Chemokine-like Receptor 1 in Brain of Spontaneously Hypertensive Rats Mediates Systemic Hypertension

Adipocytokine chemerin is a biologically active molecule secreted from adipose tissue. Chemerin elicits a variety of functions via chemokine-like receptor 1 (CMKLR1). The cardiovascular center in brain that regulates blood pressure (BP) is involved in pathophysiology of systemic hypertension. Thus, we explored the roles of brain chemerin/CMKLR1 on regulation of BP in spontaneously hypertensive rats (SHR). For this aim, we examined effects of intracerebroventricular (i.c.v.) injection of CMKLR1 small interfering (si)RNA on both systemic BP as measured by tail cuff system and protein expression in paraventricular nucleus (PVN) of SHR as determined by Western blotting. We also examined both central and peripheral protein expression of chemerin by Western blotting. Systolic BP of SHR but not normotensive Wistar Kyoto rats (WKY) was decreased by CMKLR1 siRNA. The decrease of BP by CMKLR1 siRNA persisted for 3 days. Protein expression of CMKLR1 in PVN of SHR tended to be increased compared with WKY, which was suppressed by CMKLR1 siRNA. Protein expression of chemerin in brain, peripheral plasma, and adipose tissue was not different between WKY and SHR. In summary, we for the first time revealed that the increased protein expression of CMKLR1 in PVN is at least partly responsible for systemic hypertension in SHR.

The Effect of Substrate Temperature on the Evaporative Behaviour and Desiccation Patterns of Foetal Bovine Serum Drops

The drying of bio-fluid drops results in the formation of complex patterns, which are morphologically and topographically affected by environmental conditions including temperature. We examine the effect of substrate temperatures between 20 °C and 40 °C, on the evaporative dynamics and dried deposits of foetal bovine serum (FBS) drops. The deposits consist of four zones: a peripheral protein ring, a zone of protein structures, a protein gel, and a central crystalline zone. We investigate the link between the evaporative behaviour, final deposit volume, and cracking. Drops dried at higher substrate temperatures in the range of 20 °C to 35 °C produce deposits of lower final volume. We attribute this to a lower water content and a more brittle gel in the deposits formed at higher temperatures. However, the average deposit volume is higher for drops dried at 40 °C compared to drops dried at 35 °C, indicating protein denaturation. Focusing on the protein ring, we show that the ring volume decreases with increasing temperature from 20 °C to 35 °C, whereas the number of cracks increases due to faster water evaporation. Interestingly, for deposits of drops dried at 40 °C, the ring volume increases, but the number of cracks also increases, suggesting an interplay between water evaporation and increasing strain in the deposits due to protein denaturation.

High-dimensional profiling reveals phenotypic heterogeneity and disease-specific alterations of granulocytes in COVID-19

Since the outset of the COVID-19 pandemic, increasing evidence suggests that the innate immune responses play an important role in the disease development. A dysregulated inflammatory state has been proposed as key driver of clinical complications in COVID-19, with a potential detrimental role of granulocytes. However, a comprehensive phenotypic description of circulating granulocytes in SARS-CoV-2-infected patients is lacking. In this study, we used high-dimensional flow cytometry for granulocyte immunophenotyping in peripheral blood collected from COVID-19 patients during acute and convalescent phases. Severe COVID-19 was associated with increased levels of both mature and immature neutrophils, and decreased counts of eosinophils and basophils. Distinct immunotypes were evident in COVID-19 patients, with altered expression of several receptors involved in activation, adhesion and migration of granulocytes (e.g. CD62L, CD11a/b, CD69, CD63, CXCR4). Paired sampling revealed recovery and phenotypic restoration of the granulocytic signature in the convalescent phase. The identified granulocyte immunotypes correlated with distinct sets of soluble inflammatory markers supporting pathophysiologic relevance. Furthermore, clinical features, including multi-organ dysfunction and respiratory function, could be predicted using combined laboratory measurements and immunophenotyping. This study provides a comprehensive granulocyte characterization in COVID-19 and reveals specific immunotypes with potential predictive value for key clinical features associated with COVID-19.SignificanceAccumulating evidence shows that granulocytes are key modulators of the immune response to SARS-CoV-2 infection and their dysregulation could significantly impact COVID-19 severity and patient recovery after virus clearance. In the present study, we identify selected immune traits in neutrophil, eosinophil and basophil subsets associated to severity of COVID-19 and to peripheral protein profiles. Moreover, computational modeling indicates that the combined use of phenotypic data and laboratory measurements can effectively predict key clinical outcomes in COVID-19 patients. Finally, patient-matched longitudinal analysis shows phenotypic normalization of granulocyte subsets 4 months after hospitalization. Overall, in this work we extend the current understanding of the distinct contribution of granulocyte subsets to COVID-19 pathogenesis.

