miR-625) and scrambled as the control using the Lonza electroporation system. Flow cytometry was used to evaluate cell cycle, proliferation, and apoptosis. Relative gene expression was validated by qRT-PCR. All data were analyzed using graph pad prism 7.01 and REST 2009. Results: KG-1 cells transfected with the mir625-GFP construct showed decreased proliferation, increased apoptosis, and induced cell cycle arrest. Low levels of Sox2, p21, cyclin E, and up-regulation of p27 were confirmed and validated by qRT-PCR ( P < 0.05 ). Conclusion: MiR-625 can be a promising approach to aid in the treatment of AML. However, further studies are required in this field

Downregulation of Krüppel-like factor 15 expression delays endochondral bone ossification during fracture healing

ObjectiveThe role of Krüppel-like zinc finger transcription factor 15 (KLF15) in endochondral ossification during fracture healing remains unexplored. In this study, we aimed to elucidate the impact of KLF15 in a mouse model of tibial transverse fracture. MethodsWe created tamoxifen-inducible, cartilage-specific KLF15 knockout mice (KLF15 KO). KLF15 fl/fl Col2-CreERT mice from the same litters as the KLF15 KO mice, but not treated with 4-hydroxytamoxifen, were used as controls (CT). At 10 weeks, male KLF15 KO and CT mice underwent tibial fracture followed by intramedullary nailing. Both groups were administered tamoxifen at days 0, 3, and 7 after surgery. The tibiae were harvested on post-surgery days 7, 10, and 14 for radiological assessment using micro-computed tomography. Histological staining (Safranin-O) and immunohistochemistry for KLF15, SOX9, Indian hedgehog (IHH), RUNX2, and Osterix were performed. Additionally, cartilage from mouse fetus was cultured for qRT-PCR and western blot analyses of KLF15, SOX9, IHH, Col2, RUNX2, Osterix, TGF-β, SMAD3, and phosphor-SMAD3. ResultsThe radiological assessment revealed that immature callus formation was delayed in KLF15 KO, compared with that in CT, peaking on day 14 compared with that on day 10 in CT. KLF15 KO mice exhibited delayed fracture healing and reduced Safranin-O staining at days 7 and 10 post-surgery. The ratio of cells positive for KLF15 and SOX9 was significantly lower in KLF15 KO than in CT, whereas the ratios for IHH, RUNX2, and Osterix showed no significant difference. RT-PCR revealed reduced expression of KLF15, SOX9, and COL2, with no significant changes in IHH, Osterix, RUNX2, TGF-β, and SMAD3. Western blot analysis indicated decreased SMAD3 phosphorylation in KLF15 KO mice. ConclusionKLF15 regulates SOX9 via the TGF-β-SMAD3-SOX9 pathway, independent of IHH, in endochondral ossification. The KLF15 deficiency decreases SOX9 expression through reduced SMAD3 phosphorylation, subsequently delaying fracture healing.

Regulatory mechanism of DDX5 in ox-LDL-induced endothelial cell injury through the miR-640/SOX6 axis.

Endothelial dysfunction is an early and pre-clinical manifestation of coronary heart disease (CHD). This study investigates the role of DDX5 in oxidized low-density lipoprotein (ox-LDL)-induced endothelial cell injury to confer novel targets for the treatment of CHD. Endothelial cells were induced by ox-LDL. DDX5, pri-miR-640, pre-miR-640, miR-640, and SOX6 expressions were analyzed by RT-qPCR and Western blot. DDX5 expression was intervened by shRNA, followed by CCK-8 analysis of proliferation, flow cytometry detection of apoptosis, and tube formation assay analysis of angiogenic potential of cells. The binding between DDX5 and pri-miR-640 was determined by RIP, and the pri-miR-640 RNA stability was measured after actinomycin D treatment. Dual-luciferase assay verified the targeting relationship between miR-640 and SOX6. DDX5 and miR-640 were highly expressed while SOX6 was poorly expressed in ox-LDL-induced endothelial cells. Silence of DDX5 augmented cell proliferation, abated apoptosis, and facilitated angiogenesis. Mechanistically, RNA binding protein DDX5 elevated miR-640 expression by weakening the degradation of pri-miR-640, thereby reducing SOX6 expression. Combined experimental results indicated that overexpression of miR-640 or low expression of SOX6 offset the protective effect of DDX5 silencing on cell injury. DDX5 elevates miR-640 expression by repressing the degradation of pri-miR-640 and then reduces SOX6 expression, thus exacerbating ox-LDL-induced endothelial cell injury.

