Smooth Muscle Differentiation Research Articles

Histologic and immunohistochemical analysis of connective tissue changes in patients with intestinal sutures failure

Objective. To determine the role of connective tissue pathology in the development of intestinal suture failure in order to improve the results of treatment of patients with this complication. Materials and methods. The study included 45 patients with intestinal suture failure who were treated at the Shalimov National Research Center for Surgery and Transplantation of the National Academy of Medical Sciences of Ukraine in 2017–2023. Results. A comprehensive study of fragments of small and large intestine tissues revealed similar morphological changes in patients with phenotypic signs of undifferentiated connective tissue dysplasia and intestinal sutures failure. Immunohistochemical examination of tissues with monoclonal antibodies to α–smooth muscle actin in both groups of patients revealed uneven, focal expression in smooth muscle differentiation cells and fibroblasts; with monoclonal antibodies to type IV collagen – moderate positive expression in the basal membrane of blood vessels, in smooth muscle cells of the muscle layer of the vessel wall, in areas of connective tissue, which meant pathological remodeling of connective tissue. Conclusions. The similar results of histological and immunohistochemical studies in patients with signs of undifferentiated connective tissue dysplasia and intestinal sutures failure confirm the influence of connective tissue pathology on the development of this complication.

Mechanical Trapping of the Cell Nucleus Into Microgroove Concavity But Not On Convexity Induces Cell Tissue Growth and Vascular Smooth Muscle Differentiation

Mechanical Trapping of the Cell Nucleus Into Microgroove Concavity But Not On Convexity Induces Cell Tissue Growth and Vascular Smooth Muscle Differentiation

Heterozygous variants in the teashirt zinc finger homeobox 3 (TSHZ3) gene in human congenital anomalies of the kidney and urinary tract.

Around 180 genes have been associated with congenital anomalies of the kidney and urinary tract (CAKUT) in mice, and represent promising novel candidate genes for human CAKUT. In whole-exome sequencing data of two siblings with genetically unresolved multicystic dysplastic kidneys (MCDK), prioritizing variants in murine CAKUT-associated genes yielded a rare variant in the teashirt zinc finger homeobox 3 (TSHZ3) gene. Therefore, the role of TSHZ3 in human CAKUT was assessed. Twelve CAKUT patients from 9/301 (3%) families carried five different rare heterozygous TSHZ3 missense variants predicted to be deleterious. CAKUT patients with versus without TSHZ3 variants were more likely to present with hydronephrosis, hydroureter, ureteropelvic junction obstruction, MCDK, and with genital anomalies, developmental delay, overlapping with the previously described phenotypes in Tshz3-mutant mice and patients with heterozygous 19q12-q13.11 deletions encompassing the TSHZ3 locus. Comparable with Tshz3-mutant mice, the smooth muscle layer was disorganized in the renal pelvis and thinner in the proximal ureter of the nephrectomy specimen of a TSHZ3 variant carrier compared to controls. TSHZ3 was expressed in the human fetal kidney, and strongly at embryonic day 11.5-14.5 in mesenchymal compartments of the murine ureter, kidney, and bladder. TSHZ3 variants in a 5' region were more frequent in CAKUT patients than in gnomAD samples (p < 0.001). Mutant TSHZ3 harboring N-terminal variants showed significantly altered SOX9 and/or myocardin binding, possibly adversely affecting smooth muscle differentiation. Our results provide evidence that heterozygous TSHZ3 variants are associated with human CAKUT, particularly MCDK, hydronephrosis, and hydroureter, and, inconsistently, with specific extrarenal features, including genital anomalies.

Comprehensive mutational profiling identifies new driver events in cutaneous leiomyosarcoma.

