Developmentally regulated expression of calponin isoforms and the effect of h2-calponin on cell proliferation

Histone deacetylase inhibition enhances extracellular vesicles from muscle to promote osteogenesis via miR-873-3p

Regular physical activity is widely recognized for reducing the risk of various disorders, with skeletal muscles playing a key role by releasing biomolecules that benefit multiple organs and tissues. However, many individuals, particularly the elderly and those with clinical conditions, are unable to engage in physical exercise, necessitating alternative strategies to stimulate muscle cells to secrete beneficial biomolecules. Histone acetylation and deacetylation significantly influence exercise-induced gene expression, suggesting that targeting histone deacetylases (HDACs) could mimic some exercise responses. In this study, we explored the effects of the HDAC inhibitor Trichostatin A (TSA) on human skeletal muscle myoblasts (HSMMs). Our findings showed that TSA-induced hyperacetylation enhanced myotube fusion and increased the secretion of extracellular vesicles (EVs) enriched with miR-873-3p. These TSA-EVs promoted osteogenic differentiation in human bone marrow mesenchymal stem cells (hBMSCs) by targeting H2 calponin (CNN2). In vivo, systemic administration of TSA-EVs to osteoporosis mice resulted in significant improvements in bone mass. Moreover, TSA-EVs mimicked the osteogenic benefits of exercise-induced EVs, suggesting that HDAC inhibition can replicate exercise-induced bone health benefits. These results demonstrate the potential of TSA-induced muscle-derived EVs as a therapeutic strategy to enhance bone formation and prevent osteoporosis, particularly for individuals unable to exercise. Given the FDA-approved status of various HDAC inhibitors, this approach holds significant promise for rapid clinical translation in osteoporosis treatment.

Mechanoregulation and function of calponin and transgelin

It is well known that chemical energy can be converted to mechanical force in biological systems by motor proteins such as myosin ATPase. It is also broadly observed that constant/static mechanical signals potently induce cellular responses. However, the mechanisms that cells sense and convert the mechanical force into biochemical signals are not well understood. Calponin and transgelin are a family of homologous proteins that participate in the regulation of actin-activated myosin motor activity. An isoform of calponin, calponin 2, has been shown to regulate cytoskeleton-based cell motility functions under mechanical signaling. The expression of the calponin 2 gene and the turnover of calponin 2 protein are both under mechanoregulation. The regulation and function of calponin 2 has physiological and pathological significance, as shown in platelet adhesion, inflammatory arthritis, arterial atherosclerosis, calcific aortic valve disease, post-surgical fibrotic peritoneal adhesion, chronic proteinuria, ovarian insufficiency, and tumor metastasis. The levels of calponin 2 vary in different cell types, reflecting adaptations to specific tissue environments and functional states. The present review focuses on the mechanoregulation of calponin and transgelin family proteins to explore how cells sense steady tension and convert the force signal to biochemical activities. Our objective is to present a current knowledge basis for further investigations to establish the function and mechanisms of calponin and transgelin in cellular mechanoregulation.

Loss of Calponin 2 causes premature ovarian insufficiency in mice

BACKGROUND

Premature ovarian insufficiency (POI) is a condition defined as women developing menopause before 40 years old. These patients display low ovarian reserve at young age and difficulties to conceive even with assisted reproductive technology. The pathogenesis of ovarian insufficiency is not fully understood. Genetic factors may underlie most of the cases. Actin cytoskeleton plays a pivotal role in ovarian folliculogenesis. Calponin 2 encoded by the Cnn2 gene is an actin associated protein that regulates motility and mechanical signaling related cellular functions.

RESULTS

The present study compared breeding of age-matched calponin 2 knockout (Cnn2-KO) and wild type (WT) mice and found that Cnn2-KO mothers had significantly smaller litter sizes. Ovaries from 4 weeks old Cnn2-KO mice showed significantly lower numbers of total ovarian follicles than WT control with the presence of multi-oocyte follicles. Cnn2-KO mice also showed age-progressive earlier depletion of ovarian follicles. Cnn2 expression is detected in the cumulus cells of the ovarian follicles of WT mice and colocalizes with actin stress fiber, tropomyosin and myosin II in primary cultures of cumulus cells.

CONCLUSIONS

The findings demonstrate that the loss of calponin 2 impairs ovarian folliculogenesis with premature depletion of ovarian follicles. The role of calponin 2 in ovarian granulosa cells suggests a molecular target for further investigations on the pathogenesis of POI and for therapeutic development.

CNN2 silencing inhibits colorectal cancer development through promoting ubiquitination of EGR1

Colorectal cancer (CRC) is one of the most commonly diagnosed malignant tumors of the digestive tract. H2-calponin (CNN2), an actin cytoskeleton-binding protein, is an isoform of the calponin protein family whose role in CRC is still unknown. Research based on clinical samples showed the up-regulation of CNN2 in CRC and its association with tumor development, metastasis, and poor prognosis of patients. Both in vitro loss-of-function and gain-of-function experiments showed that CNN2 participates in CRC development through influencing malignant cell phenotypes. In vivo, xenografts formed by CNN2 knockdown cells also showed a slower growth rate and smaller final tumors. Furthermore, EGR1 was identified as a downstream of CNN2, forming a complex with CNN2 and YAP1 and playing an essential role in the CNN2-induced regulation of CRC development. Mechanistically, CNN2 knockdown down-regulated EGR1 expression through enhancing its ubiquitination, thus decreasing its protein stability in a YAP1-dependent manner. In summary, CNN2 plays an EGR1-dependent promotion role in the development and progression of CRC, which may be a promising therapeutic target for CRC treatment.

Evolution and function of calponin and transgelin

Calponin and transgelin (originally named SM22) are homologous cytoskeleton proteins that regulate actin-activated myosin motor functions in smooth muscle contraction and non-muscle cell motility during adhesion, migration, proliferation, phagocytosis, wound healing, and inflammatory responses. They are abundant cytoskeleton proteins present in multiple cell types whereas their physiological functions remain to be fully established. This focused review summarizes the evolution of genes encoding calponin and transgelin and their isoforms and discusses the structural similarity and divergence in vertebrate and invertebrate species in the context of functions in regulating cell motility. As the first literature review focusing on the evolution of the calponin-transgelin family of proteins in relevance to their structure-function relationship, the goal is to outline a foundation of current knowledge for continued investigations to understand the biological functions of calponin and transgelin in various cell types during physiological and pathological processes.

The Role of H2-Calponin Antigen in Cancer Metastasis: Presence of Autoantibodies in Liver Cancer Patients

To investigate the potential of H2-calponin (CNN2) as a serum biomarker for hepatocellular carcinoma (HCC), this study employed the serological analysis of recombinantly expressed cDNA clone (SEREX) technique to identify the presence of CNN2 antibody in the serum of patients with HCC and other tumors. The CNN2 protein was produced through genetic engineering and used as an antigen to determine the positive rate of serum CNN2 autoantibodies via indirect enzyme-linked immunosorbent assay (ELISA). In addition, the mRNA and protein expressions of CNN2 in cells and tissues were evaluated using RT-PCR, in situ RT-PCR, and immunohistochemistry methods. The HCC group exhibited a significantly higher positive rate of anti-CNN2 antibody (54.8%) compared to gastric cancer (6.5%), lung cancer (3.2%), rectal cancer (9.7%), hepatitis (3.2%), liver cirrhosis (3.2%), and normal tissues (3.1%). The positive rates of CNN2 mRNA in HCC with metastasis, non-metastatic HCC, lung cancer, gastric cancer, nasopharyngeal cancer, liver cirrhosis, and hepatitis were 56.67%, 41.67%, 17.5%, 10.0%, 20.0%, 53.13%, and 41.67%, respectively. Meanwhile, the positive rates of CNN2 protein were 63.33%, 37.5%, 17.5%, 27.5%, 45%, 31.25%, and 20.83%, respectively. The down-regulation of CNN2 could inhibit the migration and invasion of liver cancer cells. CNN2 is a newly identified HCC-associated antigen that is implicated in the migration and invasion of liver cancer cells, making it a promising target for liver cancer therapy.