TGF-β induces an atypical EMT to evade immune mechanosurveillance in lung adenocarcinoma dormant metastasis.

The heterogeneity of epithelial-to-mesenchymal transition (EMT) programs is manifest in the diverse EMT-like phenotypes occurring during tumor progression. However, little is known about the mechanistic basis and functional role of specific forms of EMT in cancer. Here we address this question in lung adenocarcinoma (LUAD) cells that enter a dormancy period in response to TGF-β upon disseminating to distant sites. LUAD cells with the capacity to enter dormancy are characterized by expression of SOX2 and NKX2-1 primitive progenitor markers. In these cells, TGF-β induces growth inhibition accompanied by a full EMT response that subsequently transitions into an atypical mesenchymal state of round morphology and lacking actin stress fibers. TGF-β induces this transition by driving the expression of the actin-depolymerizing factor gelsolin, which changes a migratory, stress fiber-rich mesenchymal phenotype into a cortical actin-rich, spheroidal state. This transition lowers the biomechanical stiffness of metastatic progenitors, protecting them from killing by mechanosensitive cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells. Inhibiting this actin depolymerization process clears tissues of dormant metastatic cells. Thus, LUAD primitive progenitors undergo an atypical EMT as part of a strategy to evade immune-mediated elimination during dormancy. Our results provide a mechanistic basis and functional role of this atypical EMT response of LUAD metastatic progenitors and further illuminate the role of TGF-β as a crucial driver of immune evasive metastatic dormancy.

EPIGENETIC MODULATION OF STEMNESS AND DIFFERENTIATION BY VALPROIC ACID IN MEDULLOBLASTOMA

Abstract AIMS Changes in epigenetic processes, including histone acetylation, are proposed as key events affecting tumor cell function and the initiation and progression of pediatric brain cancers. Valproic acid (VPA) is an antiepileptic drug that acts partially by inhibiting histone deacetylases (HDACs) and could be repurposed as an epigenetic anticancer therapy. Here, we report VPA-induced alterations in features related to stemness and differentiation in medulloblastoma (MB) cells. METHOD Human MB cells were treated with different concentrations of VPA and cell viability was measured with a trypan exclusion assay. Cell cycle was evaluated with flow cytometry. Expansion of MB cancer stem cells (CSCs) was evaluated by a neurosphere formation assay. Reverse transcriptase polymerase chain reaction (RT-qPCR) was used to analyze mRNA expression and Western Blot to analyze protein levels. H3K9 histone acetylation (H3K9ac) was measured with immunofluorescence, and chromatin Immunoprecipitation (ChIP) was used to evaluate the occupancy of gene promoter regions by H3K9ac. RESULTS VPA reduced MB cell viability and expansion of MB CSCs, induced morphological changes consistent with neuronal differentiation, and increased expression of differentiation markers tubulin beta 3 class III (TUBB3) and enolase 2 (ENO2). Expression of stemness markers SOX2 and Nestin was differentially affected by VPA in cells representative of SHH or Group 3/4 MB molecular subgroups. VPA increased H3K9ac and its occupancy of promoter regions of TP53 and CDKN1A genes. CONCLUSION Our results indicate that VPA may exert antitumor effects in MB by influencing histone acetylation, which may result in modulation of stemness and stimulation of neuronal differentiation.

SOX17 expression in tumor-penetrating vessels in relation to CD8+ T-cell infiltration in cancer stroma niches.

