Desmin Protein Research Articles

Structural alterations and inflammation in the heart after multiple trauma followed by reamed versus non-reamed femoral nailing.

BackgroundApproximately 30,000 patients with blunt cardiac trauma are recorded each year in the United States. Blunt cardiac injuries after trauma are associated with a longer hospital stay and a poor overall outcome. Organ damage after trauma is linked to increased systemic release of pro-inflammatory cytokines and damage-associated molecular patterns. However, the interplay between polytrauma and local cardiac injury is unclear. Additionally, the impact of surgical intervention on this process is currently unknown. This study aimed to determine local cardiac immunological and structural alterations after multiple trauma. Furthermore, the impact of the chosen fracture stabilization strategy (reamed versus non-reamed femoral nailing) on cardiac alterations was studied.Experimental approach15 male pigs were either exposed to multiple trauma (blunt chest trauma, laparotomy, liver laceration, femur fracture and haemorrhagic shock) or sham conditions. Blood samples as well as cardiac tissue were analysed 4 h and 6 h after trauma. Additionally, murine HL-1 cells were exposed to a defined polytrauma-cocktail, mimicking the pro-inflammatory conditions after multiple trauma in vitro.ResultsAfter multiple trauma, cardiac structural changes were observed in the left ventricle. More specifically, alterations in the alpha-actinin and desmin protein expression were found. Cardiac structural alterations were accompanied by enhanced local nitrosative stress, increased local inflammation and elevated systemic levels of the high-mobility group box 1 protein. Furthermore, cardiac alterations were observed predominantly in pigs that were treated by non-reamed intramedullary reaming. The polytrauma-cocktail impaired the viability of HL-1 cells in vitro, which was accompanied by a release of troponin I and HFABP.DiscussionMultiple trauma induced cardiac structural alterations in vivo, which might contribute to the development of early myocardial damage (EMD). This study also revealed that reamed femoral nailing (reamed) is associated with more prominent immunological cardiac alterations compared to nailing without reaming (non-reamed). This suggests that the choice of the initial fracture treatment strategy might be crucial for the overall outcome as well as for any post-traumatic cardiac consequences.

The effect of sodium chloride levels on the taste and texture of dry-cured ham

In order to investigate the effect of NaCl levels (1.5%, 3.5%, 5.5% and 13%) on the taste and texture of dry-cured ham, TPA, myofibril ultrastructure, proteolysis index and free amino acids were evaluated. The proteolysis index (30.76% ± 2.05–11.88% ± 1.90), cohesiveness (0.74 ± 0.04–0.60 ± 0.01), springiness (0.83 ± 0.03–0.71 ± 0.04), and the total free amino acids (9885.3 mg/100 g ± 677.98–3505.15 mg/100 g ± 378.20) decreased with the increase of salt addition, while the hardness (8701.99 g ± 513.37–12057.53 g ± 783.89) and adhesiveness (− 15.73 ± 2.53 to − 32.01 ± 4.95) increased with the increase of salt addition. The myofibril ultrastructure indicated that hams with higher proteolysis index (> 20%) showed more obvious degradation of M-line and Z-disk, and more disordered fiber structure, which was closely related to the degradation of myofibrillar proteins (actin, desmin and troponin-T). Among four groups, the dry-cured ham with 5.5% salt had the highest levels of moisture (45.73% ± 1.13) and umami amino acids (1422.77 mg/100 g ± 119.87), as well as the lowest chewiness (3346.89 ± 121.19). The ham with 5.5% salt also had higher sensory scores of texture (4.83 ± 0.1), taste (5.50 ± 0.2) and overall acceptance (5.51 ± 0.09) as compared to the ham added with other salt levels. These results indicated that 5.5% NaCl treatment showed positive effects on the texture and taste of dry-cured ham, which meets the consumer's demand for dry-cured meat products.