Loss of Calponin 2 causes age-progressive proteinuria in mice

Proteinuria is a major manifestation of kidney disease, reflecting injuries of glomerular podocytes. Actin cytoskeleton plays a pivotal role in stabilizing the foot processes of podocytes against the hydrostatic pressure of filtration. Calponin is an actin associated protein that regulates mechanical tension-related cytoskeleton functions and its role in podocytes has not been established. Here we studied the kidney phenotypes of calponin isoform 2 knockout (KO) mice. Urine samples were examined to quantify the ratio of albumin and creatinine. Kidney tissue samples were collected for histology and ultrastructural studies. A mouse podocyte cell line (E11) was used to study the expression and cellular localization of calponin 2. In comparison with wild-type (WT) controls, calponin 2 KO mice showed age-progressive high proteinuria and degeneration of renal glomeruli. High levels of calponin 2 are expressed in E11 podocytes and colocalized with actin stress fibers, tropomyosin and myosin IIA. Electron microscopy showed that aging calponin 2 KO mice had effacement of the podocyte foot processes and increased thickness of the glomerular basement membrane as compared to that of WT control. The findings demonstrate that deletion of calponin 2 aggravates age-progressive degeneration of the glomerular structure and function as filtration barrier. The critical role of calponin 2 in podocytes suggests a molecular target for understanding the pathogenesis of proteinuria and therapeutic development.

A Preparative Method for the Isolation of Calponin from Molluscan Catch Muscle

We describe the development of a preparative method to isolate molluscan catch muscle, calponin. This method is based on the ability of calponin to interact with actin in a temperature-dependent manner. After extracting thin filaments, as previously described, the extract was ultracentrifuged at 2 °C. While other surface proteins of thin filaments co-precipitated with actin, calponin, along with some minor contaminants, remained in the supernatant. Calponin was purified through cation-exchange chromatography. The yield of pure protein was four-fold higher than that achieved through high-temperature extraction. To evaluate functionally isolated proteins, we determined the effect of calponin on Mg²⁺-ATPase activity of hybrid and non-hybrid actomyosin. The degree of ATPase inhibition was consistent with previously published data but strongly dependent on the environmental conditions and source of actin and myosin used. Furthermore, at low concentrations, calponin could induce the ATPase activity of hybrid actomyosin. This result was consistent with data indicating that calponin can modulate actin conformation to increase the relative content of “switched on” actin monomers in thin filaments. We assume that calponin obtained by the isolation method proposed herein is a fully functional protein that can both inhibit and induce the ATPase activity.

Deletion of Calponin 2 Reduces the Formation of Postoperative Peritoneal Adhesions

Aim of the study: Postoperative peritoneal adhesions are a common cause of morbidity after surgery, resulting in multiple complications. Macrophage-mediated inflammation and myofibroblast differentiation after tissue injury play central roles in the pathogenesis and progression of adhesion formation. Calponin 2 is an actin cytoskeleton regulatory protein in endothelial cells, macrophages and fibroblasts that are key players in the development of fibrosis. Deletion of calponin 2 has been shown to attenuate inflammatory arthritis, atherosclerosis and fibrocalcification of the aortic valves. The present study investigated the effect of calponin 2 deletion on attenuating the formation of peritoneal adhesions in a mouse model for potential use as a new therapeutic target.Materials and methods: Sterile surgical procedures under general anesthesia were used on paired wild type (WT) and calponin 2 knockout (KO) mice to generate mild injury on the cecal and abdominal wall peritonea. Three and seven days post-operation, the mice were compared postmortem for the formation of peritoneal adhesions. Tissues at the adhesion sites were examined with histology and immunofluorescent studies for macrophage and myofibroblast activations.Results: Quantitative scoring demonstrated that calponin 2 KO mice developed significantly less postoperative peritoneal adhesions than that in WT mice. Calponin 2 deletion resulted in less infiltration of F4/80⁺ macrophages at the adhesion sites with less myofibroblast differentiation and collagen deposition than WT controls.Conclusions: The data show that deletion of calponin 2 effectively reduces postoperative peritoneal adhesion, presenting a novel molecular target for clinical prevention.

A rapid degradation of calponin 2 is required for cytokinesis

Calponin 2 is an actin cytoskeleton-associated protein and plays a role in regulating cell motility-related functions such as phagocytosis, migration, and division. We previously reported that overexpression of calponin 2 inhibits the rate of cell proliferation. To investigate the underlying mechanism, our present study found that the levels of endogenous calponin 2 in NIH3T3 and HEK293 cells rapidly decreased before cell division characterized by an absence at the actin contractile ring. In cells lacking endogenous calponin 2, transfective expression of GFP-fusion calponin 2 inhibited cell proliferation similar to that of nonfusion calponin 2. Fluorescent imaging studies of mitotic cells indicated that a proper level of calponin 2 expression and effective degradation during cytokinesis are necessary for normal cell division. Computer-assisted dynamic image analysis of dividing cells revealed that overexpression of calponin 2 significantly affects motility and shape behaviors of cells only on the interval from the start of anaphase to the start of cytokinesis, i.e., the pre-cytokinesis phase, but not on the interval from the start of cytokinesis to 50% completion of cytokinesis. The pre-cytokinesis degradation of calponin 2 was attenuated by MG132 inhibition of the ubiquitin proteasome and inhibitor of protein kinase C (PKC), suggesting that PKC phosphorylation-triggered degradation of calponin 2 could determine the rate of cytokinesis. The novel role of calponin 2 in regulating the rate of cytokinesis may be targeted for therapeutic applications such as in an inhibition of malignant tumor growth.

Age-Related Alterations in the Testicular Proteome of a Non-Human Primate

Aging of human testis and associated cellular changes is difficult to assess. Therefore, we used a translational, non-human primate model to get insights into underlying cellular and biochemical processes. Using proteomics and immunohistochemistry, we analyzed testicular tissue of young (age 2 to 3) and old (age 10 to 12) common marmosets (Callithrix jacchus). Using a mass spectrometry-based proteomics approach, we identified 63,124 peptides, which could be assigned to 5924 proteins. Among them, we found proteins specific for germ cells and somatic cells, such as Leydig and Sertoli cells. Quantitative analysis showed 31 differentially abundant proteins, of which 29 proteins were more abundant in older animals. An increased abundance of anti-proliferative proteins, among them CDKN2A, indicate reduced cell proliferation in old testes. Additionally, an increased abundance of several small leucine rich repeat proteoglycans and other extracellular matrix proteins was observed, which may be related to impaired cell migration and fibrotic events. Furthermore, an increased abundance of proteins with inhibitory roles in smooth muscle cell contraction like CNN1 indicates functional alterations in testicular peritubular cells and may mirror a reduced capacity of these cells to contract in old testes.

Infiltration of inflammatory factors induced penile damage in chronic prostatitis

The present study aimed to investigate the mechanism of penile damages in experimental autoimmune prostatitis (EAP) rat models to reveal the potential pathological mechanism of the relationship between CP and penile damages. Sprague-Dawley (SD) rats were administered with different concentrations of prostate tissue homogenate supernatant (PTHS) by multipoint subcutaneous injection to establish EAP models. IHC staining was done to assess the expression of inflammatory cytokines in prostate tissues and the corpus cavernosum of penis. Masson and Tunel staining was conducted to observe the fibrosis and apoptosis in the corpus cavernosum. Finally, the functional changes of corpus cavernosum were assessed by WB and IHC staining. The results revealed that EAP rats with different prostatitis severity were successfully established by PTHS. The expression of IL-1β, IL-6 and TNF-α in prostate tissues increased with the concentration of PTHS. The results of Masson and Tunel staining indicated fibrosis and apoptosis gradually aggravated in corpus cavernosum among different subgroups. The function of cavernosum impaired by prostatitis from WB and IHC results and positively with the severity. In conclusion, there existed the infiltration of inflammatory factors and impaired function in the corpus cavernosum of EAP rats' penis and positively correlated with the severity of prostatitis.

Diversification of the calponin family proteins by gene amplification and repeat expansion of calponin-like motifs

The calponin family proteins in vertebrates, including calponin and transgelin (also known as SM22 or NP25), regulate actin-myosin interaction and actin filament stability and are involved in regulation of muscle contractility and cell migration. Related proteins are also present in invertebrates and fungi. Animals have multiple genes encoding calponin family proteins with variable molecular features, which are often expressed in the same tissues or cells. However, functional studies of this class of proteins have been reported only in limited species. Through database searches, I found that the calponin family proteins were diversified in animals by gene amplification and repeat expansion of calponin-like (CLIK) motifs, which function as actin-binding sequences. Transgelin-like proteins with a single CLIK motif are the most primitive type and present in fungi and animals. In many animals, additional calponin family proteins containing multiple CLIK motifs, as represented by vertebrate calponins with three CLIK motifs, are present. Interestingly, in several invertebrate species, there are uncharacterized calponin-related proteins with highly expanded repeats of CLIK motifs (up to 23 repeats in mollusks). These variable molecular features of the calponin family proteins may be results of evolutionary adaptation to a broad range of cell biological events.