Sex-determining region Y-related high-mobility group box 17 protein (SOX17), a proangiogenic transcription factor, is specifically expressed in tumor endothelial cells (TECs) of implanted Lewis lung carcinoma. However, the expression profile of SOX17 is largely unknown in human lung cancer. We aimed to elucidate SOX17 expression in cancer cells and the tumor microenvironment of lung adenocarcinoma. In the present study, we examined SOX17 expression in whole-tissue specimens of 83 lung adenocarcinomas by immunohistochemistry. SOX17 immunoreactivity was minimal in lung adenocarcinoma cells, except in five non-mucinous adenocarcinomas in situ. SOX17 was also expressed in cultured A549 lung adenocarcinoma cells, which is widely used as a model of malignant alveolar type II epithelial cells. Notably, SOX17 immunoreactivity was found in endothelial cells of tumor-penetrating vessels in 19 of 83 lung adenocarcinoma tissue specimens, with statistical significance to stromal infiltration of CD8+ T cells (p < 0.01) but was not associated with the number of tertiary lymph nodes. Although not statistically significant, SOX17 immunoreactivity was related to favorable patient outcomes. Our findings indicate that SOX17 might play a pleiotropic role in lung adenocarcinoma in cancer cells and stromal niches. SOX17-mediated CD8+ T-cell-rich tumor microenvironment might attract interest in improving the effect of cancer immunotherapy.

Protective Effect of Mesenchymal Stem Cells and Melatonin on Testicular Torsion-Induced Infertility

We aimed to explore the effects of systemic melatonin and intratesticular Adipose tissue-derived mesenchymal stem cells (AdMSCs) administration on rats with acute unilateral testicular torsion. Rats were randomized into Sham group (S) (n=8), torsion/detorsion group (T/D by torsion of right testis with rotated 720° counter clockwise for 3 h, then detorsion) (n=8), Melatonin group given 25 mg/kg after torsion/detorsion (M) (n=8), Adipose tissue-derived mesenchymal stem cell-treated group after torsion/detorsion (MSC) (n=8), Adipose tissue-derived mesenchymal stem cell-treated group with melatonin after torsion/detorsion (MSC+M) (n=8). We measured MDA, Testosterone, FSH and LH levels, performed histopathological analyses in testicles, and identified SOX, VASA and Caspas-3 reactions immunohistochemically. Testosterone, FSH, LH values did not yield any significant difference between the groups. While the Johnson score in the right testis remained the lowest in T/D, the highest score was noted in the S. The T/D manifested some degenerative seminiferous tubules, abnormal spermatogenesis and maturation arrest. The degenerative appearance monitored in M, MSC and MSC+M groups persisted in some tubules, while markedly reduced degeneration was observed in some other tubules. The highest Caspase-3 expression in T/D, whereas SOX-9 expression remained significantly higher in the treatment groups. Another aspect deserving attention is that MSC were characterized by low VASA expression. Our experimental trial suggests that the torsion-induced degeneration in testicular tissue was ameliorated in all the treatment groups. Although MSC, MSC+M and M administrations decreased the torsion-induced degeneration in the testicular tissue, these treatments did not prove to be superior to each other.

MIAT promotes myofibroblastic activities and transformation in oral submucous fibrosis through sponging the miR-342-3p/SOX6 axis.

Oral submucous fibrosis (OSF) is an oral potentially malignant disorder that is closely related to the habit of areca nut chewing. Long non-coding RNA (lncRNA) myocardial infarction-associated transcript (MIAT) has been identified as an essential regulator in the fibrosis progression. However, the role of MIAT in the development of OSF remains unknown. The transcriptomic profile showed that MIAT is significantly overexpressed in the OSF cohort, with a positive correlation to fibrotic markers. The silencing of MIAT expression in primary buccal mucosal fibroblasts (BMFs) markedly inhibited arecoline-induced myofibroblast transformation. Mechanistically, MIAT functioned as a miR-342-3p sponge and suppressed the inhibitory effect of miR-342-3p on SOX6 mRNA, thereby reinstating SOX6 expression. Subsequent RNA expression rescue experiments confirmed that MIAT enhanced resistance to apoptosis and facilitated myofibroblastic properties such as cell mobility and collagen gel contraction by regulating the miR-342-3p/SOX6 axis. Taken together, these results suggest that the abnormal upregulation of MIAT is important in contributing persistent activation of myofibroblasts in fibrotic tissue, which may result from prolonged exposure to the constituents of areca nut. Furthermore, our findings demonstrated that therapeutic avenues that target the MIAT/miR-342-3p/SOX6 axis may be a promising approach for OSF treatments.