SUN-552 Follistatin-Like 3 (FSTL3), a Transforming Growth Factor β (TGFβ) Ligand Inhibitor, Regulates Placental Development in Mice

Follistatin-like 3 (FSTL3), a glycoprotein that inhibits transforming growth factor-β (TGFβ) ligands such as activin, is expressed highly in the placenta and other vascular tissues. In addition, FSTL3 is strongly induced in pre-eclamptic placenta. To test the hypothesis that FSTL3 function is required for capillary bed structure and function we studied the placenta in FSTL3 gene deleted mice (FSTL3 KO). We have previously shown that FSTL3 deletion produces striking defects in the placenta when compared to WT. Placental size increases significantly in comparison to WT, at 16.5 and 18.5 dpc, with concurrent reduction in placental efficiency at 18.5 dpc. Histological analyses reveal structural differences in placental junctional zones in FSTL3 KO placenta compared to WT. Morphometric analyses show that the labyrinth area compared to the placenta area is significantly reduced in FSTL3 KO mice. We also found that activin-responsive FSTL3-synexpression genes are upregulated in FSTL3 KO placenta. Of these, EPHB4 protein is induced in the placenta along with its ligand EphrinB2. Here we show that FSTL3 deletion leads to endothelial cell expansion but reduction in blood vessel density along with increased extracellular matrix deposition. Further investigation of the placental phenotype revealed differential expression patterns of desmin and cytokeratin protein, reduced von Willebrand factor (VWF) and increased CD31 and VEGFR2 labelling within FSTL3 KO mice placental labyrinths. To identify mechanisms that might lead to the altered placental development in FSTL3 KO mice qPCR analyses were performed. Our results identified differences in the expression of crucial transcripts, such as Cdh5, Pgf, Fra1and Cited1, that are associated with the regulation of vascular biology. Additionally, we find increased Histone3 and SMAD2 phosphorylation in FSTL3 KO placenta indicating increased proliferation and activin signalling, respectively. These findings suggest that the balance between cellular proliferation and differentiation might be altered in the absence of FSTL3. Thus, we conclude that FSTL3 function, at least partly through the inhibition of activin action, is necessary for normal placental circulation and development.

AAV-mediated cardiac gene transfer of wild-type desmin in mouse models for recessive desminopathies

Mutations in the human desmin gene cause autosomal-dominant and recessive cardiomyopathies and myopathies with marked phenotypic variability. Here, we investigated the effects of adeno-associated virus (AAV)-mediated cardiac wild-type desmin expression in homozygous desmin knockout (DKO) and homozygous R349P desmin knockin (DKI) mice. These mice serve as disease models for two subforms of autosomal-recessive desminopathies, the former for the one with a complete lack of desmin protein and the latter for the one with solely mutant desmin protein expression in conjunction with protein aggregation pathology in striated muscle. Two-month-old mice were injected with either a single dose of 5 × 1012 AAV9-hTNT2-mDes (AAV-Des) vector genomes or NaCl as control. One week after injection, mice were subjected to a forced swimming exercise protocol for 4 weeks. Cardiac function was monitored over a period of 15 month after injection and before the mice were sacrificed for biochemical and morphological analysis. AAV-mediated cardiac expression of wild-type desmin in both the homozygous DKO and DKI backgrounds reached levels seen in wild-type mice. Notably, AAV-Des treated DKO mice showed a regular subcellular distribution of desmin as well as a normalization of functional and morphological cardiac parameters. Treated DKI mice, however, showed an aberrant subcellular localization of desmin, unchanged functional cardiac parameters, and a trend toward an increased cardiac fibrosis. In conclusion, the effect of a high-dose AAV9-based desmin gene therapy is highly beneficial for the heart in DKO animals, but not in DKI mice.

Aldehyde dehydrogenase 2 regulates autophagy via the Akt-mTOR pathway to mitigate renal ischemia-reperfusion injury in hypothermic machine perfusion

AimsIschemia-reperfusion injury (IRI) is harmful to patients following kidney transplantation. Hypothermic machine perfusion (HMP) can be adopted to preserve grafts and reduce consequential injury. We hypothesized that aldehyde dehydrogenase 2 (ALDH2) partly mitigates kidney IRI via regulating excessive autophagy in HMP. Materials and methodsThe rabbits were assigned to 5 groups: Normal, HMP, HMP + Alda-1, HMP + CYA and cold storage (CS). After the rabbit autologous kidney transplantation, renal pathology and function were evaluated by histological analysis, glomerular related proteins (desmin, nephrin), tubular injury factors (NGAL, Ki67), serum creatinine (Cr) and blood urea nitrogen (BUN). Oxidative stress molecular Malondialdehyde (MDA) and superoxide dismutase (SOD2) expression, as well as inflammatory cytokines (TNF-α, IL-6, IL-10) were assessed by immunohistochemistry. The expression of LC3, p62, ALDH2, p-Akt, mTOR, PTEN, p-PTEN, and 4-HNE were measured by immunohistochemistry, RT-PCR, Western blot analysis or ELISA. Key findingsHMP was more effective than CS for kidney preservation, with p- ALDH2 expressed in greater quantities in HMP. The results of kidney pathology and function in HMP + Alda-1 were the best. The MDA & SOD2 and the Vyacheslav score were improved in HMP + CYA. ALDH2 reduced 4-HNE-induced oxidative stress, inflammatory infiltration, the expression of LC3, p62 and inhibited autophagy accompanied by activation of p-Akt and mTOR via p-PTEN/PTEN. SignificanceAkt-mTOR autophagy pathway is a novel target for ALDH2 to reduce renal IRI partly by inhibition of 4-HNE in HMP, then protecting the donated kidney received after cardiac death (DCD).

