Secreted gelsolin inhibits DNGR-1-dependent cross-presentation and cancer immunity.

Cross-presentation of antigens from dead tumor cells by type 1 conventional dendritic cells (cDC1s) is thought to underlie priming of anti-cancer CD8+ T cells. cDC1 express high levels of DNGR-1 (a.k.a. CLEC9A), a receptor that binds to F-actin exposed by dead cell debris and promotes cross-presentation of associated antigens. Here, we show that secreted gelsolin (sGSN), an extracellular protein, decreases DNGR-1 binding to F-actin and cross-presentation of dead cell-associated antigens by cDC1s. Mice deficient in sGsn display increased DNGR-1-dependent resistance to transplantable tumors, especially ones expressing neoantigens associated with the actin cytoskeleton, and exhibit greater responsiveness to cancer immunotherapy. In human cancers, lower levels of intratumoral sGSN transcripts, as well as presence of mutations in proteins associated with the actin cytoskeleton, are associated with signatures of anti-cancer immunity and increased patient survival. Our results reveal a natural barrier to cross-presentation of cancer antigens that dampens anti-tumor CD8+ T cell responses.

Proteomic Analysis Identifies GSN as a Noninvasive Circulating Serum Biomarker for Predicting Early Recurrence of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is susceptible to early recurrence, but it lacks effective predictive biomarkers. In this study, we retrospectively selected 179 individuals as a discovery cohort (126 HCC patients and 53 liver cirrhosis (LC) patients) for screening candidate serum biomarkers of early recurrence based on data independent acquisition-mass spectrometry strategy. And then, the candidate biomarkers were validated in an additional independent cohort with 192 individuals (142 HCC patients and 50 LC patients) using parallel reaction monitoring targeted quantitative techniques (PXD047852). Eventually, we validated that gelsolin (GSN) concentrations were significantly lower in HCC than in LC (p < 0.0001), patients with low GSN concentrations had a poor prognosis (p < 0.0001), and GSN concentrations were significantly lower in early recurrence HCC than in late recurrence HCC (p < 0.0001). These trends were also observed in alpha-fetoprotein (AFP)-negative HCC patients. The area under the curve of machine-learning-based predictive model (GSN and microvascular invasion) for predicting early recurrence risk reached 0.803 (95% confidence interval (CI): 0.786-0.820) and maintained the same efficacy in AFP-negative patients. In conclusion, GSN is a novel serum biomarker for early recurrence of HCC. The model could provide timely warning to HCC patients at high risk of recurrence.

Maize actin depolymerizing factor 1 (ZmADF1) negatively regulates pollen development.

The normal development of pollen grains and the completion of double fertilization in embryos are crucial for both the sexual reproduction of angiosperms and grain production. Actin depolymerizing factor (ADF) regulates growth, development, and responses to biotic and abiotic stress by binding to actin in plants. In this study, the function of the ZmADF1 gene was validated through bioinformatic analysis, subcellular localization, overexpression in maize and Arabidopsis, and knockout via CRISPR/Cas9. The amino acid sequence of ZmADF1 exhibited high conservation and a similar tertiary structure to that of ADF homologs. Subcellular localization analysis revealed that ZmADF1 is localized mainly to the nucleus and cytoplasm. The ZmADF1 gene was specifically expressed in maize pollen, and overexpression of the ZmADF1 gene decreased the number of pollen grains in the anthers of transgenic Arabidopsis plants. The germination rate of pollen and the empty seed shell rate in the fruit pods of the overexpressing plants were significantly greater than those in the wild-type (WT) plants. In maize, the pollen viability of the knockout lines was significantly greater than that of both the WT and the overexpressing lines. Our results confirmed that the ZmADF1 gene was specifically expressed in pollen and negatively regulated pollen quantity, vigor, germination rate, and seed setting rate. This study provides insights into ADF gene function and possible pathways for improving high-yield maize breeding.

