EULAR recommendations for the management and vaccination of people with rheumatic and musculoskeletal diseases in the context of SARS-CoV-2: the November 2021 update.

The first EULAR provisional recommendations on the management of rheumatic and musculoskeletal diseases (RMDs) in the context of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), largely based on expert opinion, were published in June 2020. Since then, an unprecedented number of clinical studies have accrued in the literature. Several SARS-CoV-2 vaccines have been approved for population-wide vaccination programmes in EULAR-affiliated countries. Studies regarding vaccination of patients with (inflammatory) RMDs have released their first results or are underway.EULAR found it opportune to carefully review to what extent the initially consensus expert recommendations stood the test of time, by challenging them with the recently accumulated body of scientific evidence, and by incorporating evidence-based advice on SARS-CoV-2 vaccination. EULAR started a formal (first) update in January 2021, performed a systematic literature review according to EULAR's standard operating procedures and completed a set of updated overarching principles and recommendations in July 2021. Two points to consider were added in November 2021, because of recent developments pertaining to additional vaccination doses.

Beyond the physico-chemical barrier: Glycerol and xylitol markedly yet differentially alter gene expression profiles and modify signalling pathways in human epidermal keratinocytes.

Polyols (e.g. glycerol, xylitol) are implicated as moisturizers of the skin and other epithelial tissues. However, we lack information about their exact cellular mechanisms and their effects on the gene expression profiles. Therefore, in this study, we aimed at investigating the effects of glycerol and xylitol on human epidermal keratinocytes. The polyols (identical osmolarities; xylitol: 0.0045%-0.45%; glycerol: 0.0027%-0.27%) did not alter cellular viability or intracellular calcium concentration. However, they exerted differential effects on the expression of certain genes and signalling pathways. Indeed, both polyols up-regulated the expression of filaggrin, loricrin, involucrin and occludin; yet, xylitol exerted somewhat more profound effects. Moreover, while both polyols stimulated the MAPK pathway, only xylitol induced the activation-dependent translocation of protein kinase Cδ, a key promoter of epidermal differentiation. Finally, in various keratinocyte inflammation models, both polyols (albeit with different efficacies) exerted anti-inflammatory effects. Taken together, these data strongly suggest that glycerol and xylitol differentially modulate expressions of multiple genes and activities of signalling pathways in epidermal keratinocytes. Thus, our findings invite clinical trials to explore the applicability and the impact of a combined glycerol-xylitol therapy in the management of various skin conditions.

Micronucleus formation during chromatin condensation and under apoptotic conditions.

In early S phase the newly replicated DNA is folded back to increasingly compact structures. The process of chromatin condensation inside the nucleus starts with the formation of a micronucleus observed in five established cell lines (K562, CHO, Indian muntjac, murine preB and SCC). Supercoiling of chromatin generates a polarized end-plate region extruded from the nucleus. The extruded chromatin is turned around itself forming the head portion (micronucleus) visible by fluorescence microscopy until the middle of S phase when chromatin structures are succeeded by distinguishable early forms of chromosomes. The generation of micronuclei upon apoptotic treatment was achieved by the methotrexate (MTX) treatment of cells. A close correlation was found between the frequency of micronucleus and MTX concentration, with low frequency at low (0.1 µM) and increasingly higher frequency between 1 and 100 µM concentrations. Characteristic deformation and shrinkage of nuclei indicated apoptosis. High MTX concentration (100 µM) caused the enlargement and necrotic disruption of nuclei. Inhibition of DNA synthesis during replicative DNA synthesis by biotinylated nucleotide prevented the formation of metaphase chromosomes and elevated the frequency of early intermediates of chromosome condensation including micronucleus formation. Based on these observations the micronucleus is regarded as: (a) a regularly occuring element of early chromatin condensation and (b) a typical sign of nuclear membrane damage under toxic conditions. Explanation is given why the micronucleus is hidden in nuclei under normal chromatin condensation and why chromatin motifs including micronuclei become visible upon cellular damage.

PRMT1 and PRMT8 regulate retinoic acid-dependent neuronal differentiation with implications to neuropathology.