Complex Correlations Between Desmin Content, Myofiber Types, and Innervation Patterns in the Human Extraocular Muscles.

PurposeTo investigate whether the distribution of intermediate filament protein desmin is related to the different patterns of innervation in the human extraocular muscles (EOMs).MethodsEOM samples were analyzed with immunohistochemistry using antibodies against desmin, vimentin, different myosin heavy chain (MyHC) isoforms, and fetal and adult acetylcholine receptor (AChR) subunits. Neuromuscular junctions (NMJs) were identified with α-bungarotoxin or with antibodies against neurofilament and synaptophysin.ResultsDesmin was present in the vast majority of myofibers, but it was weakly present or absent in a limited area in the close vicinity of the single en plaque NMJs in less than half of these myofibers. Desmin was either present or lacking in MyHCsto/I myofibers displaying multiple en grappe endings but present in MyHCsto/I myofibers receiving spiral nerve endings. In MyHCeom myofibers displaying multiterminal en plaque endings, desmin was either present or absent irrespective of AChR subunits or EOM layer. Vimentin did not substitute for the lack of desmin.ConclusionsThe results indicate that the human EOMs have a more complex cytoskeletal organization than other muscles and suggest additional signalling mechanisms from the NMJs to the myofibers.

Expanding the differential of cutaneous epithelioid tumors: A case of dedifferentiated liposarcoma with epithelioid features involving the skin, with review of the literature

Liposarcomas are categorized into four distinct histopathological subtypes: atypical lipomatous tumors (ALT)/well-differentiated liposarcoma (WDL), dedifferentiated, myxoid, and pleomorphic. Dedifferentiated liposarcomas account for approximately 18% of all liposarcomas, characteristically arising in the deep soft tissue. They are reported to have lower rates of metastasis compared to other pleomorphic sarcomas.1 -3 The classic histopathologic appearance is ALT/WDL admixed or juxtaposed with a predominantly nonlipogenic sarcoma. Epithelioid features are rare, appearing in as few as 3% of tumors, and have not previously been reported in a superficial location. Herein, we present a 57-year-old male with intradermal and subcutaneous metastasis of his known deep dedifferentiated liposarcoma with epithelioid features. By H&E the tumor featured cords and sheets of crowded, plump, epithelioid cells with thick nuclear membranes and prominent nucleoli, which raised a broad differential including carcinoma and melanoma. By immunohistochemistry the tumor was diffusely positive for MDM2 and CDK4, on the other hand stains for Sox10, Melan A, MITF, CKAE1/3, desmin, and S100 protein were negative. This case serves as an opportunity to raise awareness of this rare morphological subtype, which can involve the skin and mimic epithelial and melanocytic malignancies. It can be a potential diagnostic pitfall, especially if metastases are the first presentation.

PDGFRα and αSMA mark two distinct mesenchymal cell populations involved in parenchymal and vascular remodeling in pulmonary fibrosis.

Pulmonary fibrosis is characterized by pronounced collagen deposition and myofibroblast expansion, whose origin and plasticity remain elusive. We utilized a fate-mapping approach to investigate α-smooth muscle actin (αSMA)+ and platelet-derived growth factor receptor α (PDGFRα)+ cells in two lung fibrosis models, complemented by cell type-specific next-generation sequencing and investigations on human lungs. Our data revealed that αSMA+ and PDGFRα+ cells mark two distinct mesenchymal lineages with minimal transdifferentiation potential during lung fibrotic remodeling. Parenchymal and perivascular fibrotic regions were populated predominantly with PDGFRα+ cells expressing collagen, while αSMA+ cells in the parenchyma and vessel wall showed variable expression of collagen and the contractile protein desmin. The distinct gene expression profile found in normal conditions was retained during pathologic remodeling. Cumulatively, our findings identify αSMA+ and PDGFRα+ cells as two separate lineages with distinct gene expression profiles in adult lungs. This cellular heterogeneity suggests that anti-fibrotic therapy should target diverse cell populations.