Daam2 Regulates Myelin Structure and the Oligodendrocyte Actin Cytoskeleton through Rac1 and Gelsolin.

Myelin is essential to neuronal health and CNS function, and oligodendrocytes (OLs) undergo a complex process of cytoskeletal remodeling to form compact myelin sheaths. We previously discovered that a formin protein, Dishevelled associated activator of morphogenesis 2 (Daam2), suppresses OL differentiation through Wnt signaling; however, its role in cytoskeletal control remains unknown. To investigate this, we used OL-specific Daam2 conditional knockout (Daam2 cKO) mice of either sex and found myelin decompaction during an active period of myelination in postnatal development and motor coordination deficits in adulthood. Using primary OL cultures, we found Daam2-depleted OLs showed morphologic dysregulation during differentiation, suggesting that Daam2 regulates the OL cytoskeleton. In vivo screening identified the actin regulators Rac1 and Gelsolin as possible effectors in Daam2-deficient OL cytoskeletal regulation. Using gain-of-function and loss-of-function (LOF) experiments in primary OLs, we found that Rac1 and Gelsolin operate downstream of Daam2 in OL differentiation, with Gelsolin and Daam2 promoting and inhibiting membrane spreading during late differentiation, respectively. In vivo experiments using Daam2 cKO mice revealed increased protein levels of Gelsolin in the developing white matter with no change in RNA levels, suggesting that Daam2 acts in a posttranslational manner to suppress Gelsolin levels. In vitro biochemical studies show Daam2 induces Gelsolin ubiquitination and degradation in OLs. Together, our studies show Daam2 is essential for formation of functional myelin through modulation of Gelsolin levels to regulate the OL cytoskeleton. These findings further demonstrate the critical role of cytoskeletal dynamics in myelination and reveal novel avenues for treatment of a variety of white matter diseases.SIGNIFICANCE STATEMENT Proper myelin formation is essential to CNS function, and oligodendrocytes (OLs) require extensive changes in the actin cytoskeleton to form myelin sheaths. Here, we show that the formin protein Dishevelled associated activator of morphogenesis 2 (Daam2) is necessary for myelin compaction during development and motor learning in adulthood. Further, we demonstrate that Daam2 regulates OL differentiation and morphology through actin regulators Rac1 and Gelsolin. Lastly, we find that Daam2 may control myelin compaction by modulating the ubiquitination and degradation of Gelsolin through recruitment of the E3 ubiquitin ligase Nedd4. These findings reveal novel pathways for regulating myelin structure and function during white matter development.

Role and therapeutic potential of gelsolin in atherosclerosis.

Atherosclerosis is the major pathophysiological basis of a variety of cardiovascular diseases and has been recognized as a lipid-driven chronic inflammatory disease. Gelsolin (GSN) is a member of the GSN family. The main function of GSN is to cut and seal actin filaments to regulate the cytoskeleton and participate in a variety of biological functions, such as cell movement, morphological changes, metabolism, apoptosis and phagocytosis. Recently, more and more evidences have demonstrated that GSN is Closely related to atherosclerosis, involving lipid metabolism, inflammation, cell proliferation, migration and thrombosis. This article reviews the role of GSN in atherosclerosis from inflammation, apoptosis, angiogenesis and thrombosis.

Gelsolin from mussel's catch muscle.

Proteins of the gelsolin family are Ca2+-dependent, multifunctional, actin-binding proteins containing three (S1-S3, about 40 kDa) or six (S1-S6, about 80 kDa) highly conserved repeats in the amino acid sequence. The pattern of interaction of these proteins with actin is complex: they can sever actin filaments; promote polymer nucleation after binding to two actin monomers; and cap the growing barbed end of actin filaments. In the present study, an actin polymerizing factor (46 kDa) from the adductor muscle of a bivalve mollusc has been discovered and identified for the first time. This protein has turned out to belong to the gelsolin family of actin regulatory proteins. The expression of gelsolin-like proteins in the tissues of bivalves was predicted after analyzing their proteome, but this is the first study where an actually expressed protein has been found. A primary determination of its physicochemical properties such as molecular weight, charge, resistance to urea, influence on actin polymerization by viscosity, and light scattering is carried out and the molecular structure analyzed.