The effect of TGFβRI inhibition on fibroblast heterogeneity in hypertrophic scar 2D in vitro models

In burn patients, wound healing is often accompanied by hypertrophic scarring (HTS), resulting in both functional and aesthetic problems. HTSs are characterized by abundant presence of myofibroblasts (MFs) residing in the dermis. HTS development and MF persistence is primarily regulated by TGF-β signalling. A promising method to target the transforming growth factor receptor I (TGFβRI; also known as activin-like kinase 5 (ALK5)) is by making use of exon skipping through antisense oligonucleotides. In HTS the distinguishing border between the papillary dermis and the reticular dermis is completely abrogated, thus exhibiting a one layered dermis containing a heterogenous fibroblast population, consisting of papillary fibroblasts (PFs), reticular fibroblasts (RFs) and MFs. It has been proposed that PFs, as opposed to RFs, exhibit anti-fibrotic properties. Currently, it is still unclear which fibroblast subtype is most affected by exon skipping treatment. Therefore, the aim of this study was to investigate the effect of TGFβRI inhibition by exon skipping in PF, RF and HTS fibroblast monocultures. Morphological analyses revealed the presence of a PF-like population after exon skipping in the different fibroblast cultures. This observation was further confirmed by the expression of genes specific for PFs, demonstrated by qPCR analyses. Further investigations on mRNA and protein level revealed that indeed MFs and to a lesser extent RFs are targeted by exon skipping. Furthermore, collagen gel contraction analysis showed that ALK5 exon skipping reduced TGF-β- induced contraction together with decreased alpha-smooth muscle actin expression levels. In conclusion, we show for the first time that exon skipping primarily targets pro-fibrotic fibroblasts. This could be a promising step towards reduced HTS development of burn tissue.

miR-106b-5p contributes to the lung metastasis of breast cancer via targeting CNN1 and regulating Rho/ROCK1 pathway

OBJECTIVES

Breast cancer has been the second most prevalent and fatal malignancy due to its frequent metastasis to other organs. We aim to study the effects of a key miRNA-mRNA signaling in breast cancer.

RESULTS

CNN1 was identified as the key gene in breast cancer by the bioinformatics analysis, and the downregulation of CNN1 in breast cancer tissues and cell lines was observed. Upregulating CNN1 inhibited cell survival, migration, invasion, and adhesion, but enhanced cell apoptosis. miR-106b-5p not only bound to CNN1 mRNA 3'UTR, but also promoted lung metastasis in vivo. Besides, the miR-106b-5p mimic enhanced breast cancer canceration by targeting CNN1 and activating Rho/ROCK1 signaling pathway.

CONCLUSION

Overall, our results proved that miR-106b-5p promoted the metastasis of breast cancer by suppressing CNN1 and activating Rho/ROCK1 pathway.

METHODS

Bioinformatics analysis was performed to select the key gene in breast cancer. The overexpression and knockdown of Calponin 1 (CNN1) in breast cancer cell lines were performed to conduct cell viability, migrating, invasion, proliferation, adhesion, and apoptosis experiments. To identify the role of miR-106b-5p and Rho/ROCK1 in CNN1-induced breast cancer, a dual-luciferase assay, tumor lung metastasis assay, transcript half-life assay, and Rho/ROCK1 inhibition assay were performed.

LncRNA NEAT1 Promotes Proliferation, Migration And Invasion Via Regulating miR-296-5p/CNN2 Axis In Hepatocellular Carcinoma Cells

Background

Emerging evidence has revealed that long noncoding RNA nuclear paraspeckle assembly transcript 1 (lncRNA NEAT1) is implicated in the development of various cancers. However, the underlying molecular mechanisms of NEAT1 in hepatocellular carcinoma (HCC) remain unclear.

Methods

The expression of NEAT1, miR-296-5p and Calponin 2 (CNN2) was detected by quantitative real-time polymerase chain reaction or Western blot, respectively. Cell proliferation and apoptosis were analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay or flow cytometry, respectively. Transwell assay was used to determine cell migration and invasion. The interaction between miR-296-5p and NEAT1 or CNN2 was analyzed by dual-luciferase reporter assay and RIP assay. Huh7 cells transfected with sh-NEAT1 were used to establish the murine xenograft model.

Results

NEAT1 was elevated in HCC tissues and cell lines. Knockdown of NEAT1 significantly inhibited proliferation, migration and invasion of HCC cells in vitro as well as tumor growth in vivo. NEAT1 was a sponge of miR-296-5p and remarkably reduced the level of miR-296-5p in HCC cells. Furthermore, NEAT1 silence significantly decreased the expression of CNN2, which was the direct target of miR-296-5p. Besides that, the tumor suppression caused by NEAT1 silence could be rescued by CNN2 restoration or miR-296-5p inhibition in vitro. Additionally, NEAT1 indirectly regulated CNN2 expression by competing to miR-296-5p in vitro and in vivo.

Conclusion

LncRNA NEAT1 contributes to HCC progression by regulating miR-296-5p/CNN2 axis, providing a novel regulatory mechanism for HCC development and a promising therapeutic target for the HCC treatment.

Genetic Profiles Related to Pathogenesis in Sporadic Intracranial Aneurysm Patients

BACKGROUND

Intracranial aneurysm (IA) represents a cerebrovascular disorder that featured by dilation or bulging of the weakened blood vessel wall. When it ruptures, an IA leads to subarachnoid hemorrhage with high disability and mortality rates. Despite the numerous studies focusing on IA ruptures, little research on IA pathogenesis has been reported. In this study, we aimed to reveal key genes related to IA formation.

METHODS

Four datasets from Gene Expression Omnibus data were downloaded, normalized, and separated into the IA group and the normal vessel control group for analyses. We screened for differentially expressed genes (DEGs) between groups and conducted functional enrichment, pathway enrichment, and gene set enrichment analysis analyses among significant DEGs.

RESULTS

according to our analyses, significant DEGs majorly associate with smooth muscle system and the complement system. Among all DEGs, 5 down-regulated genes (MYH11, CNN1, MYOCD, ACTA1, and LMOD1) and 3 up-regulated genes (C1QB, C3AR1, and VSIG4) are most relevant in IA formation.

CONCLUSIONS

Key DEGs identified in this study are related to IA pathogenesis. Among identified DEGs, LMOD1 is the most significant and merits more attention.

Downregulation of calponin 2 contributes to the quiescence of lung macrophages

Calponin 2 is an actin cytoskeleton-associated regulatory protein that inhibits the activity of myosin-ATPase and cytoskeleton dynamics. Recent studies have demonstrated that deletion of calponin 2 restricts the proinflammatory activation of macrophages in atherosclerosis and arthritis to attenuate the disease progression in mice. Here we demonstrate that the levels of calponin 2 vary among different macrophage populations, which may reflect their adaptation to specific tissue microenvironment corresponding to specific functional states. Interestingly, lung resident macrophages express significantly lower calponin 2 than peritoneal resident macrophages, which correlates with decreased substrate adhesion and reduced expression of proinflammatory cytokines and a proresolution phenotype. Deletion of calponin 2 in peritoneal macrophages also decreased substrate adhesion and downregulated the expression of proinflammatory cytokines. Providing the first line of defense against microbial invasion while receiving constant exposure to extrinsic antigens, lung macrophages need to maintain a necessary level of activity while limiting exaggerated inflammatory reaction. Therefore, their low level of calponin 2 may reflect an important physiological adaption. Downregulation of calponin 2 in macrophages may be targeted as a cytoskeleton-based novel mechanism, possibly via endoplasmic reticulum stress altering the processing and secretion of cytokines, to regulate immune response and promote quiescence for the treatment of inflammatory diseases.

Double deletion of calponin 1 and calponin 2 in mice decreases systemic blood pressure with blunted length-tension response of aortic smooth muscle

Calponin is a family of actin filament-associated regulatory proteins. Among its three isoforms, calponin 1 is smooth muscle specific and calponin 2 is expressed in smooth muscle and certain non-muscle cells. Previous studies showed that calponin 1 knockout mice had detectable changes in the contractility of urogenital smooth muscle whereas other smooth muscles were less affected. To investigate the possibility that calponins 1 and 2 have overlapping functions in smooth muscle, we examined the effect of double knockout of calponin 1 and calponin 2 genes (Cnn1 and Cnn2) on smooth muscle functions. The results showed for the first time that calponin 1 and calponin 2 double knockout in mice does not cause lethality. The double knockout mice showed decreased systemic blood pressure, decreased force development and blunted length tension response in endothelial-removed aortic rings. A compensatory increase of calponin 1 was found in smooth muscle of Cnn2-/- mice but not vice versa. Cnn1-/- and Cnn2-/- double knockout aortic smooth muscle exhibits faster relaxation than that of wild type control. Double deletion or co-suppression of calponin 1 and calponin 2 in vascular smooth muscle to blunt myogenic response may present a novel approach to develop new treatment for hypertension.