Retinoids are morphogens and have been implicated in cell fate commitment of embryonic stem cells (ESCs) to neurons. Their effects are mediated by RAR and RXR nuclear receptors. However, transcriptional cofactors required for cell and gene-specific retinoid signaling are not known. Here we show that protein arginine methyl transferase (PRMT) 1 and 8 have key roles in determining retinoid regulated gene expression and cellular specification in a multistage neuronal differentiation model of murine ESCs. PRMT1 acts as a selective modulator, providing the cells with a mechanism to reduce the potency of retinoid signals on regulatory "hotspots." PRMT8 is a retinoid receptor target gene itself and acts as a cell type specific transcriptional coactivator of retinoid signaling at later stages of differentiation. Lack of either of them leads to reduced nuclear arginine methylation, dysregulated neuronal gene expression, and altered neuronal activity. Importantly, depletion of PRMT8 results in altered expression of a distinct set of genes, including markers of gliomagenesis. PRMT8 is almost entirely absent in human glioblastoma tissues. We propose that PRMT1 and PRMT8 serve as a rheostat of retinoid signaling to determine neuronal cell specification in a context-dependent manner and might also be relevant in the development of human brain malignancy.

Protein kinase Cδ promotes proliferation and induces malignant transformation in skeletal muscle.

In this paper, we investigated the isoform-specific roles of certain protein kinase C (PKC) isoforms in the regulation of skeletal muscle growth. Here, we provide the first intriguing functional evidence that nPKCδ (originally described as an inhibitor of proliferation in various cells types) is a key player in promoting both in vitro and in vivo skeletal muscle growth. Recombinant overexpression of a constitutively active nPKCδ in C2C12 myoblast increased proliferation and inhibited differentiation. Conversely, overexpression of kinase-negative mutant of nPKCδ (DN-nPKCδ) markedly inhibited cell growth. Moreover, overexpression of nPKCδ also stimulated in vivo tumour growth and induced malignant transformation in immunodeficient (SCID) mice whereas that of DN-nPKCδ suppressed tumour formation. The role of nPKCδ in the formation of rhabdomyosarcoma was also investigated where recombinant overexpression of nPKCδ in human rhabdomyosarcoma RD cells also increased cell proliferation and enhanced tumour formation in mouse xenografts. The other isoforms investigated (PKCα, ß, ε) exerted only minor (mostly growth-inhibitory) effects in skeletal muscle cells. Collectively, our data introduce nPKCδ as a novel growth-promoting molecule in skeletal muscles and invite further trials to exploit its therapeutic potential in the treatment of skeletal muscle malignancies.

Excessive pediatric fasciitis necrotisans due to Pseudomonas aeruginosa infection successfully treated with negative pressure wound therapy.

The case of a 10-year old female child is described with a history of myeloproliferative disorder having skin, bone and visceral involvement. Bone marrow biopsy revealed histiocytosis X. During chemotherapy necrotizing fasciitis of the lower abdominal wall was diagnosed. Multiple microbiological cultures taken from the wound base revealed Pseudomonas aeruginosa infection. Surgical necrectomy and application of negative pressure wound therapy (NPWT) was started together with intensive care treatment for sepsis. As both wound and general condition of the patient improved, autologous split thickness skin grafting was carried out in two sitting under continuing NPWT application. The applied skin grafts showed excellent take, the perilesional subcutaneous recesses resolved and complete healing was achieved after 28 days of NPWT treatment. Proper dermatological diagnosis and immediate escharectomy complemented with application of NPWT can be life-saving in the treatment of necrotizing fasciitis.

Function of RasGRP3 in the formation and progression of human breast cancer.