Accelerated Muscle Recovery After In Vivo Curcumin Supplementation

The currently available treatment options for muscle injuries are suboptimal and often delay muscle recovery. In this study, the effects of curcumin on inflammation and skeletal muscle regeneration after contusion-induced injury in mice were investigated. The mice were randomly assigned to 4 groups, namely normal control (NC), with induced injury (mass-drop injury, MDI) and without treatment (MDI [M]), with induced injury and diclofenac (DCF) treatment (MDI + DCF [M + D]), and with induced injury and curcumin treatment (MDI + curcumin [M + C]). Contusion-induced injury was inflicted on the left gastrocnemius muscle, and DCF or curcumin was orally administered after injury once per day for 7 days. The M group exhibited significantly higher lipid peroxidation, myeloperoxidase (MPO), and desmin than the NC group. The M + D and M + C groups have lower lipid peroxidation and neutrophils (decrease in MPO protein) and higher muscle satellite cell regeneration (increase in desmin protein) than the M group. Additionally, for the contusion-induced muscle injury, curcumin could affect the specific proteins of inflammation, neutrophils, and differentiation of satellite cells, including Ikk-α/ß, MPO, and myogenin. In conclusion, curcumin potentially accelerates muscle recovery; therefore, it may be a potential candidate for further research as an effective treatment to enhance muscle repair.

Protective Effects of Resveratrol Supplementation on Contusion Induced Muscle Injury.

Muscle injuries frequently occur in contact sports events. The current treatment options for soft tissue injuries remain suboptimal and often result in delayed or incomplete recovery of damaged muscles. Resveratrol (RES) is a phenolic phytochemical, well-known for its antioxidant and anti-inflammatory properties. The purpose of this study is to evaluate the potential beneficial effects of RES supplementation on inflammation and regeneration in skeletal muscle after a contusion injury, in comparison to a conventional treatment of nonsteroidal anti-inflammatory drugs (NSAID). After one week of acclimation, forty eight -week-old male ICR mice were randomly divided into the five groups (n=8 per group): 1) normal control (NC), 2) mass-drop injury without any treatment (mass-drop injury, MDI), 3) post-injury NSAID treatment (MDI+ 10mg/kg NSAID), 4) post-injury RES supplementation (MDI+ 25mg/kg/day RES) and 5) post-injury treatment with RES and NSAID (MDI + resveratrol+ NSAID). After muscle contusion injury of the left gastrocnemius muscle, RES or NSAID were orally administered post-injury once a day for 7 days. Results showed that the MDI group had significantly higher serum uric acid (UA), CREA (creatinine), LDH (lactic dehydrogenase) and creatine kinase (CK) than the normal control group. Treatment with resveratrol reduced muscle damage as evidenced by the significantly decreased serum levels of UA, CREA, LDH and CK after contusion-induced muscle injuries in mice. In addition, RES and RES + NSAID groups promoted muscle satellite cell regeneration with increase in desmin protein after injury. Our results suggest that resveratrol combined with NSAID potentially improve muscle recovery and may be a potential candidate for further development as an effective clinical treatment for muscle repair.

Leg myxoid liposarcoma: correlation between image and anatomopathological tests

ABSTRACT A 41-year-old male patient refers to a painful tumor on the lateral side of the right leg. Ultrasonography visualized a predominantly hypoechoic well-delineated large heterogeneous mass in the subcutaneous tissue, showing an internal hyperechoic area. Magnetic resonance imaging (MRI) demonstrated an oval and lobulated tumor with well-defined margins at the anterolateral part of the leg, with contrast enhancement. The anatomopathological evaluation revealed a neoplasm with an extensive chondromyxoid matrix. The immunohistochemical study demonstrated positive vimentin (V9 clone), positive S-100 protein and negative desmin (D33 clone), smooth muscle actin (1A4), CD68 (KP1 clone) and caldesmon. The set of findings is compatible with myxoid liposarcoma.