Cutaneous leiomyosarcoma (cLMS) is a rare soft tissue neoplasm, showing smooth muscle differentiation, that arises from the mesenchymal cells of the dermis. To-date, genetic investigation of these tumours has involved studies with small sample sizes and limited analyses that identified recurrent somatic mutations in RB1 and TP53, copy number gain of MYCOD and IGF1R, and copy number loss of PTEN. To better understand the molecular pathogenesis of cLMS, we comprehensively explored the mutational landscape of these rare tumours to identify candidate driver events. In this retrospective, multi-institutional study, we performed whole-exome sequencing and RNA sequencing on 38 cases of cLMS. TP53 and RB1 were identified as significantly mutated, thus, represent validated driver genes of cLMS. COSMIC mutational signatures SBS7a/b and DBS1 were recurrent, thus, ultraviolet light exposure may be an aetiological factor driving cLMS. Analysis of significantly recurrent somatic copy number alterations, which represent candidate driver events, found focal (<10Mb) deletions encompassing TP53 and KDM6B, and amplifications encompassing ZMYM2, MYOCD, MAP2K4 and NCOR1. A larger (24 Mb) recurrent deletion encompassing CYLD was also identified as significant. Significantly recurrent broad copy number alterations, involving at least half of a chromosome arm, included deletions of 6p/q, 10p/q, 11q, 12q, 13q and 16p/q, and amplification of 15q. Notably PTEN is located on 10q, RB1 on 13q and IGFR1 on 15q. Fusion gene analysis identified recurrent CRTC1/3::MAML2 fusions, as well as many novel fusions in individual samples. Our analysis of the largest number of cLMS cases to-date highlights the importance of large cohort sizes and the exploration beyond small targeted gene panels when performing molecular analyses, as it allowed a comprehensive exploration of the mutational landscape of these tumours and identification of novel candidate driver events. It also uniquely afforded the opportunity to compare the molecular phenotype of cLMS with LMS of other tissue types, such as uterine and soft tissue LMS. Given that molecular profiling has resulted in the development of novel targeted treatment approaches for uterine and soft tissue LMS, our study now allows the same opportunities to become available for patients with cLMS.

Calcium wave dynamics in the embryonic mouse gut mesenchyme: impact on smooth muscle differentiation

Intestinal smooth muscle differentiation is a complex physico-biological process involving several different pathways. Here, we investigate the properties of Ca2+ waves in the developing intestinal mesenchyme using GCamp6f expressing mouse embryos and investigate their relationship with smooth muscle differentiation. We find that Ca2+ waves are absent in the pre-differentiation mesenchyme and start propagating immediately following α-SMA expression. Ca2+ waves are abrogated by CaV1.2 and gap-junction blockers, but are independent of the Rho pathway. The myosine light-chain kinase inhibitor ML-7 strongly disorganized or abolished Ca2+ waves, showing that perturbation of the contractile machinery at the myosine level also affected the upstream Ca2+ handling chain. Inhibiting Ca2+ waves and contractility with CaV1.2 blockers did not perturb circular smooth muscle differentiation at early stages. At later stages, CaV1.2 blockers abolished intestinal elongation and differentiation of the longitudinal smooth muscle, leading instead to the emergence of KIT-expressing interstitial cells of Cajal at the gut periphery. CaV1.2 blockers also drove apoptosis of already differentiated, CaV1.2-expressing smooth muscle and enteric neural cells. We provide fundamental new data on Ca2+ waves in the developing murine gut and their relation to myogenesis in this organ.

Rarely Observed Histopathological Subtypes of Endometrial Malignant Tumors in a Tertiary Care Center: A Case Series.

Introduction Endometrial cancer, one of the most prevalent gynecological malignancies, represents a significant contributor to global mortality and morbidity. The histological subtype of this cancer is pivotal in treatment planning and patient risk stratification. This case series, comprising seven cases, underscores the significance of rare endometrial cancer variants and the importance of ancillary studies, specifically immunohistochemistry, in comprehending and diagnosing the condition. Materials and methods The data of all the rare histological subtypes of malignant endometrial tumors encountered from April 2021 to April 2024 were collected. The data collected included age; risk factor; histological type; tumor, node, metastasis (TNM) stage; the International Federation of Gynecology and Obstetrics (FIGO)grade; P53; and mismatch repair (MMR) status. The histopathology specimens were reviewed using a Labomed microscope (LX500) manufactured in India. Images were taken and added wherever necessary, and the results were studied, analyzed, clinically correlated, and are shown in tables. Results Seven rare histopathological subtypes of malignant endometrial tumors were encountered in this period in this tertiary care center. This included mesonephric like adenocarcinoma, high-grade carcinosarcoma, carcinosarcoma with the serous and chondrosarcomatous components, clear cell carcinoma of endometrium, endometrial stromal sarcoma with smooth muscle differentiation, endometrial stromal sarcoma, and undifferentiated sarcoma with focal myxoid degeneration. Conclusion Diagnosis of uncommon endometrial carcinomas proves to be challenging due to their various histological subtypes, most often with overlapping features. The cornerstone of effective care lies in collaboration with clinicians, radiologists, and pathologists to identify these lesions as early as possible using a multidisciplinary approach for optimal patient outcome management.