INTRODUCTION: Ras guanine nucleotide exchange factors (RasGEFs) mediate the activation of the Ras signaling pathway that is over activated in many human cancers. The RasGRP3, an activator of H-Ras and R-Ras protein exerts oncogenic effects and the overexpression of the protein is observed in numerous malignant cancer types. Here, we investigated the putative alteration of expression and potential function of RasGRP3 in the formation and progression of human breast cancer. METHODS: The RasGRP3 and phosphoRasGRP3 expressions were examined in human invasive ductal adenocarcinoma derived samples and cell lines (BT-474, JIMT-1, MCF7, SK-BR-3, MDA-MB-453, T-47D) both in mRNA (Q-PCR) and protein (Western blot; immunohistochemistry) levels. To explore the biological function of the protein, RasGRP3 knockdown cultures were established. To assess the role of RasGRP3 in the viability of cells, annexin-V/PI staining and MitoProbe™ DilC1 (5) assay were performed. To clarify the function of the protein in cell proliferation and in the development of chemotherapeutic resistance, CyQuant assay was performed. To observe the RasGRP3 function in tumor formation, the Severe combined immunodeficiency (SCID) mouse model was used. To investigate the role of the protein in Ras-related signaling Q-PCR and Western blot experiments were performed. RESULTS: RasGRP3 expression was elevated in human breast tumor tissue samples as well as in multiple human breast cancer cell lines. Down-regulation of RasGRP3 expression in breast cancer cells decreased cell proliferation, induced apoptosis in MCF7 cells, and sensitized T-47D cells to the action of drugs Tamoxifen and trastuzumab (Herceptin). Gene silencing of RasGRP3 reduced tumor formation in mouse xenografts as well. Inhibition of RasGRP3 expression also reduced Akt, ERK1/2 and estrogen receptor alpha phosphorylation downstream from IGF-I insulin like growth factor-I (IGF-I) or epidermal growth factor (EGF) stimulation confirming the functional role of RasGRP3 in the altered behavior of these cells. CONCLUSIONS: Taken together, our results suggest that the Ras activator RasGRP3 may have a role in the pathological behavior of breast cancer cells and may constitute a therapeutic target for human breast cancer.

Perceptions of parental involvement in youth handball players, the effects of sport participation stage and sports injury.

Introduction: Globally, from the age of 14, the dropout rate of young athletes is high in all sports games in Hungary. The reasons for dropping out are complex, however parental support is critical to succeed or continue, especially after failure or injury. The present study explored the main effects of sports injury and sport participation stage on parental involvement in sports. Methods: 1,174 parents and 690 athletes completed our questionnaire, which contains questions on young players' sport participation, injury background and Parental Involvement in Sport Questionnaire. Results: Parents' self-perceived level of involvement differed from the parental involvement perceived by their children. The significant predictors were the person who completed, the parent/athlete, the athlete's previous sports injury and the child's current stage of sport participation. In Directive Behavior, the main effect of stages is only seen in parents whose child has been injured. In the sample of injured athletes, the rate of perceived parental Praise and Understanding tends to be lower in the specializing stage. Discussion: Our findings suggest that these two behaviors could be part of the same parenting style, which requires further investigation. The results expand the existing knowledge of the complexity of parents' involvement in children's sports careers. These findings have implications beyond parental psychoeducation impacting the work of coaches, sports physicians and rehabilitation experts.

In vitro and in vivo activity of 4-thio-uridylate against JY cells, a model for human acute lymphoid leukemia.

We have previously reported the in vitro anti-proliferative effect of 4-thio-uridylate (s(4)UMP) on OCM-1 uveal melanoma cells. Here, we assessed the efficacy of s(4)UMP on JY cells. Treatment of JY cells with s(4)UMP suppressed their colony forming activity and induced apoptosis; healthy human bone marrow granulocyte-macrophage progenitor cells were 14-fold less sensitive to the nucleotide. In vivo effectiveness of s(4)UMP was determined using xenograft SCID mouse model. s(4)UMP decreased the cell number and colony forming activity of the total cell content of the femur of SCID mice transplanted with JY cells without affecting the bone marrow of healthy mice. These results suggest that s(4)UMP alone or in combination with other clinically approved anti-leukemic remedies should be further explored as a potential novel therapeutic agent.

Talent Selection Based on Sport-Specific Tasks Is Affected by the Relative Age Effects among Adolescent Handball Players.