Analysis of circulating protein aggregates reveals pathological hallmarks of amyotrophic lateral sclerosis

Blood-based biomarkers can be informative of brain disorders where protein aggregation play a major role. The proteome of plasma and circulating protein aggregates (CPA) reflect the inflammatory and metabolic state of the organism and can be predictive of system-level and/or organ-specific pathologies. CPA are enriched with heavy chain neurofilaments (NfH), key axonal constituents involved in brain aggregates formation and biomarkers of the fatal neurodegenerative disorder amyotrophic lateral sclerosis (ALS). Here we show that CPA and brain protein aggregates (BPA) from ALS differ in protein composition and appear as a combination of electron-dense large globular and small filamentous formations on transmission electron microscopy. CPA are highly enriched with proteins involved in the proteasome and energy metabolism. Compared to the human proteome, proteins within aggregates show distinct and tissue-dependent chemical features of aggregation propensity. The use of a TMTcalibrator™ proteomics workflow with ALS brain as calibrant reveals 4973 brain-derived low-abundance proteins in CPA, including the products of translation of 24 ALS risk genes. 285 of these (5.7%) are regulated in ALS CPA including FUS (p<0.05). CPA from both ALS and healthy controls affect cell viability when testing endothelial and PC12 neuronal cell lines, while CPA from ALS exert a more toxic effect at lower concentrations. The analysis of resistance to protease enzymes hydrolysis indicates an ALS-specific digestion pattern for NfH using enterokinase. This study reveals how peripheral protein aggregates are significantly enriched with brain proteins which are highly representative of ALS pathology and a potential alternative source of biomarkers and therapeutic targets for this incurable disorder.Significance StatementMolecular mechanism of neurodegeneration like protein aggregation are important brain-specific alterations which need to be addressed therapeutically. Recently described fluid biomarkers of neurodegenerative disorders provide means for stratification and monitoring of disease progression. Here we show that circulating protein aggregates are easily accessible in blood and reproduce important features of brain pathology for an incurable disorder like amyotrophic lateral sclerosis. They represent a source of biomarkers and of novel therapeutics for ALS.

Estimating the accuracy of the MARTINI model towards the investigation of Peripheral Protein-Membrane Interactions

Peripheral membrane proteins play a major role in numerous biological processes by transiently associating with cellular membranes, often with extreme membrane specificity. Because of the short-lived nature of these interactions,...

C-reactive protein concentration in bipolar disorder: association with genetic variants

Background Several recent studies have investigated the role of C-reactive protein (CRP) in bipolar disorder (BD), but few studies have directly investigated the interaction between CRP genetic variants and peripheral CRP concentration across different phases of BD. In this study, we aimed to replicate previous findings that demonstrated altered CRP levels in BD, and to investigate whether there is an association of peripheral protein expression with genetic variants in the CRP gene. Methods 221 patients were included in the study, of which 183 (all episodes, 46 not medicated, 174 medicated) were genotyped for CRP single-nucleotide polymorphisms (SNPs) shown to influence peripheral CRP protein expression (rs1800947, rs2808630, rs1417938, rs1205). Results There were no differences in CRP levels associated with the genotypes, only regarding the rs1205 SNP there were significantly different CRP protein expression between the genotypes when taking body mass index, age, BD polarity, subtype and leukocyte number into account. However, we could show significantly elevated CRP protein expression in manic patients compared to euthymic and depressed patients, independent from genotype. Medication was found to have no effect on CRP protein expression. Conclusions These results indicate that low grade inflammation might play a role in mania and might be rather a state than a trait marker of bipolar disorder.

Cell Surface GRP78 as a Death Receptor and an Anticancer Drug Target

Cell surface GRP78 (csGRP78, glucose-regulated protein 78 kDa) is preferentially overexpressed in aggressive, metastatic, and chemo-resistant cancers. GRP78 is best studied as a chaperone protein in the lumen of endoplasmic reticulum (ER), facilitating folding and secretion of the newly synthesized proteins and regulating protein degradation as an ER stress sensor in the unfolded protein pathway. As a cell surface signal receptor, multiple csGRP78 ligands have been discovered to date, and they trigger various downstream cell signaling pathways including pro-proliferative, pro-survival, and pro-apoptotic pathways. In this perspective, we evaluate csGRP78 as a cell surface death receptor and its prospect as an anticancer drug target. The pro-apoptotic ligands of csGRP78 discovered so far include natural proteins, monoclonal antibodies, and synthetic peptides. Even the secreted GRP78 itself was recently found to function as a pro-apoptotic ligand for csGRP78, mediating pancreatic -cell death. As csGRP78 is found to mainly configur as an external peripheral protein on cancer cell surface, how it can transmit death signals to the cytoplasmic environment remains enigmatic. With the recent encouraging results from the natural csGRP78 targeting pro-apoptotic monoclonal antibody PAT-SM6 in early-stage cancer clinical trials, the potential to develop a novel class of anticancer therapeutics targeting csGRP78 is becoming more compelling.