An assessment of “neuroendocrine differentiation” in malignant melanomas of the sinonasal and oral region

Mucosal melanomas often require a detailed differential diagnosis and immunochemical study due to their different morphology and pattern characteristics. The tumors may also show fibroblastic, schwannian, smooth muscle, rhabdomyosarcomatous, gangliocytic, epithelial, and neuroendocrine differentiation. All these features can lead to serious diagnostic difficulties. The study aimed to determine the frequency of neuroendocrine differentiation in melanomas of the sinonasal and oral regions and to assess whether there is any relationship between neuroendocrine differentiation and clinical, histopathological, and other immunophenotypic features of this neoplasm. The study included 18 cases diagnosed with oral or sinonasal malignant melanoma. Neuroendocrine differentiation was determined by immunohistochemistry using synaptophysin, chromogranin, CD56, and INSM-1. A cut-off defining neuroendocrine differentiation in malignant melanomas has not been established in the literature. Because of this, any degree of neuroendocrine marker expression was considered as indicative of “neuroendocrine differentiation” without setting any cut-off. Neuroendocrine differentiation was observed in 13 of 18 cases (72.2 %) when a single positive neuroendocrine marker was considered sufficient. The number of cases with at least two positive neuroendocrine markers was 8/18 (44.4 %). Synaptophysin, chromogranin A, CD56, and INSM1 were positive in 33.3 %, 13.3 %, 56.2 %, and 47.1 % of cases, respectively. The results of our study suggest that neuroendocrine differentiation is not uncommon in oral and sinonasal melanomas. Knowing that malignant melanomas can show neuroendocrine differentiation will prevent diagnostic pitfalls.

Low-grade endometrial stromal sarcoma with extensive sex cord and smooth muscle differentiation: report of a case

Low-grade endometrial stromal sarcoma with extensive sex cord and smooth muscle differentiation: report of a case

From Fat to Muscle: Smooth Muscle Differentiation of Adipose-derived Stem Cells Using a Combination of Biomechanical and Biochemical Induction

From Fat to Muscle: Smooth Muscle Differentiation of Adipose-derived Stem Cells Using a Combination of Biomechanical and Biochemical Induction

CPLANE protein INTU regulates growth and patterning of the mouse lungs through cilia-dependent Hh signaling

Congenital lung malformations are fatal at birth in their severe forms. Prevention and early intervention of these birth defects require a comprehensive understanding of the molecular mechanisms of lung development. We find that the loss of inturned (Intu), a cilia and planar polarity effector gene, severely disrupts growth and branching morphogenesis of the mouse embryonic lungs. Consistent with our previous results indicating an important role for Intu in ciliogenesis and hedgehog (Hh) signaling, we find greatly reduced number of primary cilia in both the epithelial and mesenchymal tissues of the lungs. We also find significantly reduced expression of Gli1 and Ptch1, direct targets of Hh signaling, suggesting disruption of cilia-dependent Hh signaling in Intu mutant lungs. An agonist of the Hh pathway activator, smoothened, increases Hh target gene expression and tubulogenesis in explanted wild type, but not Intu mutant, lungs, suggesting impaired Hh signaling response underlying lung morphogenetic defects in Intu mutants. Furthermore, removing both Gli2 and Intu completely abolishes branching morphogenesis of the lung, strongly supporting a mechanism by which Intu regulates lung growth and patterning through cilia-dependent Hh signaling. Moreover, a transcriptomics analysis identifies around 200 differentially expressed genes (DEGs) in Intu mutant lungs, including known Hh target genes Gli1, Ptch1/2 and Hhip. Genes involved in muscle differentiation and function are highly enriched among the DEGs, consistent with an important role of Hh signaling in airway smooth muscle differentiation. In addition, we find that the difference in gene expression between the left and right lungs diminishes in Intu mutants, suggesting an important role of Intu in asymmetrical growth and patterning of the mouse lungs.