Talent selection is often affected by the relative age effects (RAEs), resulting in the overrepresentation of relatively older (vs. relatively younger) players among those selected. The use of sport-specific tasks is suggested to reduce RAEs during talent selection. PURPOSE: To test the hypothesis that talent selection including only sport-specific tasks is not affected by the RAEs and to analyse the body size and biological maturity of the top selection level according to relative age. METHODS: Participants were U14 female (n = 5428) and U15 (n = 4408) male handball players participating in four programs consisting of four selection levels (local, county, regional, and national) grouped in bi-annual age. Handball-specific generic skills, position-specific technical drills and in-game performance were the selection criteria evaluated by experts and coaches. Body dimensions were measured and bone age, as an indicator of maturity, was estimated. The relative age quartile distributions within the bi-annual cohorts were examined using Chi-square and Odds Ratios. RESULTS: In terms of all the registered players no RAEs were evident. However, the RAEs of moderate effect size were evident at the county level; χ2 = 53.2 (girls) and 66.4 (boys), OR = 2.5 and 3.3, respectively. The RAEs of a large effect size were found at the regional level; χ2 = 139.5 (girls) and 144.9 (boys), OR = 8.2 and 5.2, respectively. At national level, RAEs were still present, but with no further increase in the effect size. At the highest selection level, there were no differences in the anthropometric measures between the relatively older and younger players. CONCLUSION: The findings provide support to the hypothesis that the selection process exacerbates RAEs even when using only sport-specific selection criteria. The performance metrics in technical skills, but also coaching assessments are likely involved. In addition, an advanced maturity and/or an above-average body size increases the selection odds for relatively younger players.

Immunogenicity and safety of the BNT162b2 mRNA COVID-19 vaccine in healthcare workers / A BNT162b2 mRNS-Pfizer-BioNTech-védooltás hatásosságának és immunogenitásának monitorozása egészségügyben dolgozókon.

Összefoglaló. Bevezetés: A SARS-CoV-2 koronavírus okozta COVID-19 általános egészségügyi és gazdasági krízist idézett elo. Célkituzés: A megfigyeléses vizsgálat célja a BNT162b2 mRNS-Pfizer-BioNTech-vakcina hatásosságának, biztonságosságának és immunogenitásának igazolása a Budai Irgalmasrendi Kórház dolgozóin. Módszer: A vakcina adása után elemeztük a COVID-19-fertozés elofordulását, az oltások utáni reakciókat, valamint a "spike" (S-) protein és a nukleokapszid (N)-protein elleni ellenanyag szintjének változását. Eredmények: A felmérésben részt vevo 295 dolgozó közül az oltást megelozoen 36 dolgozó esett át COVID-19-fertozésen (COVID-19-pozitív csoport). A második oltás után a megfigyelési idoszak három hónapjában COVID-19-fertozés nem alakult ki a felmérésben részt vevo oltott dolgozók körében. Az oltási reakciók enyhék voltak. A COVID-19-pozitív csoportban az N-antitestek medián küszöbértékindexe az elso vakcina után 4 héttel mérve szignifikánsan magasabb volt (28,37), mint a COVID-19-negatív (0,085) csoportban (p<0,0001). Az elso vakcina után 4 héttel az S-antitestek medián értéke (8015 U/ml) a COVID-19-pozitív csoportban szignifikánsan magasabb volt (p<0,0001), mint a COVID-19-negatív csoportban (23,18 U/ml). A COVID-19-negatív csoport S-antitest-középértéke a második vakcina után szignifikáns (p<0,0001), mintegy 500×-os emelkedést mutatott (23,18 U/ml rol 1173 U/ml-re). Egy vakcina hatásosságát a fertozések terjedésének megakadályozása igazolja. Következtetések: A második vakcina utáni megfigyelési idoszakban új COVID-19-fertozés nem volt az oltott dolgozók körében. A fertozésen át nem esett COVID-19-negatív egyének esetén az S-antitest emelkedése mérsékelt az elso oltás után, míg a második oltás után lényegesen emelkedik. A COVID-19-fertozésen átesett egyének csoportjában már az elso vakcina is jelentos S-antitest-termelodést vált ki. Orv Hetil. 2021; 162(39): 1551-1557. INTRODUCTION: The coronavirus disease 2019 (COVID-19) pandemic caused global public health and economic crises. OBJECTIVE: The aim of this observation study was to estimate the effectiveness, safety and elicited immune response of the BNT162b2 mRNA Pfizer-BioNTech vaccine in healthcare workers of the Buda Hospital of the Hospitaller Order of St. John of God. METHOD: After vaccination, the infection rate, adverse events and the kinetics of anti-SARS-CoV-2 spike (S) protein and anti-SARS-CoV-2 nucleocapsid (N) protein antibodies were evaluated. RESULTS: Before vaccination, from the 295 healthcare workers 36 recovered from prior COVID-19 infection (COVID-19-positive group). After the second vaccination, there was no COVID-19 infection during the three-month follow-up period. The adverse events were mild. In the COVID-19-positive group, the median cut-off index of anti-N antibodies measured at 4 weeks after the first vaccination were significantly (p<0.0001) higher (28.37) than in the COVID-19-negative group (0.085). After the first vaccine, the median titer of anti-S antibodies was significantly higher (p<0.0001) in the COVID-19-positive group (8015 U/ml) compared to the COVID-19-negative group (23.18 U/ml). In the COVID-19-negative group, the median titer of anti-S antibodies increased significantly (p<0.0001) after the second vaccine (from 23.18 U/ml to 1173 U/ml), showing an increase of 500×. CONCLUSIONS: After the second vaccination, there was no COVID-19 infection during the follow-up. In the COVID-19-negative group, the anti-S antibody titer is moderate after the first vaccination and increases significantly after the second vaccine. In the COVID-19-positive group, the first vaccine induces significant anti-S antibody production. Orv Hetil. 2021; 162(39): 1551-1557.