Calponins Are Recruited to Actin-Rich Structures Generated by Pathogenic Escherichia coli, Listeria, and Salmonella

The ingestion of enteropathogenic Escherichia coli (EPEC), Listeria monocytogenes, or Salmonella enterica serovar Typhimurium leads to their colonization of the intestinal lumen, which ultimately causes an array of ailments ranging from diarrhea to bacteremia. Once in the intestines, these microbes generate various actin-rich structures to attach, invade, or move within the host intestinal epithelial cells. Although an assortment of actin-associated proteins has been identified to varying degrees at these structures, the localization of many actin stabilizing proteins have yet to be analyzed. Here, we examined the recruitment of the actin-associated proteins, calponin 1 and 2 at EPEC pedestals, L. monocytogenes actin clouds, comet tails and listeriopods, and S. Typhimurium membrane ruffles. In other systems, calponins are known to bind to and stabilize actin filaments. In EPEC pedestals, calponin 1 was recruited uniformly throughout the structures while calponin 2 was enriched at the apical tip. During L. monocytogenes infections, calponin 1 was found through all the actin-rich structures generated by the bacteria, while calponin 2 was only present within actin-rich structures formed by L. monocytogenes near the host cell membrane. Finally, both calponins were found within S. Typhimurium-generated membrane ruffles. Taken together, we have shown that although calponin 1 is recruited to actin-rich structures formed by the three bacteria, calponin 2 is specifically recruited to only membrane-bound actin-rich structures formed by the bacteria. Thus, our findings suggest that calponin 2 is a novel marker for membrane-bound actin structures formed by pathogenic bacteria. Anat Rec, 301:2103-2111, 2018. © 2018 Wiley Periodicals, Inc.

Deletion of calponin 2 attenuates the development of calcific aortic valve disease in ApoE-/- mice

Calcific aortic valve disease (CAVD) is a leading cause of cardiovascular mortality and lacks non-surgical treatment. The pathogenesis of CAVD involves perturbation of valvular cells by mechanical stimuli, including shear stress, pressure load and leaflet stretch, of which the molecular mechanism requires further elucidation. We recently demonstrated that knockout (KO) of Cnn2 gene that encodes calponin isoform 2, a mechanoregulated cytoskeleton protein, attenuates atherosclerosis in ApoE KO mice. Here we report that Cnn2 KO also decreased calcification of the aortic valve in ApoE KO mice, an established model of CAVD. Although myeloid cell-specific Cnn2 KO highly effectively attenuated vascular atherosclerosis that shares many pathogenic processes with CAVD, it did not reduce aortic valve calcification in ApoE KO mice. Indicating a function in the pathogenesis of CAVD, calponin 2 participates in myofibroblast differentiation that is a leading step in the development of CAVD. The aortic valves of ApoE KO mice exhibited increased expression of calponin 2 and smooth muscle actin (SMA), a hallmark of myofibroblasts. The expression of calponin 2 increased during myofibroblast-like differentiation of primary sheep aortic valve interstitial cells and during the osteogenic differentiation of mouse myofibroblasts. Cnn2 KO attenuated TGFβ1-induced differentiation of myofibroblasts in culture as shown by the lower expression of SMA and less calcification than that of wild type (WT) cells. These findings present calponin 2 as a novel molecular target for the treatment and prevention of CAVD.

Estrogen relaxes gastric muscle cells via a nitric oxide- and cyclic guanosine monophosphate-dependent mechanism: A sex-associated differential effect

Various gastrointestinal (GI) disorders have a higher prevalence in women than in men. In addition, estrogen has been demonstrated to have an inhibitory effect on the contractility of GI smooth muscle. Although increased plasma estrogen levels have been implicated in GI disorders, the role of gastric estrogen receptor (ER) in these sex-specific differences remains to be fully elucidated. The present study was designed to investigate the sex-associated differences in the expression of the two ER isoforms, ERα and ERβ, and the effect of estrogen on gastric muscle contraction via the nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway. Experiments were performed on single gastric smooth muscle cells (GSMCs) isolated from male and female Sprague Dawley rats. The effect of acetylcholine (ACh), a muscarinic agonist, on the contraction of GSMCs was measured via scanning micrometry in the presence or absence of 1 µM 17β-estradiol (E2), an agonist to the majority of ERs, 1,3,5-tris(4-hydroxyphenyl)-4-propyl-1H-pyrazole (PPT), an ERα agonist, or diarylpropionitrile (DPN), an ERβ agonist. The protein expression levels of ER subtypes in GSMCs were measured using a specifically designed ELISA. GSMCs from female rats had a higher expression of ERα and ERβ protein compared with GSMCs from males. ACh induced less contraction in female that in male GSMCs. Pre-treatment of GSMCs with E2 reduced the contraction of GSMCs from both sexes, but to a greater extent in those from females. PPT and DPN inhibited ACh-induced contraction in GSMCs from females. Furthermore, E2 increased NO and cGMP levels in GSMCs from males and females; however, higher levels were measured in females. Of note, pre-incubation of female GSMCs with Nω-nitro-L-arginine, a NO synthase inhibitor, or 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a guanylyl cyclase inhibitor, reduced the inhibitory effect of estrogen on GSMC contraction. In conclusion, estrogen relaxes GSMCs via an NO/cGMP-dependent mechanism, and the reduced contraction in GSMCs from females by estrogen may be associated with the sex-associated increased expression of ERα and ERβ, and greater production of NO and cGMP, compared with that in GSMCs from males.

Cnn3 regulates neural tube morphogenesis and neuronal stem cell properties

Calponin 3 (Cnn3) is a member of the Cnn family of actin-binding molecules that is highly expressed in the mammalian brain and has been shown to control dendritic spine morphology, density, and plasticity by regulating actin cytoskeletal reorganization and dynamics. However, little is known about the role of Cnn3 during embryonic development. In this study, we analyzed mutant animals deficient in Cnn3 to gain a better understanding of its role in brain morphogenesis. Embryos lacking Cnn3 exhibited massive malformation of the developing brain including exoencephaly, closure defects at the rostral neural tube, and strong enlargement of brain tissue. In wild-type animals, we found Cnn3 being localized to the apical lining of the neuroepithelium in close vicinity to beta-Catenin and N-cadherin. By performing immunohistochemistry on beta-Catenin and p-Smad, and furthermore taking advantage of Wnt-reporter animals, we provide evidence that the loss of Cnn3 during development can affect signaling pathways crucial for correct morphogenesis of the neural tube. In addition, we used embryonic neurosphere cultures to investigate the role of Cnn3 in embryonic neuronal stem cells (NSC). Here, we observed that Cnn3 deficiency in NSCs increased the number of newly formed neurospheres and increased neurosphere size without perturbing their differentiation potential. Together, our study provides evidence for an important role of Cnn3 during development of the embryonic brain and in regulating NSC function.

Lentivirus-mediated shRNA Targeting CNN2 Inhibits Hepatocarcinoma in Vitro and in Vivo

Objective: Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with a high rate of mortality. Our previous study shows the expression of calponin 2 (CNN2) is up-regulated in hepatocellular carcinoma tissues, especially in metastatic ones. To better understand the role of CNN2 in HCC, RNA interference (RNAi) was used to explore its role in tumor growth and metastasis. Methods: Lentivirus-mediated CNN2-shRNA was transfected into SK-hep-1 cells, and the efficacy of CNN2 expression, cell migration, invasion, proliferation and cell cycles were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR), Western blot (WB), Transwell assay, methyl thiazol tetrazolium assay and flow cytometry, respectively. SK-hep-1 cells transfected with Lentivirus-CNN2 shRNA were xenografted in Balb/C nude mice to explore the effect of CNN2-shRNA in tumor growth. Xenograft tumor tissues were examined for their histopathology, cell apoptosis, the expression of total protein and their corresponding phosphorylated protein of MEK1/2, ERK1/2, AKT, by hematoxylin and eosin stain (H & E staining), TUNEL assay, immunohistochemical technique, respectively. Results: Our research shows it is evident that CNN2 shRNA can effectively down-regulate the expressions of CNN2 mRNA and protein, inhibit cell proliferations, arrest cell cycles at the S phase and reduce cell migration and invasion. SK-hep-1 cells with CNN2 down-regulation have markedly attenuated tumor growth in nude mice. Xenograft tumor tissues have displayed typical tumor characteristics and no apoptosis is detected in shRNA group or in control group. No metastatic tumor was found in any group of nude mice. With CNN2 protein down-regulation, the protein of pMEK1/2 and pERK1/2 are effectively down-regulated, except pAKT, AKT, MEK1/2 and ERK1/2. Conclusions: CNN2 plays an important role in tumor growth and metastasis, possibly through MEK1/2-ERK1/2 signaling pathway. Our study illustrate that CNN2 might be a potential target in HCC molecular target therapy.