Epigenetic downregulation of desmin in gall bladder cancer reveals its potential role in disease progression

Background & objectives:Gall bladder cancer (GBC) is a fatal neoplasm, with a globally variable incidence rates. To improve the survival rate of patients, a newer set of biomarkers needs to be discovered for its early detection and better prognosis. Our earlier studies on GBC proteomics and whole-genome methylome data revealed expression of desmin to be significantly downregulated with correlated promoter hypermethylation during gall bladder carcinogenesis. Thus, to evaluate desmin as a potential biomarker for GBC, we carried out a detailed follow up study.Methods:Methylation-specific polymerase chain reaction (MS-PCR) (n=17, GBC and n=23, non-tumour control), real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) [n=14, GBC and n=14, adjacent non-tumour (ANT)], immunohistochemistry (n=27, GBC and n=14, non-tumour) and immunoblotting (n=13, GBC and n=13, ANT) were performed in surgically removed gall bladder tissue samples.Results:MS-PCR analysis showed methylation of desmin in 88.23 per cent (15/17) gall bladder tumour samples as compared to non-tumour tissues (39.13%, 9/23). Real-time qRT-PCR analysis revealed a significant downregulation of desmin expression in GBC as compared to ANT tissue. This was further confirmed by western blot, showing reduced expression of desmin protein in GBC, as compared to non-tumour tissue. Immunohistochemical analysis also showed a decreased level of desmin i.e., more than 95 per cent (26/27) in tumour cells compared to non-tumours (35.71%, 5/14).Interpretation & conclusions:The increased frequency of desmin promoter methylation which could be responsible for its significant downregulation, indicates its potential as a candidate biomarker for GBC. This requires further validation in a large group of patients to evaluate its clinical utility.

Follistatin Mitigates Myofibroblast Differentiation and Collagen Synthesis of Fibroblasts from Scar Tissue around Injured Flexor Tendons.

PurposeThe aim of this study was to investigate the effect of FST gene on the inhibition of fibrosis in fibroblastic cells from scar tissue around repaired zone II flexor tendons.Materials and MethodsImmunohistochemistry was conducted on fibroblast cells transfected with adenovirus-LacZ (Ad-LacZ) as a marker gene (control), or with adenovirus-FST (Ad-FST) as a therapeutic gene. Fibroblast cultures without adenoviral exposure served as controls.ResultsFibroblastic cells transfected with Ad-FST demonstrated significant decrease in collagen type I, MMP-1, MMP2, and α-SMA mRNA expressions compared to those transfected with Ad-LacZ. In addition, fibroblastic cells transfected with Ad-FST exhibited significant decrease in MMP-1, TIMP-1, fibronectin, PAI-1, TRPV4, α-SMA, desmin, and PAX7 protein expressions.ConclusionBased on these findings, we conclude that FST may be a novel therapeutic strategy for preventing scar adhesions around repaired tendons by inhibiting fibroblasts from differentiating into myofibroblasts, in addition to producing type I collagen and regulating extracellular matrix turnover via the downregulation of MMP-1 and TIMP-1. FST may also decrease contracture of the scar by inhibiting Ca2+-dependent cell contraction.

Cardiomyopathies associated with the DES gene mutations: molecular pathogenesis and gene therapy approaches

Cardiomyopathy (CMP) is a common group of cardiovascular disorders. Genetic (primary) cardiomyopathies are related to abnormalities in more than 100 genes, including the DES gene encoding desmin protein. Desmin is an essential member of the intermediate filaments, ensuring the structural and functional integrity of myocytes. Mutations in the DES gene result in desmin-related cardiomyopathy with progressive course and poor prognosis. By now, specific therapy for cardiomyopathy has not been developed. Existing conservative and surgical treatment modalities target the rate of heart failure progression and sudden cardiac death prevention but have limited efficacy. The development of gene therapy and genome editing could allow for creating effective and specific methods of gene-based therapy for desminopathies. A number of studies have been published on the use of gene therapy for various genetic cardiomyopathies including those caused by the DES gene mutations, while genome editing has not been used yet. However, promising results have been obtained with CRISPR/Cas9 and TALEN editing systems to correct for “gain-of-function mutations” in some other genes, such as MYBPC3 and PLN. There is also evidence of the possibility to reduce the symptoms of desmin-related cardiomyopathy up to the normal function by knocking out the mutant DES allele, and preserved protein function provided by expression of the normal allele. We believe that genome editing approaches have an open perspective into the development of specific and effective methods to treat desminopathies.