Metastatic Spread from Abdominal Tumor Cells to Parathymic Lymph Nodes.

Metastatic studies on rats showed that after subrenal implantation of tumor cells under the capsule of the kidney or subhepatic implantation under Glisson's capsule of the liver generated primary tumors in these organs. It was assumed that tumor cells that escaped through the disrupted peripheral blood vessels of primary tumors entered the peritoneal cavity, crossed the diaphragm, and appeared in the thoracal, primarily in the parathymic lymph nodes. This explanation did not answer the question whether distant lymph nodes were reached via the blood stream from the primary tumor or through the thoracal lymphatic vessels. In this work, we investigated the metastatic pathway in C3H/HeJ mice, after direct intraperitoneal administration of murine SCC VII cells bypassing the hematogenic spread of tumor cells. The direct pathway was also mimicked by intraperitoneal injection of Pelican Ink colloidal particles, which appeared in the parathymic lymph nodes, similarly to the tumor cells that caused metastasis in the parathymic lymph nodes and in the thymic tissue. The murine peritoneal-parathymic lymph node route indicates a general mechanism of tumor progression from the abdominal effusion. This pathway starts with the growth of abdominal tumors, continues as thoracal metastasis in parathymic lymph nodes and may proceed as mammary lymph node metastasis.

Controlled release of methotrexate from functionalized silica-gelatin aerogel microparticles applied against tumor cell growth.

Methotrexate functionalized silica-gelatin hybrid aerogel (SGM) was synthesized by the sol-gel method and co-gelation. The drug methotrexate (MTX) is covalently linked to the collagen molecules of the hybrid aerogel backbone by amide-bond. The characteristic MTX content of the functionalized hybrid aerogel is ca. 6 wt% by the dry weight. The micronization of SGM aerogel in water yields cell sized (d = 10-20 µm) particles. The cytotoxicity of these microparticles against tumor cell lines (SCC VII and HL-60) is unprecedentedly high, it is approximately equivalent to that of an equal dose of free (dissolved) MTX, as proved by in vitro experiments. Thus, the activity of MTX is intact after aerogel functionalization, and the mass specific cytotoxicity of SGM is high enough for medical applications. Drug release studies verified that MTX cannot be liberated from this drug delivery system solely by chemical hydrolysis, however, collagenase enzymatic activity releases MTX from the functionalized hybrid aerogel. The cytotoxicity of SGM towards various cancerous and non-cancerous cell lines correlates with the collagenase activities of cells. Therefore, conjugation with the hybrid aerogel provides a controlled release system for the antineoplastic agent MTX. The morphology of the delivery vehicle was chosen to adapt the size of cancer cells; thus the metastatic pathways of the tumor cells can get flooded.