Role of Fine Needle Aspiration Cytology in Diagnosing Paratesticular Leiomyoma

Leiomyomas are benign neoplasms with smooth muscle differentiation. Paratesticular leiomyomas are extremely uncommon. Fine Needle Aspiration Cytology (FNAC) serves as a rapid, safe and conclusive diagnostic tool which prevents unnecessary surgical interventions. We report a rare case of paratesticular leiomyoma, in an asymptomatic 40-year old male diagnosed on cytomorphology. This was further confirmed on histopathological examination (HPE) and immunohistochemistry (IHC). This case emphasizes the role of FNAC in providing a definitive diagnosis.

Novel CRTC1::MRTFB(MKL2) Gene Fusion Detected in Myxoid Mesenchymal Neoplasms With Myogenic Differentiation Involving Bone and Soft Tissues

Appropriate classification of fusion-driven bone and soft tissue neoplasms continues to evolve, often relying on the careful integration of morphologic findings with immunohistochemical, molecular, and clinical data. Herein, we present 3 cases of a morphologically distinct myxoid mesenchymal neoplasm with myogenic differentiation and novel CRTC1::MRTFB (formerly MKL2) gene fusion. Three tumors occurred in 1 male and 2 female patients with a median age of 72 years (range: 28-78). Tumors involved the left iliac bone, the right thigh, and the left perianal region with a median size of 4.0 cm (4.0-7.6 cm). Although 1 tumor presented as an incidental finding, the other 2 tumors were noted, given their persistent growth. At the time of the last follow-up, 1 patient was alive with unresected disease at 6 months, 1 patient was alive without evidence of disease at 12 months after surgery, and 1 patient died of disease 24 months after diagnosis. On histologic sections, the tumors showed multinodular growth and were composed of variably cellular spindle to round-shaped cells with distinct brightly eosinophilic cytoplasm embedded within a myxoid stroma. One tumor showed overt smooth muscle differentiation. Cytologic atypia and mitotic activity ranged from minimal (2 cases) to high (1 case). By immunohistochemistry, the neoplastic cells expressed focal smooth muscle actin, h-caldesmon, and desmin in all tested cases. Skeletal muscle markers were negative. Next-generation sequencing detected nearly identical CRTC1::MRTFB gene fusions in all cases. We suggest that myxoid mesenchymal tumors with myogenic differentiation harboring a CRTC1::MRTFB fusion may represent a previously unrecognized, distinctive entity that involves soft tissue and bone. Continued identification of these novel myxoid neoplasms with myogenic differentiation will be important in determining appropriate classification, understanding biologic potential, and creating treatment paradigms.

A novel mouse model carrying a gene trap insertion into the Hmgxb4 gene locus to examine Hmgxb4 expression invivo.

HMG (high mobility group) proteins are a diverse family of nonhistone chromosomal proteins that interact with DNA and a wide range of transcriptional regulators to regulate the structural architecture of DNA. HMGXB4 (also known as HMG2L1) is an HMG protein family member that contains a single HMG box domain. Our previous studies have demonstrated that HMGXB4 suppresses smooth muscle differentiation and exacerbates endotoxemia by promoting a systemic inflammatory response in mice. However, the expression of Hmgxb4 invivo has not fully examined. Herein, we generated a mouse model that harbors a gene trap in the form of a lacZ gene insertion into the Hmgxb4 gene. This mouse enables the visualization of endogenous HMGXB4 expression in different tissues via staining for the β-galactosidase activity of LacZ which is under the control of the endogenous Hmgxb4 gene promoter. We found that HMGXB4 is widely expressed in mouse tissues and is a nuclear protein. Furthermore, the Hmgxb4 gene trap mice exhibit normal cardiac function and blood pressure. Measurement of β-galactosidase activity in the Hmgxb4 gene trap mice demonstrated that the arterial injury significantly induces Hmgxb4 expression. In summary, the Hmgxb4 gene trap reporter mouse described here provides a valuable tool to examine the expression level of endogenous Hmgxb4 in both physiological and pathological settings invivo.