Knockdown of calponin 2 suppressed cell growth in gastric cancer cells

Calponin family members are actin filament-associated regulatory proteins with distinct expression patterns. Previous studies on CNN2 (calponin 2) have demonstrated that CNN2 is expressed in a broad range of tissues and cell types, exhibiting potential regulatory roles in a number of cellular activities, including cell proliferation, cell migration, and platelet adhesion. In this work, we found that both messenger RNA and protein expression levels of CNN2 were remarkably upregulated in 60%-70% of gastric cancer tissues by comparison with those of neighboring non-tumorous mucosa. By utilizing specific shCNN2 (small hairpin RNA targeting CNN2), the potential role of CNN2 in regulating AGS gastric cancer cell growth was then further investigated. AGS cells infected with shCNN2 exhibited significantly decreased cell growth ability by comparison with control cells in vitro. Moreover, while there was no obvious difference in cell cycle distribution between two groups, enhanced cell apoptosis was detected in cells with reduced CNN2 expression. Consistently, caspase 3/7 activity was also remarkably activated upon shCNN2 lentivirus infection. Taken together, our results demonstrated that knockdown of endogenous CNN2 in AGS cells could significantly activate cell apoptosis pathway and therefore suppress cell growth in vitro. The deletion of CNN2 might be a potential therapeutic approach to inhibit aggressive growth of gastric cancer.

The role of MACF1 in nervous system development and maintenance

Microtubule-actin crosslinking factor 1 (MACF1), also known as actin crosslinking factor 7 (ACF7), is essential for proper modulation of actin and microtubule cytoskeletal networks. Most MACF1 isoforms are expressed broadly in the body, but some are exclusively found in the nervous system. Consequentially, MACF1 is integrally involved in multiple neural processes during development and in adulthood, including neurite outgrowth and neuronal migration. Furthermore, MACF1 participates in several signaling pathways, including the Wnt/β-catenin and GSK-3 signaling pathways, which regulate key cellular processes, such as proliferation and cell migration. Genetic mutation or dysregulation of the MACF1 gene has been associated with neurodevelopmental and neurodegenerative diseases, specifically schizophrenia and Parkinson's disease. MACF1 may also play a part in neuromuscular disorders and have a neuroprotective role in the optic nerve. In this review, the authors seek to synthesize recent findings relating to the roles of MACF1 within the nervous system and explore potential novel functions of MACF1 not yet examined.

Increased expression of calponin 2 is a positive prognostic factor in pancreatic ductal adenocarcinoma

Calponin 2 plays an important role in regulating actin cytoskeleton, which is critical for cell division and migration. Previous studies have demonstrated that calponin 2 inhibits prostate cancer cell proliferation and metastasis. However, the role of calponin 2 in pancreatic tumor growth, metastasis and patient survival remains unclear. Here, we demonstrate that the level of calponin 2 is a positive prognostic factor for patients with pancreatic ductal adenocarcinoma (PDAC). Patients with high calponin 2 expression in the tumor presented less lymph node metastasis and longer survival. Knockdown of calponin 2 facilitated pancreatic cancer cell proliferation and metastasis. Further experiments suggested that PI3K/AKT, NF-κB, Vimentin, Fibronectin, Snail and Slug were upregulated and E-cadherin was downregulated after calponin 2 was knocked down, implicating altered functions in PDAC proliferation and metastasis. In addition, we verified that calponin 2 functioned through inhibiting PI3K/AKT and NF-κB pathways. Our study suggests that the upregulation of calponin 2 in PDAC correlates to lower malignancy and presents a novel target for the development of new treatment.

RhBMP-2 loaded MBG/PEGylated poly(glycerol sebacate) composite scaffolds for rapid bone regeneration

An rhBMP-2 loaded MBG/PEGS composite scaffold with optimal performances and rapid osteoinductive capacity was successfully designed and fabricated.

Aberrant Expression of microRNA-9 Contributes to Development of Intracranial Aneurysm by Suppressing Proliferation and Reducing Contractility of Smooth Muscle Cells

BACKGROUND MiR-9 is reportedly involved with many diseases, such as acute myeloid leukemia and liver oncogenesis. In the present study we investigated the molecular mechanism, including the potential regulator and signaling pathways, of MYOCD, which is the gene that in humans encodes the protein myocardin. MATERIAL AND METHODS We searched the online miRNA database (www.mirdb.org) with the "seed sequence" located within the 3'-UTR of the target gene, and then validated MYOCD to be the direct gene via luciferase reporter assay system, and further confirmed it in cultured cells by using Western blot analysis and realtime PCR. RESULTS We established the negative regulatory relationship between miR-9 and MYOCD via studying the relative luciferase activity. We also conducted realtime PCR and Western blot analysis to study the mRNA and protein expression level of MYOCD between different groups (intracranial aneurysm vs. normal control) or cells treated with scramble control, miR-9 mimics, MYOCD siRNA, and miR-9 inhibitors, indicating the negative regulatory relationship between miR-9 and MYOCD. We also investigated the relative viability of smooth muscle cells when transfected with scramble control, miR-9 mimics, MYOCD siRNA, and miR-9 inhibitors to validate that miR-9 t negatively interferes with the viability of smooth muscle cells. We then investigated the relative contractility of smooth muscle cells when transfected with scramble control, miR-9 mimics, MYOCD siRNA, and miR-9 inhibitors, and the results showed that miR-9 weakened contractility. CONCLUSIONS Our findings show that dysregulation of miR-9 is responsible for the development of IA via targeting MYOCD. miR-9 and its direct target, MYOCD, might novel therapeutic targets in the treatment of IA.

Deletion of Calponin 2 in Mouse Fibroblasts Increases Myosin II-Dependent Cell Traction Force

Cell traction force (CTF) plays a critical role in controlling cell shape, permitting cell motility, and maintaining cellular homeostasis in many biological processes such as angiogenesis, development, wound healing, and cancer metastasis. Calponin is an actin filament-associated cytoskeletal protein in smooth muscles and multiple types of non-muscle cells. An established biochemical function of calponin is the inhibition of myosin ATPase in smooth muscle cells. Vertebrates have three calponin isoforms. Among them, calponin 2 is expressed in epithelial cells, endothelial cells, macrophages, myoblasts, and fibroblasts and plays a role in regulating cytoskeleton activities such as cell adhesion, migration, and cytokinesis. Knockout (KO) of the gene encoding calponin 2 (Cnn2) in mice increased cell motility, suggesting a function of calponin 2 in modulating CTF. In this study, we examined fibroblasts isolated from Cnn2 KO and wild-type (WT) mice using CTF microscopy. Primary mouse fibroblasts were cultured on polyacrylamide gel substrates embedded with fluorescent beads to measure root-mean-square traction, total strain energy, and net contractile movement. The results showed that calponin 2-null fibroblasts exhibit traction force greater than that of WT cells. Adherent calponin 2-null fibroblasts de-adhered faster than the WT control during mild trypsin treatment, consistent with an increased CTF. Blebbistatin, an inhibitor of myosin II ATPase, is more effective upon an alteration in cell morphology when calponin 2 is present in WT fibroblasts than that on Cnn2 KO cells, indicating their additive effects in inhibiting myosin motor activity. The novel finding that calponin 2 regulates myosin-dependent CTF in non-muscle cells demonstrates a mechanism for controlling cell motility-based functions.

Deletion of calponin 2 in macrophages alters cytoskeleton-based functions and attenuates the development of atherosclerosis

Arterial atherosclerosis is an inflammatory disease. Macrophages play a major role in the pathogenesis and progression of atherosclerotic lesions. Modulation of macrophage function is a therapeutic target for the treatment of atherosclerosis. Calponin is an actin-filament-associated regulatory protein that inhibits the activity of myosin-ATPase and dynamics of the actin cytoskeleton. Encoded by the gene Cnn2, calponin isoform 2 is expressed at significant levels in macrophages. Deletion of calponin 2 increases macrophage migration and phagocytosis. In the present study, we investigated the effect of deletion of calponin 2 in macrophages on the pathogenesis and development of atherosclerosis. The results showed that macrophages isolated from Cnn2 knockout mice ingested a similar level of acetylated low-density lipoprotein (LDL) to that of wild type (WT) macrophages but the resulting foam cells had significantly less hindered velocity of migration. Systemic or myeloid cell-specific Cnn2 knockouts effectively attenuated the development of arterial atherosclerosis lesions with less macrophage infiltration in apolipoprotein E knockout mice. Consistently, calponin 2-null macrophages produced less pro-inflammatory cytokines than that of WT macrophages, and the up-regulation of pro-inflammatory cytokines in foam cells was also attenuated by the deletion of calponin 2. Calponin 2-null macrophages and foam cells have significantly weakened cell adhesion, indicating a role of cytoskeleton regulation in macrophage functions and inflammatory responses, and a novel therapeutic target for the treatment of arterial atherosclerosis.