Activation of Notch1 signaling is required for beta-catenin-mediated human primary melanoma progression.

Notch is a highly conserved transmembrane receptor that determines cell fate. Notch signaling denotes cleavage of the Notch intracellular domain, its translocation to the nucleus, and subsequent activation of target gene transcription. Involvement of Notch signaling in several cancers is well known, but its role in melanoma remains poorly characterized. Here we show that the Notch1 pathway is activated in human melanoma. Blocking Notch signaling suppressed whereas constitutive activation of the Notch1 pathway enhanced primary melanoma cell growth both in vitro and in vivo yet had little effect on metastatic melanoma cells. Activation of Notch1 signaling enabled primary melanoma cells to gain metastatic capability. Furthermore, the oncogenic effect of Notch1 on primary melanoma cells was mediated by beta-catenin, which was upregulated following Notch1 activation. Inhibiting beta-catenin expression reversed Notch1-enhanced tumor growth and metastasis. Our data therefore suggest a beta-catenin-dependent, stage-specific role for Notch1 signaling in promoting the progression of primary melanoma.

Trastuzumab decreases the number of circulating and disseminated tumor cells despite trastuzumab resistance of the primary tumor.

We have recently shown that despite of the fact that the ErbB2-positive JIMT-1 human breast cancer cells intrinsically resistant to trastuzumab in vitro, trastuzumab inhibited the outgrowth of early phase JIMT-1 xenografts in SCID mice via antibody-dependent cellular cytotoxicity (ADCC). Here we show that trastuzumab significantly reduces the number of circulating and disseminated tumor cells (CTCs and DTCs) in this xenograft model system at a time when the primary tumor is already unresponsive to trastuzumab. This observation suggests that ErbB2 positive CTCs and DTCs might be sensitive to trastuzumab-mediated ADCC even if when the primary tumor is already non-responsive. Thus, trastuzumab treatment might also be beneficial in the case of patients with breast cancer that is already trastuzumab resistant.

Investigation of micronized titanium dioxide penetration in human skin xenografts and its effect on cellular functions of human skin-derived cells.

Titanium dioxide (TiO2) nanoparticles are ubiquitously used materials in everyday life (e.g. paints,household products and plastic goods). However, despite the wide array of common applications, their pathogenetic role was also suggested under certain conditions (e.g. pulmonary neoplasias and lung fibrosis). From a dermatological point of view, it is also of great importance that TiO2 also serves as a physical photoprotective agent in sunscreens and is widely used in various cosmetic products. However, the effect of TiO2 on human cutaneous functions is still unknown. Therefore, in the current study, we investigated the in vivo penetration of TiO2 via human skin transplanted to immunodeficient mice and,furthermore, we measured the in vitro effects of nanoparticles on various functional properties of numerous epidermal and dermal cells in culture. Hereby, using various nuclear microscopy methods, we provide the first evidence that TiO2nanoparticles in vivo do not penetrate through the intact epidermal barrier. However, we also report that TiO2, when exposed directly to cell cultures in vitro, exerts significant and cell-type dependent effects on such cellular functions as viability, proliferation, apoptosis and differentiation. Therefore, our novel findings will hopefully inspire one to systemically explore in future, clinically oriented trials whether there is indeed a risk from micronized TiO2-containing products on skin with an impaired stratum corneum barrier function.

Trastuzumab causes antibody-dependent cellular cytotoxicity-mediated growth inhibition of submacroscopic JIMT-1 breast cancer xenografts despite intrinsic drug resistance.