Increased expression of desmin and vimentin reduces bladder smooth muscle contractility via JNK2.

Bladder dysfunction is associated with the overexpression of the intermediate filament (IF) proteins desmin and vimentin in obstructed bladder smooth muscle (BSM). However, the mechanisms by which these proteins contribute to BSM dysfunction are not known. Previous studies have shown that desmin and vimentin directly participate in signal transduction. In this study, we hypothesized that BSM dysfunction associated with overexpression of desmin or vimentin is mediated via c-Jun N-terminal kinase (JNK). We employed a model of murine BSM tissue in which increased expression of desmin or vimentin was induced by adenoviral transduction to examine the sufficiency of increased IF protein expression to reduce BSM contraction. Murine BSM strips overexpressing desmin or vimentin generated less force in response to KCl and carbachol relative to the levels in control murine BSM strips, an effect associated with increased JNK2 phosphorylation and reduced myosin light chain (MLC20 ) phosphorylation. Furthermore, desmin and vimentin overexpressions did not alter BSM contractility and MLC20 phosphorylation in strips isolated from JNK2 knockout mice. Pharmacological JNK2 inhibition produced results qualitatively similar to those caused by JNK2 knockout. These findings suggest that inhibition of JNK2 may improve diminished BSM contractility associated with obstructive bladder disease.

A Novel DES L115F Mutation Identified by Whole Exome Sequencing is Associated with Inherited Cardiac Conduction Disease.

Inherited cardiac conduction disease (CCD) is rare; it is caused by a large number of mutations in genes encoding cardiac ion channels and cytoskeletal proteins. Recently, whole-exome sequencing has been successfully used to identify causal mutations for rare monogenic Mendelian diseases. We used trio-based whole-exome sequencing to study a Chinese family with multiple family members affected by CCD, and identified a heterozygous missense mutation (c.343C>T, p.Leu115Phe) in the desmin (DES) gene as the most likely candidate causal mutation for the development of CCD in this family. The mutation is novel and is predicted to affect the conformation of the coiled-coil rod domain of DES according to structural model prediction. Its pathogenicity in desmin protein aggregation was further confirmed by expressing the mutation, both in a cellular model and a CRISPR/CAS9 knock-in mouse model. In conclusion, our results suggest that whole-exome sequencing is a feasible approach to identify candidate genes underlying inherited conduction diseases.

Identification of the intermediate filament protein synemin/SYNM as a target of myocardin family coactivators.

Myocardin (MYOCD) is a critical regulator of smooth muscle cell (SMC) differentiation, but its transcriptional targets remain to be exhaustively characterized, especially at the protein level. Here we leveraged human RNA and protein expression data to identify novel potential MYOCD targets. Using correlation analyses we found several targets that we could confirm at the protein level, including SORBS1, SLMAP, SYNM, and MCAM. We focused on SYNM, which encodes the intermediate filament protein synemin. SYNM rivalled smooth muscle myosin (MYH11) for SMC specificity and was controlled at the mRNA and protein levels by all myocardin-related transcription factors (MRTFs: MYOCD, MRTF-A/MKL1, and MRTF-B/MKL2). MRTF activity is regulated by the ratio of filamentous to globular actin, and SYNM was accordingly reduced by interventions that depolymerize actin, such as latrunculin treatment and overexpression of constitutively active cofilin. Many MRTF target genes depend on serum response factor (SRF), but SYNM lacked SRF-binding motifs in its proximal promoter, which was not directly regulated by MYOCD. Furthermore, SYNM resisted SRF silencing, yet the time course of induction closely paralleled that of the SRF-dependent target gene ACTA2. SYNM was repressed by the ternary complex factor (TCF) FLI1 and was increased in mouse embryonic fibroblasts lacking three classical TCFs (ELK1, ELK3, and ELK4). Imaging showed colocalization of SYNM with the intermediate filament proteins desmin and vimentin, and MRTF-A/MKL1 increased SYNM-containing intermediate filaments in SMCs. These studies identify SYNM as a novel SRF-independent target of myocardin that is abundantly expressed in all SMCs.

Expression patterns of intermediate filament proteins desmin and lamin A in the developing conduction system of early human embryonic hearts.