Abstract 5135: Tertiary lymphoid structures and T-cell aggregates signal a robust anti-tumor immune response in a subset of leiomyosarcoma patients

Abstract Cancer immunotherapy has ushered in a new era for treatment of many difficult to treat cancers such as Leiomyosarcoma (LMS), one of the most common subtypes of sarcomas. There are few biomarkers which can be used to identify patients who might benefit from immunotherapy. There is an urgent need to discover novel biomarkers which might be prognostic of a strong anti-tumor response. We thus sought to comprehensively profile the microenvironment of LMS tumors to identify features which might be suggestive of an active immune response and molecular features prognostic of response to immunotherapy. We began our analysis by classifying the LMS tumors from The Cancer Genome Atlas (TCGA) into 4 subtypes based on previously identified molecular features and comparing the enrichment of various immune gene signatures. Two of the subtypes had a high expression of various immune gene signatures including B Cells, M2 macrophages and Cytotoxic T cells. Visual inspection of the Hematoxylin and Eosin-stained tissue slides available with TCGA pointed to a presence of lymphoid aggregates or Tertiary lymphoid structures (TLS) in 10-15% of the tumors - predominantly belonging to one of the two subtypes. This subtype displayed features of smooth muscle differentiation and was also associated with improved survival. To validate our findings, we performed immunohistochemistry (IHC) and bulk RNA sequencing of LMS specimens (n=66) obtained from surgical resections from the Johns Hopkins Hospital. We identified mature CD21+ TLS in 15% of these cases and non-germinal center T cell aggregates present in more than 30% of the cases and these features were associated with improved survival. We digitally merged the different IHC sections to study if the markers were spatially correlated. Interestingly, spatial analysis showed that these CD8 T cells aggregates co-localized with neighborhoods of high density of PD-L1+ cells, hinting at the possibility of immune mediated upregulation of PD-L1 as means of immune suppression. The deconvolution of the transcriptome of these samples showed a marked presence of cytotoxic CD8 T cells and plasma B cells in this subset of patients, an enrichment of pathways related to T cell trafficking, activation and proliferation. Single cell RNA sequencing of tumor infiltrating immune cells showed an oligoclonal expansion of B and T cells. Taken together, this study shows that a subset of LMS patients have a strong anti-tumor immune response which is characterized by the presence of Tertiary Lymphoid Structures and patches of high density of PD-L1 expressing cells. These features might serve as biomarkers in screening LMS patients which might benefit from immunotherapy. Citation Format: Aditya Suru, Alexandre Maalouf, Lingling Chen, Ada Tam, William Villasi, Kaushal Sharma, Lindy Zhang, Christian Meyer, Jonathan Greer, Fabian Johnston, Carol Morris, Sophia Strike, Adam Levin, Daniel Rhee, Brian Ladle, Kornel Schuebel, Yan Zhang, Rulin Wang, Srinivasan Yegnasubramanian, John Gross, Robert Anders, Andrew Pardoll, Nicolas Llosa. Tertiary lymphoid structures and T-cell aggregates signal a robust anti-tumor immune response in a subset of leiomyosarcoma patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5135.

Mechanical memory based on chromatin and metabolism remodeling promotes proliferation and smooth muscle differentiation in mesenchymal stem cells.