Deletion of calponin 2 in macrophages attenuates the severity of inflammatory arthritis in mice

Calponin is an actin cytoskeleton-associated protein that regulates motility-based cellular functions. Three isoforms of calponin are present in vertebrates, among which calponin 2 encoded by the Cnn2 gene is expressed in multiple types of cells, including blood cells from the myeloid lineage. Our previous studies demonstrated that macrophages from Cnn2 knockout (KO) mice exhibit increased migration and phagocytosis. Intrigued by an observation that monocytes and macrophages from patients with rheumatoid arthritis had increased calponin 2, we investigated anti-glucose-6-phosphate isomerase serum-induced arthritis in Cnn2-KO mice for the effect of calponin 2 deletion on the pathogenesis and pathology of inflammatory arthritis. The results showed that the development of arthritis was attenuated in systemic Cnn2-KO mice with significantly reduced inflammation and bone erosion than that in age- and stain background-matched C57BL/6 wild-type mice. In vitro differentiation of calponin 2-null mouse bone marrow cells produced fewer osteoclasts with decreased bone resorption. The attenuation of inflammatory arthritis was confirmed in conditional myeloid cell-specific Cnn2-KO mice. The increased phagocytotic activity of calponin 2-null macrophages may facilitate the clearance of autoimmune complexes and the resolution of inflammation, whereas the decreased substrate adhesion may reduce osteoclastogenesis and bone resorption. The data suggest that calponin 2 regulation of cytoskeleton function plays a novel role in the pathogenesis of inflammatory arthritis, implicating a potentially therapeutic target.

Knockdown of microtubule actin crosslinking factor 1 inhibits cell proliferation in MC3T3-E1 osteoblastic cells

Microtubule actin crosslinking factor 1 (MACF1), a widely expressed cytoskeletal linker, plays important roles in various cells by regulating cytoskeleton dynamics. However, its role in osteoblastic cells is not well understood. Based on our previous findings that the association of MACF1 with F-actin and microtubules in osteoblast-like cells was altered under magnetic force conditions, here, by adopting a stable MACF1-knockdown MC3T3-E1 osteoblastic cell line, we found that MACF1 knockdown induced large cells with a binuclear/multinuclear structure. Further, immunofluorescence staining showed disorganization of F-actin and microtubules in MACF1-knockdown cells. Cell counting revealed significant decrease of cell proliferation and cell cycle analysis showed an S phase cell cycle arrest in MACF1-knockdown cells. Moreover and interestingly, MACF1 knockdown showed a potential effect on cellular MTT reduction activity and mitochondrial content, suggesting an impact on cellular metabolic activity. These results together indicate an important role of MACF1 in regulating osteoblastic cell morphology and function. [BMB Reports 2015; 48(10): 583-588]

Calponin isoforms CNN1, CNN2 and CNN3: Regulators for actin cytoskeleton functions in smooth muscle and non-muscle cells

Calponin is an actin filament-associated regulatory protein expressed in smooth muscle and many types of non-muscle cells. Three homologous genes, CNN1, CNN2 and CNN3, encoding calponin isoforms 1, 2, and 3, respectively, are present in vertebrate species. All three calponin isoforms are actin-binding proteins with functions in inhibiting actin-activated myosin ATPase and stabilizing the actin cytoskeleton, while each isoform executes different physiological roles based on their cell type-specific expressions. Calponin 1 is specifically expressed in smooth muscle cells and plays a role in fine-tuning smooth muscle contractility. Calponin 2 is expressed in both smooth muscle and non-muscle cells and regulates multiple actin cytoskeleton-based functions. Calponin 3 participates in actin cytoskeleton-based activities in embryonic development and myogenesis. Phosphorylation has been extensively studied for the regulation of calponin functions. Cytoskeleton tension regulates the transcription of CNN2 gene and the degradation of calponin 2 protein. This review summarizes our knowledge learned from studies over the past three decades, focusing on the evolutionary lineage of calponin isoform genes, their tissue- and cell type-specific expressions, structure-function relationships, and mechanoregulation.

Comparison of human dental follicle cells and human periodontal ligament cells for dentin tissue regeneration

AIM

To compare the odontogenic potential of human dental follicle cells (DFCs) and periodontal ligament cells (PDLCs).

MATERIALS & METHODS

In vitro and in vivo characterization studies of DFCs and PDLCs were performed comparatively. DFCs and PDLCs were subcutaneously implanted into the dorsum of mice for 8 weeks after combined with treated dentin matrix scaffolds respectively.

RESULTS

Proteomic analysis identified 32 differentially expressed proteins in DFCs and PDLCs. Examination of the harvested grafts showed PDLCs could form the dentin-like tissues as DFCs did. However, the structure of dentin tissues generated by DFCs was more complete.

CONCLUSION

PDLCs could contribute to regenerate dentin-like tissues in the inductive microenvironment of treated dentin matrix. DFCs presented more remarkable dentinogenic capability than PDLCs did.

The role of the RhoA/ROCK pathway in gender-dependent differences in gastric smooth muscle contraction

Gender-related differences in various gastric functions and diseases have been reported, with women having a higher prevalence of gastrointestinal disturbances than men. The aim of this study was to investigate sex-dependent differences in activation of the Rho-associated protein kinase (ROCK; RhoA/Rho kinase) pathway and muscle contraction in the stomach using single gastric smooth muscle cells (GSMC) from male and female Sprague-Dawley rats. Expression of ROCK1 and ROCK2 protein and acetylcholine (ACh)-induced activation of RhoA and ROCK were measured using a specifically designed enzyme-linked immunosorbent assay and activity assay kits, respectively. Contraction of a single GSMC was measured by scanning micrometry in the presence or absence of the ROCK inhibitor Y27632 dihydrochloride. ACh-induced activation of RhoA and ROCK and subsequent contraction were greater in male rats than in female rats but neither was related to differences in the expression of ROCK1 or ROCK2 or total RhoA amount. Most important, Y27632 inhibited and abolished differences in ACh-induced contraction in both sexes. In conclusion, increased ACh-induced contraction in the GSMC of male rats is attributable to greater RhoA/ROCK activation independent of differences in the expression of ROCK isoforms or total RhoA.

Calponin-h2 is upregulated in the tissues and plasma of patients with breast cancer

Increasing evidence has demonstrated that changes in plasma nuclear matrix proteins are specific markers of cancer. Furthermore, proteomic analysis has revealed that calponin-h2 is upregulated in human breast cancer tissue, but is absent in healthy and benign controls. However, the roles of levels of plasma calponin-h2 in the diagnosis of breast cancer and its association with clinicopathological parameters remain to be elucidated. In the present study, the plasma levels of calponin-h2 in patients with breast cancer, benign breast disease and in healthy controls were examined using an enzyme-linked immunosorbent assay. The expression levels of calponin-h2 in invasive breast cancer and normal breast tissues were measured using immunohistochemistry. Statistical analyses examined the association between the levels of plasma calponin-h2 and clinicopathological parameters. The results demonstrated that the plasma level of calponin-h2 in breast cancer was significantly higher than those in the healthy control and benign breast disease groups (P<0.05). The combination of calponin-h2, carcinoembryonic antigen, carbohydrate antigen 15-3 improved the diagnosis of breast cancer. The plasma levels of calponin-h2 PR-breast cancers was significantly higher, compared with PR+ breast cancers (P=0.033), and the plasma levels of calponin-h2 in patients with breast cancer aged >50 years was significantly higher than in patients ≤ 50 years of age (P=0.001). No association was found between the level of plasma calponin-h2 and other clinicopathological parameters of breast cancer. Taken together, these results indicated that calponin-h2 may be a useful marker of breast cancer.