Plasma gelsolin levels are associated with diabetes, sex, race, and poverty.

BACKGROUND: The growing epidemic of the inflammation-related metabolic disease, type 2 diabetes mellitus, presents a challenge to improve our understanding of potential mechanisms or biomarkers to prevent or better control this age-associated disease. A gelsolin isoform is secreted into the plasma as part of the extracellular actin scavenger system which serves a protective role by digesting and removing actin filaments released from damaged cells. Recent data indicate a role for decreased plasma gelsolin (pGSN) levels as a biomarker of inflammatory conditions. Extracellular vesicles (EVs), a heterogeneous group of cell-derived membranous structures involved in intercellular signaling, have been implicated in metabolic and inflammatory diseases including type 2 diabetes mellitus. We examined whether pGSN levels were associated with EV concentration and inflammatory plasma proteins in individuals with or without diabetes. METHODS: We quantified pGSN longitudinally (n = 104) in a socioeconomically diverse cohort of middle-aged African American and White study participants with and without diabetes mellitus. Plasma gelsolin levels were assayed by ELISA. EV concentration (sub-cohort n = 40) was measured using nanoparticle tracking analysis. Inflammatory plasma proteins were assayed on the SomaScan® v4 proteomic platform. RESULTS: pGSN levels were lower in men than women. White individuals with diabetes had significantly lower levels of pGSN compared to White individuals without diabetes and to African American individuals either with or without diabetes. For adults living below poverty, those with diabetes had lower pGSN levels than those without diabetes. Adults living above poverty had similar pGSN levels regardless of diabetes status. No correlation between EV concentrations and pGSN levels was identified (r = - 0.03; p = 0.85). Large-scale exploratory plasma protein proteomics revealed 47 proteins that significantly differed by diabetes status, 19 of which significantly correlated with pGSN levels, including adiponectin. CONCLUSIONS: In this cohort of racially diverse individuals with and without diabetes, we found differences in pGSN levels with diabetes status, sex, race, and poverty. We also report significant associations of pGSN with the adipokine, adiponectin, and other inflammation- and diabetes-related proteins. These data provide mechanistic insights into the relationship of pGSN and diabetes.

Quorum Sensing by Gelsolin Regulates Programmed Cell Death 4 Expression and a Density-Dependent Phenotype in Macrophages.

Quorum-sensing mechanisms that sense the density of immune cells at the site of inflammation to initiate inflammation resolution have recently been demonstrated as a major determinant of the inflammatory response. We observed a density-dependent increase in expression of the inflammatory tumor suppressor protein programmed cell death 4 (PDCD4) in mouse macrophage cells. Conditioned medium from high-density cells upregulated PDCD4 expression, revealing the presence of a secreted factor(s) acting as a macrophage quorum sensor. Secreted gelsolin (GSN) was identified as the quorum-sensing autoinducer. Alteration of GSN levels changed PDCD4 expression and the density-dependent phenotype of cells. LPS induced the expression of microRNA miR-21, which downregulated both GSN and PDCD4 expression, and reversed the high-density phenotype. The high-density phenotype was correlated with an anti-inflammatory gene expression program, which was counteracted by inflammatory stimulus. Together, our observations establish the miR-21-GSN-PDCD4 regulatory network as a crucial mediator of a macrophage quorum-sensing mechanism for the control of inflammatory responses.

Cryopreservation, in addition to protein tyrosine phosphorylation, alters the distribution of phosphatidyl inositol bisphosphate and the localization of cytoskeletal and signaling proteins (gelsolin, tyrosine kinase c-SRC and phospholipase C-ζ) in the perinuclear theca of boar sperm.