Stem cells respond and remember mechanical cues from the microenvironment, which modulates their therapeutic effects. Chromatin organization and energy metabolism regulate the stem cell fate induced by mechanical cues. However, the mechanism of mechanical memory is still unclear. This study aimed to investigate the effects of mechanical amplitude, frequency, duration, and stretch cycle on mechanical memory in mesenchymal stem cells. It showed that the amplitude was the dominant parameter to the persistence of cell alignment. F-actin, paxillin, and nuclear deformation are more prone to be remolded than cell alignment. Stretching induces transcriptional memory, resulting in greater transcription upon subsequent reloading. Cell metabolism displays mechanical memory with sustained mitochondrial fusion and increased ATP production. The mechanical memory of chromatin condensation is mediated by histone H3 lysine 27 trimethylation, leading to much higher smooth muscle differentiation efficiency. Interestingly, mechanical memory can be transmitted based on direct cell-cell interaction, and stretched cells can remodel the metabolic homeostasis of static cells. Our results provide insight into the underlying mechanism of mechanical memory and its potential benefits for stem cell therapy.

RETROPERITONEAL LEIOMYOMA OF GYNECOLOGIC TYPE: A CASE REPORT AND REVIEW OF THE LITERATURE

Retroperitoneal leiomyomas are rare benign tumors with smooth muscle differentiation, because of its scarcity and non-specific presentation, the preoperative diagnosis might be challenging. This current paper we reported a case of 60years old, who was seen in OPD with abdominal pain. Ultrasound demonstrated a mass which was initially thought to be related to the ovary. CT scan was done which showed possible uterine mass. Patient undergone laparoscopy, the tumor was clearly retroperitoneal fibroid. Report of histopathology report demonstrated Leiomyoma.

Myocardin regulates fibronectin expression and secretion from human pleural mesothelial cells.

During the progression of pleural fibrosis, pleural mesothelial cells (PMCs) undergo a phenotype switching process known as mesothelial-mesenchymal transition (MesoMT). During MesoMT, transformed PMCs become myofibroblasts that produce increased extracellular matrix (ECM) proteins, including collagen and fibronectin (FN1) that is critical to develop fibrosis. Here, we studied the mechanism that regulates FN1 expression in myofibroblasts derived from human pleural mesothelial cells (HPMCs). We found that myocardin (Myocd), a transcriptional coactivator of serum response factor (SRF) and a master regulator of smooth muscle and cardiac muscle differentiation, strongly controls FN1 gene expression. Myocd gene silencing markedly inhibited FN1 expression. FN1 promoter analysis revealed that deletion of the Smad3-binding element diminished FN1 promoter activity, whereas deletion of the putative SRF-binding element increased FN1 promoter activity. Smad3 gene silencing decreased FN1 expression, whereas SRF gene silencing increased FN1 expression. Moreover, SRF competes with Smad3 for binding to Myocd. These results indicate that Myocd activates FN1 expression through Smad3, whereas SRF inhibits FN1 expression in HPMCs. In HPMCs, TGF-β induced Smad3 nuclear localization, and the proximity ligation signal between Myocd and Smad3 was markedly increased after TGF-β stimulation at nucleus, suggesting that TGF-β facilitates nuclear translocation of Smad3 and interaction between Smad3 and Myocd. Moreover, Myocd and Smad3 were coimmunoprecipitated and isolated Myocd and Smad3 proteins directly bound each other. Chromatin immunoprecipitation assays revealed that Myocd interacts with the FN1 promoter at the Smad3-binding consensus sequence. The results indicate that Myocd regulates FN1 gene activation through interaction and activation of the Smad3 transcription factor.NEW & NOTEWORTHY During phenotype switching from mesothelial to mesenchymal, pleural mesothelial cells (PMCs) produce extracellular matrix (ECM) proteins, including collagen and fibronectin (FN1), critical components in the development of fibrosis. Here, we found that myocardin, a transcriptional coactivator of serum response factor (SRF), strongly activates FN1 expression through Smad3, whereas SRF inhibits FN1 expression. This study provides insights about the regulation of FN1 that could lead to the development of novel interventional approaches to prevent pleural fibrosis.

Dedifferentiated Leiomyosarcoma of the Uterine Corpus with Heterologous Component: Clinicopathological Analysis of Five Consecutive Cases from a Single Institution and Comprehensive Literature Review.