8796 Increased Sertoli Cell Proliferation in FSTL3 Deleted Mouse Testis

Abstract Disclosure: R. Ballesteros: None. A. Mukherjee: None. Activin, a TGFβ ligand, plays key roles in Sertoli cell proliferation. Follistatin like 3 (FSTL3) is a glycoprotein inhibitor of activin expressed strongly in the testis. We have shown that FSTL3 deletion (FSTL3 KO) in mice increases testicular size, likely caused by increased spermatogenesis supported by the increased Sertoli cell numbers seen in FSTL3 KO mouse testes. It is not clear, however, whether there is increased proliferation of Sertoli cells postnatally. We, therefore, investigated Sertoli cell proliferation, and molecular pathways that might be activated upon FSTL3 deletion that lead to increased Sertoli cell proliferation in mice. Paired testes weight comparison indicates that there is significant increase in testicular mass in FSTL3 KO between 28d and 56d coinciding with the onset of continued spermatogenesis. Immunofluorescence studies using PCNA as marker for proliferation and SOX9 to identify Sertoli cells, however, found no significant differences between proliferation of Sertoli cells in WT and FSTL3 KO. BrdU injection of mice followed by immunofluorescence labelling of proliferating Sertoli cells also showed no difference between the two genotypes by immunofluorescence. We then proceeded to assess whether there is an alteration of differentiation in FSTL3 KO testes to test the possibility that instead of proliferation there is an increased differentiation of a pre-Sertoli like cell in FSTL3 KO mice using WT1 and SOX9 as markers for early or late Sertoli cells. This experiment revealed that there was no difference between the ratio of WT1 and SOX9 expression in the two genotypes. Flow cytometric analyses using testicular dispersates from mice using Sox9 and Ki67 antibodies to identify proliferating Sertoli cells, however, revealed an approximately two-fold increase in proliferating Sertoli cells in FSTL3 KO compared to WT at 7d. At 56d there were very few proliferating Sertoli cells in either genotype and there was no difference in this number in FSTL3 deleted mice compared to WT. mRNA sequence analysis showed that approximately 1000 genes are differentially regulated between WT and FSTL3 KO at 3d. Gene ontology and pathway analysis revealed that a constellation of meiosis related genes and activin signalling pathway, among others, are enriched in FSTL3 KO testis at this stage. Data presented here demonstrates that FSTL3 deletion induces activin receptor signalling pathway, genes crucial for meiosis and therefore the spermatogenic process, and Sertoli cell proliferation. This opens the possibility that the early arrest of Sertoli cell proliferation seen in mammals including mice and humans might be circumvented by inactivating FSTL3. This could then lead to a therapeutic angle in male infertility that are based on paucity of Sertoli cells. It will be important to address why FSTL3 deletion induces Sertoli cell proliferation only postnatally but not post pubertally. Presentation: 6/1/2024