Regulation of smooth muscle contractility by competing endogenous mRNAs in intracranial aneurysms

Alterations in vascular smooth muscle cells (SMCs) contribute to the pathogenesis of intracranial aneurysms (IAs), but the genetic mechanisms underlying these alterations are unclear. We used microarray analysis to compare tissue small noncoding RNA and messenger RNA expression profiles in vessel wall samples from patients with late-stage IAs. We identified myocardin (MYOCD), a key contractility regulator of vascular SMCs, as a critical factor in IA progression. Using a multifaceted computational and experimental approach, we determined that depletion of competitive endogenous RNAs (ARHGEF12, FGF12, and ADCY5) enhanced factors that downregulate MYOCD, which induces the conversion of SMCs from differentiated contractile states into dedifferentiated phenotypes that exhibit enhanced proliferation, synthesis of new extracellular matrix, and organization of mural thrombi. These effects may lead to the repair and maintenance of IAs. This study presents guidelines for the prediction and validation of the IA regulator MYOCD in competitive endogenous RNA networks and facilitates the development of novel therapeutic and diagnostic tools for IAs.

Caveolin-3 Promotes a Vascular Smooth Muscle Contractile Phenotype

Epidemiological studies have demonstrated the importance of cardiovascular diseases in Western countries. Among the cell types associated with a dysfunctional vasculature, smooth muscle (SM) cells are believed to play an essential role in the development of these illnesses. Vascular SM cells are key regulators of the vascular tone and also have an important function in the development of atherosclerosis and restenosis. While in the normal vasculature, contractile SM cells are predominant, in atherosclerotic vascular lesions, synthetic cells migrate toward the neointima, proliferate, and synthetize extracellular matrix proteins. In the present study, we have examined the role of caveolin-3 in the regulation of SM cell phenotype. Caveolin-3 is expressed in vivo in normal arterial SM cells, but its expression appears to be lost in cultured SM cells. Our data show that caveolin-3 expression in the A7r5 SM cell line is associated with increased expression of contractility markers such as SM α-actin, SM myosin heavy chain but decreased expression of the synthetic phenotype markers such as p-Elk and Klf4. Moreover, we also show that caveolin-3 expression can reduce proliferation upon treatment with LDL or PDGF. Finally, we show that caveolin-3-expressing SM cells are less sensitive to apoptosis than control cells upon treatment with oxidized LDL. Taken together, our data suggest that caveolin-3 can regulate the phenotypic switch between contractile and synthetic SM cells. A better understanding of the factors regulating caveolin-3 expression and function in this cell type will permit the development of a better comprehension of the factors regulating SM function in atherosclerosis and restenosis.

Proteomic profile of pre - B2 lymphoblasts from children with acute lymphoblastic leukemia (ALL) in relation with the translocation (12; 21)

Background

Until now, the major prognostic factors for pediatric acute lymphoblastic leukemia (ALL), age, white blood cell count and chromosomal alterations are initially taken into account for the risk stratification of patients. In the light of protein marker studies to classify subtypes of Acute Myeloblastic Leukemia efficiently, we have compared the lymphoblastes proteome in Childhood ALL in accordance with the presence of t(12;21), indicator of good prognosis, usually.

Methods

Protein expression in pre-B2 lymphoblastic cells, collected from residual bone marrow cells after diagnostic procedures, was analyzed using two dimensional gel electrophoresis protocol. Protein spots whose average normalized volumes were statistically different in the two patients groups (n = 13; student t test p < 0.01), were excised. Tryptic peptides were then analyzed using a nano-LC1200 system coupled to a 6340 Ion Trap mass spectrometer equipped with a HPLC-chip cube interface. The tandem mass spectrometry peak lists extracted using the DataAnalysis program, were compared with the protein database Mascot Daemon.

Results

We focused on twelve spots corresponding to sixteen identified candidate proteins among the 26 found differentially expressed (p ≤ 0.05) regarding the presence of t(12;21). Among over expressed proteins, two proteins were implicated in cellular growth arrest (i.e. calponine 2, p ≤ 0.001 and phosphatidylinositol transfer protein beta, p ≤ 0.001) in accordance with good prognosis, while two other proteins favored cell cycle proliferation (i.e. methionine adenosyl transferase 2β, p ≤ 0.005 and heterogeneous nuclear ribonucleo-proteins A2 p ≤ 0.01) and could therefore be good marker candidates of aggressiveness. Level of expression of proteasome subunit beta type-2 (p ≤ 0.01) and protein casein kinase 2α (p ≤ 0.01) which both favored apoptosis, deubiquitinating enzyme OTUB1 (p ≤ 0.05) and MLL septin-like fusion protein MSF-B, septin 9 i4 (p ≤ 0.01) were in accord with a good prognosis related to t(12;21) lymphoblasts.

Conclusion

By drawing up the protein map of leukemic cells, these new data identified marker candidates of leukemic aggressiveness and new t(12;21) patients subgroups. These preliminary results will be in the near future confirmed by using a larger sample of pre-B2 childhood ALLs from national lymphoblastic cell collections.

Diminished expression of h2-calponin in prostate cancer cells promotes cell proliferation, migration and the dependence of cell adhesion on substrate stiffness

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Calponin is an actin filament-associated protein and its h2 isoform inhibits cell motility.

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H2-calponin expression is strong in prostate epithelial cells and diminished in cancerous cells.

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Low h2-calponin metastatic prostate cancer cells had faster rates of cell proliferation and migration.

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Low h2-calponin metastatic prostate cancer cells showed reduced substrate adhesion.

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Low h2-calponin prostate cancer cells had a higher dependence on substrate stiffness.

Calponin is an actin filament-associated protein and its h2 isoform inhibits cell motility. Here we report significant expression of h2-calponin in prostate epithelial cells, which is diminished in cancerous cells. Comparison between a prostate cancer cell line PC3 and its metastatic derivative PC3-M showed lower levels of h2-calponin in PC3-M, corresponding to faster rates of cell proliferation and migration. Substrate adhesion of PC3 and PC3-M cells was positively correlated to the level of h2-calponin and the adhesion of PC3-M exhibited a higher dependence on substrate stiffness. Such effects of h2-calponin on cell proliferation, migration and substrate adhesion were also seen in normal versus cancerous primary prostate cells. Further supporting the role of h2-calponin in inhibiting cell motility, fibroblasts isolated from h2-calponin knockout mice proliferated and migrated faster than that of wild type fibroblasts. Transfective over-expression of h2-calponin in PC3-M cells effectively inhibited cell proliferation and migration. The results suggest that the diminished expression of h2-calponin in prostate cancer cells increases cell motility, decreases substrate adhesion, and promotes adhesion on high stiffness substrates.

Calponin1 inhibits dilated cardiomyopathy development in mice through the εPKC pathway

BACKGROUND

Calponin1 (CNN1) is involved in the regulation of smooth muscle contraction in physiological situation and it also expresses abnormally in a variety of pathological situations. We found that the expression of CNN1 decreased significantly in the heart tissue of a cTnT(R141W) transgenic dilated cardiomyopathy (DCM) mouse model and an adriamycin (ADR)-induced DCM mouse model, suggesting that CNN1 is involved in the pathogenesis of DCM. However, the role of CNN1 on cardiac function, especially on pathogenesis of DCM, has not been clarified. In this study, we tested whether rescued expression of CNN1 could prevent the development of DCM and investigated its possible mechanisms.

METHODS AND RESULTS

The DCM phenotypes were significantly improved with the transgenic expression of CNN1 in the cTnT(R141W)×CNN1 double transgenic (DTG) mice, which was demonstrated by the survival, cardiac geometry and function analyses, as well as microstructural and ultrastructural observations based on echocardiography and histology examination. The expression of CNN1 could also resist the cardiac geometry breakage and dysfunction in the ADR-induced DCM mice model. Meanwhile, the epsilon isoform of protein kinase C (εPKC) activator and inhibitor could reverse the activation of εPKC/ERK/mTOR pathway and DCM phenotypes in the cTnT(R141W) and cTnT(R141W)×CNN1 double transgenic (DTG) mice.

CONCLUSIONS

εPKC/ERK/mTOR pathway activation induced by the rescued expression of CNN1 contributed to the improvement of cardiac dysfunction and pathological changes observed in the DTG mice. CNN1 could be a therapeutic target to prevent the development of DCM and heart failure (HF).

Mechanism of calponin stabilization of cross-linked actin networks

The actin-binding protein calponin has been previously implicated in actin cytoskeletal regulation and is thought to act as an actin stabilizer, but the mechanism of its function is poorly understood. To investigate this underlying physical mechanism, we studied an in vitro model system of cross-linked actin using bulk rheology. Networks with basic calponin exhibited a delayed onset of strain stiffening (10.0% without calponin, 14.9% with calponin) and were able to withstand a higher maximal strain before failing (35% without calponin, 56% with calponin). Using fluorescence microscopy to study the mechanics of single actin filaments, we found that calponin increased the flexibility of actin filaments, evident as a decrease in persistence length from 17.6 μm without to 7.7 μm with calponin. Our data are consistent with current models of affine strain behavior in semiflexible polymer networks, and suggest that calponin stabilization of actin networks can be explained purely by changes in single-filament mechanics. We propose a model in which calponin stabilizes actin networks against shear through a reduction of persistence length of individual filaments.