Dedifferentiation is a very rare phenomenon in uterine leiomyosarcoma (LMS). The aim of this study was to comprehensively analyze the clinicopathological characteristics of uterine dedifferentiated LMS (DDLMS). We reviewed electronic medical records and pathology slides from five patients with uterine DDLMS and performed immunostaining. The mean age of the patients was 56 years. Two patients presented with abdominal discomfort, while in three cases the uterine tumors were detected on routine medical examination. The mean size of the tumors was 17.0 cm. Four patients underwent hysterectomy. The initial stages were distributed as IB (2/5), IIIC (2/5), and IVC (1/5). Post-operative concurrent chemoradiation therapy, radiation therapy, and chemotherapy were administered in one, one, and two patients, respectively. Despite post-operative treatment, three patients developed metastatic recurrences in the abdominal and pelvic organs. Recurrence-free survival time ranged between 4 and 30 months. Histologically, the differentiated areas demonstrated the classic morphology of malignant smooth muscle differentiation, whereas the dedifferentiated areas resembled undifferentiated pleomorphic sarcoma and were characterized by large pleomorphic tumor cells admixed with haphazardly arranged atypical cells with marked nuclear pleomorphism. All cases also exhibited heterologous components, including chondrosarcoma (CSA; 3/5) and rhabdomyosarcoma (2/5). In two cases, the heterologous components were initially detected in primary tumors. In three cases, the primary tumors did not exhibit any dedifferentiated or heterologous components. Instead, more than half of the recurrent tumors consisted of heterologous components. Three cases showed a sharp demarcation between the LMS and CSA components, while in two cases the dedifferentiated area imperceptibly merged with the differentiated component. Immunostaining revealed that the dedifferentiated components exhibited a lack of desmin immunoreactivity in three of the four examined cases. A subset of uterine LMS represents various amounts and types of dedifferentiation and heterologous components in both primary and recurrent tumors. Routine recognition of DDLMS and distinction from its mimickers are required for accurate diagnosis and further characterization of these rare tumors.

Molecular Mechanism of Calycosin Inhibited Vascular Calcification.

Vascular calcification (VC) is a pathological condition frequently observed in cardiovascular diseases. Primary factors contributing to VC are osteogenic differentiation of vascular smooth muscle and hydroxyapatite deposition. Targeted autophagy (a lysosome-mediated mechanism for degradation/recycling of unnecessary cellular components) is a useful approach for inhibiting VC and promoting vascular cell health. Calycosin has been shown to alleviate atherosclerosis by enhancing macrophage autophagy, but its therapeutic effect on VC has not been demonstrated. Using an in vitro model (rat thoracic aortic smooth muscle cell line A7r5), we demonstrated effective inhibition of VC using calycosin (the primary flavonoid component of astragalus), based on the enhancement of autophagic flux. Calycosin treatment activated AMPK/mTOR signaling to induce initiation of autophagy and restored mTORC1-dependent autophagosome-lysosome fusion in late-stage autophagy by promoting soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex formation, thereby preventing stoppage of autophagy in calcified cells. Calycosin substantially reduced degrees of both osteogenic differentiation and calcium deposition in our VC cell model by enhancing autophagy. The present findings clarify the mechanism whereby calycosin mitigates autophagy stoppage in calcified smooth muscle cells and provide a basis for effective VC treatment via autophagy enhancement.

PDE4 Phosphodiesterases in Cardiovascular Diseases: Key Pathophysiological Players and Potential Therapeutic Targets

3′,5′-cyclic adenosine monophosphate (cAMP) is a second messenger critically involved in the control of a myriad of processes with significant implications for vascular and cardiac cell function. The temporal and spatial compartmentalization of cAMP is governed by the activity of phosphodiesterases (PDEs), a superfamily of enzymes responsible for the hydrolysis of cyclic nucleotides. Through the fine-tuning of cAMP signaling, PDE4 enzymes could play an important role in cardiac hypertrophy and arrhythmogenesis, while it decisively influences vascular homeostasis through the control of vascular smooth muscle cell proliferation, migration, differentiation and contraction, as well as regulating endothelial permeability, angiogenesis, monocyte/macrophage activation and cardiomyocyte function. This review summarizes the current knowledge and recent advances in understanding the contribution of the PDE4 subfamily to cardiovascular function and underscores the intricate challenges associated with targeting PDE4 enzymes as a therapeutic strategy for the management of cardiovascular diseases.