8796 Increased Sertoli Cell Proliferation in FSTL3 Deleted Mouse Testis

Abstract Disclosure: R. Ballesteros: None. A. Mukherjee: None. Activin, a TGFβ ligand, plays key roles in Sertoli cell proliferation. Follistatin like 3 (FSTL3) is a glycoprotein inhibitor of activin expressed strongly in the testis. We have shown that FSTL3 deletion (FSTL3 KO) in mice increases testicular size, likely caused by increased spermatogenesis supported by the increased Sertoli cell numbers seen in FSTL3 KO mouse testes. It is not clear, however, whether there is increased proliferation of Sertoli cells postnatally. We, therefore, investigated Sertoli cell proliferation, and molecular pathways that might be activated upon FSTL3 deletion that lead to increased Sertoli cell proliferation in mice. Paired testes weight comparison indicates that there is significant increase in testicular mass in FSTL3 KO between 28d and 56d coinciding with the onset of continued spermatogenesis. Immunofluorescence studies using PCNA as marker for proliferation and SOX9 to identify Sertoli cells, however, found no significant differences between proliferation of Sertoli cells in WT and FSTL3 KO. BrdU injection of mice followed by immunofluorescence labelling of proliferating Sertoli cells also showed no difference between the two genotypes by immunofluorescence. We then proceeded to assess whether there is an alteration of differentiation in FSTL3 KO testes to test the possibility that instead of proliferation there is an increased differentiation of a pre-Sertoli like cell in FSTL3 KO mice using WT1 and SOX9 as markers for early or late Sertoli cells. This experiment revealed that there was no difference between the ratio of WT1 and SOX9 expression in the two genotypes. Flow cytometric analyses using testicular dispersates from mice using Sox9 and Ki67 antibodies to identify proliferating Sertoli cells, however, revealed an approximately two-fold increase in proliferating Sertoli cells in FSTL3 KO compared to WT at 7d. At 56d there were very few proliferating Sertoli cells in either genotype and there was no difference in this number in FSTL3 deleted mice compared to WT. mRNA sequence analysis showed that approximately 1000 genes are differentially regulated between WT and FSTL3 KO at 3d. Gene ontology and pathway analysis revealed that a constellation of meiosis related genes and activin signalling pathway, among others, are enriched in FSTL3 KO testis at this stage. Data presented here demonstrates that FSTL3 deletion induces activin receptor signalling pathway, genes crucial for meiosis and therefore the spermatogenic process, and Sertoli cell proliferation. This opens the possibility that the early arrest of Sertoli cell proliferation seen in mammals including mice and humans might be circumvented by inactivating FSTL3. This could then lead to a therapeutic angle in male infertility that are based on paucity of Sertoli cells. It will be important to address why FSTL3 deletion induces Sertoli cell proliferation only postnatally but not post pubertally. Presentation: 6/1/2024

Surrogate Immunohistochemical Markers of Proliferation and Embryonic Stem Cells in Distinguishing Ameloblastoma from Ameloblastic Carcinoma

PurposeThe current study aimed to investigate the use of surrogate immunohistochemical (IHC) markers of proliferation and stem cells to distinguish ameloblastoma (AB) from ameloblastic carcinoma (AC).MethodsThe study assessed a total of 29 ACs, 6 ABs that transformed into ACs, and a control cohort of 20 ABs. The demographics and clinicopathologic details of the included cases of AC were recorded. The Ki-67 proliferation index was scored through automated methods with the QuPath open-source software platform. For SOX2, OCT4 and Glypican-3 IHC, each case was scored using a proportion of positivity score combined with an intensity score to produce a total score.ResultsAll cases of AC showed a relatively high median proliferation index of 41.7%, with statistically significant higher scores compared to ABs. ABs that transformed into ACs had similar median proliferation scores to the control cohort of ABs. Most cases of AC showed some degree of SOX2 expression, with 58.6% showing high expression. OCT4 expression was not seen in any case of AC. GPC-3 expression in ACs was limited, with high expression in 17.2% of ACs. Primary ACs showed higher median proliferation scores and degrees of SOX2 and GPC-3 expression than secondary cases. Regarding SOX2, OCT4 and GPC-3 IHC expression, no statistically significant differences existed between the cohort of ABs and ACs.ConclusionKi-67 IHC as a proliferation marker, particularly when assessed via automated methods, was helpful in distinguishing AC from AB cases. In contrast to other studies, surrogate IHC markers of embryonic stem cells, SOX2, OCT4 and GPC-3, were unreliable in distinguishing the two entities.

Hypoxia regulate developmental coronary angiogenesis potentially through VEGF-R2- and SOX17-mediated signaling.