Mechanoregulation of h2-calponin gene expression and the role of Notch signaling

The essential role of mechanical signals in regulating the function of living cells is universally observed. However, how mechanical signals are transduced in cells to regulate gene expression is largely unknown. We previously demonstrated that the gene encoding h2-calponin (Cnn2) is sensitively regulated by mechanical tension. In the present study, mouse genomic DNA containing the Cnn2 promoter was cloned, and a nested set of 5' truncations was studied. Transcriptional activity of the Cnn2 promoter-reporter constructs was examined in transfected NIH/3T3, HEK293, and C2C12 cells for their responses to the stiffness of culture substrate. The results showed significant transcriptional activities of the -1.00- and -1.24-kb promoter constructs, whereas the -0.61-kb construct was inactive. The -1.38-, -1.57-, and -2.12-kb constructs showed higher transcriptional activity, whereas only the -1.57- and -2.12-kb constructs exhibited repression of expression when the host cells were cultured on low stiffness substrate. Internal deletion of the segment between -1.57 and -1.38 kb in the -2.12-kb promoter construct abolished the low substrate stiffness-induced repression. Site-specific deletion or mutation of an HES-1 transcription factor binding site in this region also abolished this repression effect. The level of HES-1 increased in cells cultured under a low tension condition, corresponding to the down-regulation of h2-calponin. h2-Calponin gene expression is further affected by the treatment of cells with Notch inhibitor and activator, suggesting an upstream signaling mechanism.

Advanced diabetic nephropathy with nephrotic range proteinuria: a pilot study of the long-term efficacy of subcutaneous ACTH gel on proteinuria, progression of CKD, and urinary levels of VEGF and MCP-1

BACKGROUND AND OBJECTIVE

Adrenocorticotropic hormone (ACTH) is able to reduce proteinuria in nondiabetic glomerulopathies through activation of melanocortin receptors (MCR) expressed in the podocyte. To determine the efficacy of ACTH, we conducted a randomized, open-label pilot trial of ACTH gel in patients with advanced diabetic nephropathy.

STUDY DESIGN

Twenty-three (23) patients with diabetic nephropathy were randomized to daily subcutaneous (SQ) injections of 16 or 32 units of ACTH gel for six months. Outcome. The primary endpoint was the percentage of patients achieving a complete remission (<300 mg/24 hours) within 6 months. Exploratory endpoints included the percentage of partial (50% reduction) remissions, changes in Cr, and urinary cytokine markers.

RESULTS

After 6 months of ACTH gel therapy, 8 of 14 (57%) patients achieved a complete (n = 1) or partial (n = 7) remission. In the low-dose ACTH gel group (16 units), urinary protein fell from 6709 + 953 to 2224 + 489 mg/24 hrs (P < 0.001). In contrast, 2 of 6 patients in the 32-unit group achieved partial remission, but aggregate proteinuria (5324 + 751 to 5154 + 853 mg/24 hours) did not change. Urinary VEGF increased from 388 to 1346 pg/mg urinary creatinine (P < 0.02) in the low-dose group but remained unchanged in the high-dose group.

CONCLUSION

ACTH gel stabilizes renal function and reduces urinary protein for up to 6 months after treatment. The ClinTrials.gov identifier is NCT01028287.

Differentiated markers in undifferentiated cells: expression of smooth muscle contractile proteins in multipotent bone marrow mesenchymal stem cells

In studying the differentiation of stem cells along smooth muscle lineage, smooth muscle cell (SMC) contractile proteins serve as markers for the relative state of maturation. Yet, recent evidence suggests that some SMC markers are probably expressed in multipotent mesenchymal stem cells (MSCs). Such a paradox necessitates investigations to re-examine their role as differentiated markers in MSCs. We tried to detect the expression of four widely used SMC markers including α-smooth muscle actin (α-SMA), h1-calponin, desmin and smooth muscle myosin heavy chain (SM-MHC), as well as the other isoforms of calponin family in resting MSCs. Then we used three different conditions to initiate MSCs differentiation along SMC lineage, and examined the alternation of SMC markers expression at both the transcript level and protein level. Desmin and h1-calponin are expressed in MSCs, in the presence or absence of SMC induction conditions. Moreover, MSCs are shown to express all known isoforms of calponin. Double-staining reveals that h1-calponin +/α-SMA - cells constitute the majority of resting MSCs. Under differentiated conditions, expression of SM-MHC was initiated and expression of α-SMA was promoted. The expression of SM-MHC and upregulation of α-SMA are relatively reliable indications of a mature smooth muscle phenotype in MSCs. Given that the cells are particularly rich in calponins expression, we postulate possible roles of these proteins in regulating cellular function by taking part in actin cytoskeleton and signaling. These findings imply that an extensive study of the cell physiology of MSCs should focus on the functional roles for these proteins, rather than simply regard them as differentiated markers.

Androgen-responsive serum response factor target genes regulate prostate cancer cell migration

Progression of prostate cancer (CaP) relies on androgen receptor (AR) signaling, but AR-dependent events that underlie the lethal phenotype remain unknown. Recently, an indirect mechanism of androgen action in which effects of AR on CaP cells are mediated by Serum Response Factor (SRF) has been identified. This is the first mode of androgen action to be associated with aggressive CaP and disease recurrence. The manner in which androgen-responsive SRF activity controls aggressive CaP cell behavior is unknown. Here, the contribution of two representative SRF effector genes that are underexpressed, calponin 2 (CNN2), or overexpressed, sidekick-homolog 1 (SDK1), in clinical CaP specimens is studied. AR- and SRF- dependency of CNN2 and SDK1 expression was verified using synthetic and natural androgens, antiandrogens, and small interfering RNAs targeting AR or SRF, and evaluating the kinetics of androgen induction and SRF binding to endogenously and exogenously expressed regulatory gene regions in AR-positive CaP model systems that mimic the transition from androgen-stimulated to castration-recurrent disease. Small interfering RNA-mediated deregulation of CNN2 or SDK1 expression did not affect CaP cell proliferation or apoptosis but had marked effects on CaP cell morphology and actin cytoskeleton organization. Loss of CNN2 induced cellular protrusions and increased CaP cell migration, whereas silencing of SDK1 led to cell rounding and blunted CaP cell migration. Changes in cell migration did not involve epithelial-mesenchymal transition but correlated with altered β1-integrin expression. Taken together, individual androgen-responsive SRF target genes affect CaP cell behavior by modulating cell migration, which may have implications for therapeutic intervention downstream of AR and SRF.

Phosphorylation of h1 calponin by PKC epsilon may contribute to facilitate the contraction of uterine myometrium in mice during pregnancy and labor

BACKGROUND

The timely onset of powerful uterine contractions during parturition occurs through thick and thin filament interactions, similar to other smooth muscle tissues. Calponin is one of the thin filament proteins. Phosphorylation of calponin induced by PKC-epsilon can promote the contraction of vascular smooth muscle. While the mechanism by which calponin regulates the contraction of pregnant myometrium has rarely been explored. Here, we explore whether PKC-epsilon/h1 calponin pathway contribute to regulation of myometrial contractility and development of parturition.

METHODS

We detected the expression of h1 calponin, phosphorylated h1 calponin, PKC-epsilon and phosphorylated PKC-epsilon in the different stages of mice during pregnancy and in labor by the method of western blot and recorded the contraction activity of myometrium strips at the 19th day during pregnancy with different treatments by the organ bath experiments.

RESULTS

The level of the four proteins including h1 calponin, phosphorylated h1 calponin, PKC-epsilon and phosphorylated PKC-epsilon was significantly increased in pregnant mice myometrium as compared with that in nonpregnant mice. The ratios of phosphorylated h1 calponin/h1 calponin and phosphorylated PKC-epsilon/PKC-epsilon were reached the peak after the onset of labor in myometrium in the mice. After the treatment of more than 10(9-) mol/L Psi-RACK (PKC-epsilon activator), the contractility of myometrium strips from mice was reinforced and the level of phosphorylated h1 calponin increased at the same time which could be interrupted by the specific inhibitor of PKC-epsilon. Meanwhile, the change of the ratio of phosphorylated h1 calponin/h1 calponin was consistent with that of contraction force of mice myometrium strips.

CONCLUSIONS

These data suggest that in mice myometrium, phosphorylation of h1 calponin induced by the PKC-epsilon might facilitate the contraction of uterine in labor and regulate pregnant myometrial contractility.