Since embryonic heart development is a complex process and acquisition of human embryonic specimens is challenging, the mechanism by which the embryonic conduction system develops remains unclear. Herein, we attempt to gain insights into this developmental process through immunohistochemical staining and 3D reconstructions. Expression analysis of T-box transcription factor 3, cytoskeleton desmin, and nucleoskeleton lamin A protein in human embryos in Carnegie stages 11-20 showed that desmin is preferentially expressed in the myocardium of the central conduction system compared with the peripheral conduction system, and is co-expressed with T-box transcription factor 3 in the central conduction system. Further, lamin A was first expressed in the embryonic ventricular trabeculations, where the terminal ramifications of the peripheral conduction system develop, and extended progressively to all parts of the central conduction system. The uncoupled spatiotemporal distribution pattern of lamin A and desmin indicated that the association of cytoskeleton desmin and nucleoskeleton lamin A may be a late event in human embryonic heart development. Compared with model animals, our data provide a direct morphological basis for understanding the arrhythmogenesis caused by mutations in human DES and LMNA genes.

First Case Report of Primary Testicular Diffuse Large B-Cell Lymphoma from the Western Region of Saudi Arabia

Primary testicular lymphoma (PTL) represents 1-2% of all types of non-Hodgkin lymphomas (NHLs) and 1-10% of testicular neoplasms. Up to the best of my knowledge, this is the first case of PTL of the diffuse large B-cell lymphoma (DLBCL) in a 60-year-old man presented with a painless mass in the left testis as revealed by physical examination in a tertiary care hospital in Al-Madinah Al-Munwarah in the western region of the Kingdom of Saudi Arabia (KSA). Radiological examination revealed a large well-defined heterogeneous predominantly hypo-echoic mass with increased vascularity in the upper portion of the testis. On the other hand, histopathological examination revealed a tumor involving the whole left testis, which was large (measuring 6 3.5 3.3 cm), solid and dark red with focal areas of hemorrhage and epididymal infiltration. Immunohistochemistry showed positivity of leucocyte common antigen (LCA), pan B-cell marker (CD20) and negativity of pan T-cell marker (CD3). Other immunohistochemical markers such as CD10, placental alkaline phosphatase (PLAP), cytokeratin, vimentin, desmin and S100 protein were also negative. However, there was a marked expression of Ki67 and Bcl2 markers. Accordingly, the diagnosis of DLBCL was established. The tumor was classified as stage I according to the Ann Arbor system. The case was treated by orchiectomy followed by prophylactic anthracycline-based chemotherapy and irradiation of the contralateral testis and central nervous system.

P.80Imbalances in protein homeostasis caused by mutant desmin

Mutations of the human desmin gene cause myopathies and cardiomyopathies. We investigated immortalized R349P desmin knock-in myoblasts and myotubes in conjunction with the corresponding desminopathy mice as models for desminopathies to analyse major protein quality control processes in response to the presence of R349P mutant desmin. Desmin immunoblots and immunostains of differentiated myotubes revealed that these desminopathy cell models closely mirror central aspects of the desmin pathology observed in our desminopathy mice. Proteasomal activity was increased in muscle tissue lysates derived from hetero- and homozygous R349P desmin knock-in mice. Notably, treatment of the desminopathy myoblasts with the proteasome inhibitor MG132 did not alter the levels of both wild-type and R349P mutant desmin protein. Immunoblotting of tissue and myotube lysates demonstrated markedly increased levels of the autophagy-related markers serin/threonin protein kinase Ulk-1 and sequestosome 1 (p62/SQSTM1) as well as of p62/SQSTM1 and LC3-II. Furthermore, we detected increased protein levels of filamin-C and BAG-3. Finally, we found increased protein levels of αB-crystallin, Hsp27, and Hsp90 in skeletal muscle homogenates from homozygous mice, while only αB-crystallin and Hsp27, but not Hsp90, were increased in both desminopathy myotube genotypes. Both αB-crystallin and Hsp27 as well as Hsp90 displayed translocation patterns from Z-discs as well as Z-I junctions, respectively, to the level of sarcomeric I-bands. Our findings demonstrate that the presence of R349P mutant desmin causes a general imbalance in skeletal muscle protein homeostasis via aberrant activity of all major protein quality control systems. The augmented activity of these systems and the subcellular shift of essential heat shock proteins may deleteriously contribute to the previously observed increased turnover of desmin itself and desmin-binding partners, which triggers progressive dysfunction of the extrasarcomeric cytoskeleton and the myofibrillar apparatus in the course of the development of desminopathies.