The development of coronary vessels in embryonic mouse heart involves various progenitor populations, including sinus venosus (SV), endocardium, and proepicardium. ELA/APJ signaling is known to regulate coronary growth from the SV, whereas VEGF-A/VEGF-R2 signaling controls growth from the endocardium. Previous studies suggest hypoxia might regulate coronary growth, but its specific downstream pathways are unclear. In this study, we further investigated the role of hypoxia and have identified SOX17- and VEGF-R2-mediated signaling as the potential downstream pathways in its regulation of developmental coronary angiogenesis. HIF-1α stabilization by knocking out von Hippel Lindau (VHL) protein in the myocardium (cKO) disrupted normal coronary angiogenesis in embryonic mouse hearts, resembling patterns of accelerated coronary growth. VEGF-R2 expression was increased in coronary endothelial cells under hypoxia in vitro and in VHL cKO hearts in vivo. Similarly, SOX17 expression was increased in the VHL cKO hearts, while its knockout in the endocardium disrupted normal coronary growth. These findings provide further evidence that hypoxia regulates developmental coronary growth potentially through VEGF-R2 and SOX17 pathways, shedding light on mechanisms of coronary vessel development.

Spitz melanoma with MAP3K8::ABLIM1 rearrangement: a case report with review of the literature

BackgroundSpitz tumors are relatively uncommon melanocytic lesions, typically affecting a relatively younger population but can be encountered at any age. They are characterized by a proliferation of melanocytes with epithelioid and/or spindled cytomorphology features, and interpretation is often challenging. The majority of these tumors are driven by kinase fusions or HRAS mutations. MAP3K8 fusions, although rare, are characteristic genomic events in Spitz tumors, especially in more atypical or malignant lesions.Case presentationHere, we present the case of a 43-year-old woman with a clinically cystic mass in her right groin, histologically characterized as a spindle and epithelioid cell malignant tumor. Immunohistochemistry revealed diffuse expression of S100 protein, tyrosinase and SOX10, patchy weak PRAME, HMB45 and Melan-A reactivity, and negative staining for BRAF V600E. Next-generation sequencing analysis revealed the presence of a MAP3K8::ABLIM1 fusion gene, as well as GRIN2A and TERT promoter mutations. The morphology, immunohistochemistry and molecular analysis confirmed Spitz melanoma with molecular features suggesting a worse prognosis.ConclusionThis case introduces a novel fusion partner of MAP3K8 in the context of Spitz melanoma and expands the morphologic and molecular spectrum of Spitz melanoma.

Overexpression of NOP58 Facilitates Proliferation, Migration, Invasion, and Stemness of Non-small Cell Lung Cancer by Stabilizing hsa_circ_0001550.

NOP58 ribonucleoprotein (NOP58) is associated with the recurrence of lung adenocarcinoma. Few investigations concentrate on the role of NOP58 in non-small cell lung cancer (NSCLC), which is the focus of our current study. Following transfection, the proliferation, migration, and invasion of NSCLC cells were assessed by 5- ethynyl-2'-deoxyuridine (EdU), wound healing, and transwell assays. The percentage of CD9+ cells was evaluated by flow cytometry assay. Based on target genes and binding sites predicted through bioinformatics analysis, a dual-luciferase reporter assay was performed to verify the targeting relationship between hsa_circ_0001550 and NOP58. The effect of NOP58 overexpression on hsa_circ_0001550 stability was gauged using Actinomycin D. The hsa_circ_0001550 and NOP58 expression levels, as well as protein expressions of CD44, CD133, OCT4, and SOX2 in NSCLC cells were determined by quantitative real-time PCR and Western blot, respectively. Hsa_circ_0001550 was remarkably up-regulated in NSCLC cell lines A549 and PC9, silencing of which weakened cell abilities to proliferate, migrate and invade, decreased CD9+ cell ratio, and diminished protein expressions of CD44, CD133, OCT4, and SOX2. NOP58 could bind to hsa_circ_0001550 and stabilize its expression, and NOP58 overexpression partially abrogated hsa_circ_0001550 knockdown-inhibited NSCLC cell proliferation, migration, invasion and stemness. Overexpression of NOP58 facilitates proliferation, migration, invasion, and stemness of NSCLC cells by stabilizing hsa_circ_0001550, hinting that NOP58 is a novel molecular target for NSCLC therapy.