Trastuzumab is a recombinant antibody drug that is widely used for the treatment of breast cancer. Despite encouraging clinical results, some cancers are primarily resistant to trastuzumab, and a majority of those initially responding become resistant during prolonged treatment. The mechanisms of trastuzumab resistance have not been fully understood. We examined the role of antibody-dependent cellular cytotoxicity (ADCC) using JIMT-1 cells that are ErbB2 positive but intrinsically resistant to trastuzumab in vitro. Unexpectedly, in experiments mimicking adjuvant therapy of submacroscopic disease in vivo (JIMT-1 cells inoculated s.c. in severe combined immunodeficiency mice), trastuzumab was able to inhibit the outgrowth of macroscopically detectable xenograft tumors for up to 5-7 weeks. The effect is likely to be mediated via ADCC because trastuzumab-F(ab')(2) was ineffective in this model. Moreover, in vitro ADCC reaction of human leukocytes was equally strong against breast cancer cells intrinsically sensitive (SKBR-3) or resistant (JIMT-1) to trastuzumab or even against a subline of JIMT-1 that was established from xenograft tumors growing despite trastuzumab treatment. These results suggest that ADCC may be the predominant mechanism of trastuzumab action on submacroscopic tumor spread. Thus, measuring the ADCC activity of patient's leukocytes against the tumor cells may be a relevant predictor of clinical trastuzumab responsiveness in vivo.

Insulin-like growth factor-I-coupled mitogenic signaling in primary cultured human skeletal muscle cells and in C2C12 myoblasts. A central role of protein kinase Cdelta.

In this study, we have investigated the effects of insulin-like growth factor-I (IGF-I) on cellular responses of primary human skeletal muscle cells and mouse C2C12 myoblasts. In human muscle, IGF-I stimulated proliferation and fusion of the cells and the expression of the differentiation marker desmin. These effects were completely inhibited by Rottlerin, the inhibitor of the protein kinase C (PKC)delta, but were not affected by the inhibition of the mitogen-activated protein kinase (MAPK) or the phosphatidylinositide 3-kinase (PI-3K) pathways. Furthermore, IGF-I initiated the selective translocation of PKCdelta to the nucleus. In C2C12 myoblasts, the growth-promoting effects of IGF-I were abrogated by inhibition of PKCdelta, but not by the inhibition of the PI-3K system. However, in contrast to the human data, the MAPK inhibitor PD098059 partially (yet significantly) also inhibited the action of IGF-I and, furthermore, IGF-I induced phosphorylation of the MAPK Erk-1/2. In addition, overexpression of constitutively active form of PKCdelta in C2C12 cells fully mimicked, whereas overexpression of kinase inactive mutant of the isoform prevented the action of IGF-I. Finally, the inhibition of PKCdelta suspended the IGF-I-induced phosphorylation of Erk-1/2 and, moreover, the inhibition of the MAPK pathway partially (yet significantly) inhibited the accelerated growth of C2C12 cells overexpressing PKCdelta. Taken together, these results demonstrate a novel, central and exclusive involvement of PKCdelta in mediating the action of IGF-I on human skeletal muscle cells, with an additional yet PKCdelta-dependent contribution of the MAPK pathway on C2C12 myoblasts.

Sebaceous Gland-Rich Skin Is Characterized by TSLP Expression and Distinct Immune Surveillance Which Is Disturbed in Rosacea.

The microbial community exhibits remarkable diversity on topographically distinct skin regions, which may be accompanied by differences in skin immune characteristics. Our aim was to compare the immune milieu of healthy sebaceous gland-rich (SGR) and sebaceous gland-poor skin areas, and to analyze its changes in an inflammatory disease of SGR skin. For this purpose, immunohistochemical, immunocytochemical, and quantitative real-time PCR analyses of thymic stromal lymphopoietin (TSLP) and other cytokines, phenotypic immune cell markers and transcription factors were carried out in samples from sebaceous gland-poor, SGR skin and from papulopustular rosacea. TSLP mRNA and protein production was also studied in cultured keratinocytes. In SGR skin, higher TSLP expression, dendritic cell appearance without prominent activation, and T cell presence with IL-17/IL-10 cytokine milieu were detected compared with sebaceous gland-poor skin. Linoleic acid, a major sebum component, was found to induce TSLP expression dose-dependently in keratinocytes. In papulopustular rosacea, significantly decreased TSLP level and influx of inflammatory dendritic cells and T cells with IL-17/interferon-γ cytokine milieu were observed. According to our results, SGR skin is characterized by a distinct, noninflammatory immune surveillance, which may explain the preferred localization of inflammatory skin diseases, and can influence future barrier repair therapeutic concepts.