Cryopreservation of boar spermatozoa affects the perinuclear theca (PT) and involves several proteins and molecules that play important roles during capacitation and the acrosomal reaction. The objective of the present study was to evaluate whether the deleterious effects of cryopreservation in addition to protein tyrosine phosphorylation are accompanied by changes in the distribution of phosphatidyl inositol bisphosphate (PIP2) and the localization of cytoskeletal and signaling proteins in the perinuclear theca of cryopreserved boar spermatozoa. For this purpose, by immunocytochemistry (IC) the changes in localization of phosphorylated proteins in tyrosine residues, gelsolin, c-SRC kinase and PLC-ζ, as well as in the distribution of phosphatidyl inositol bisphosphate were analyzed in thawed spermatozoa (T) non capacitated (NC), capacitated (C) and in those with acrosomal reaction (AR) and compared with fresh spermatozoa (F) under the same physiological status. Western blotting (WB) and co-immunoprecipitation were performed to confirm the presence of these proteins in PT and to determine the interaction between these molecules. IC showed that immunostaining for phosphorylated proteins significantly increased in the acrosomal region and flagellum in TNC spermatozoa (p < 0.05). The proportion of cells displaying immunolabeling for gelsolin in the acrosomal region decreased after capacitation in cryopreserved spermatozoa; the same change was found (p < 0.05) in the proportion of spermatozoa immunoreactive to PIP2 in the sperm head. c-SRC was observed in the equatorial segment and acrosomal region, subdomains that coincide with the site where phosphorylated proteins were detected. PLC-ζ immunolocalization in fresh spermatozoa underwent changes after capacitation and acrosomal reaction, with a significant increase in the equatorial segment and post-acrosomal region in cryopreserved spermatozoa (p < 0.05). WB analysis indicated the presence of gelsolin, c-SRC and PLC-ζ in PT; besides, we confirmed that gelsolin co-immunoprecipitated with c-SRC and PLC-ζ, which changes according to the physiological state of spermatozoa. As a conclusion, cryopreservation together with increased immunodetection of tyrosine phosphorylated proteins decreases the detection of PIP2 and alters the immunolocalization patterns of gelsolin, c-SRC and PLC-ζ in the PT in boar spermatozoa.

Insights into the evolution of regulated actin dynamics via characterization of primitive gelsolin/cofilin proteins from Asgard archaea.

Asgard archaea genomes contain potential eukaryotic-like genes that provide intriguing insight for the evolution of eukaryotes. The eukaryotic actin polymerization/depolymerization cycle is critical for providing force and structure in many processes, including membrane remodeling. In general, Asgard genomes encode two classes of actin-regulating proteins from sequence analysis, profilins and gelsolins. Asgard profilins were demonstrated to regulate actin filament nucleation. Here, we identify actin filament severing, capping, annealing and bundling, and monomer sequestration activities by gelsolin proteins from Thorarchaeota (Thor), which complete a eukaryotic-like actin depolymerization cycle, and indicate complex actin cytoskeleton regulation in Asgard organisms. Thor gelsolins have homologs in other Asgard archaea and comprise one or two copies of the prototypical gelsolin domain. This appears to be a record of an initial preeukaryotic gene duplication event, since eukaryotic gelsolins are generally comprise three to six domains. X-ray structures of these proteins in complex with mammalian actin revealed similar interactions to the first domain of human gelsolin or cofilin with actin. Asgard two-domain, but not one-domain, gelsolins contain calcium-binding sites, which is manifested in calcium-controlled activities. Expression of two-domain gelsolins in mammalian cells enhanced actin filament disassembly on ionomycin-triggered calcium release. This functional demonstration, at the cellular level, provides evidence for a calcium-controlled Asgard actin cytoskeleton, indicating that the calcium-regulated actin cytoskeleton predates eukaryotes. In eukaryotes, dynamic bundled actin filaments are responsible for shaping filopodia and microvilli. By correlation, we hypothesize that the formation of the protrusions observed from Lokiarchaeota cell bodies may involve the gelsolin-regulated actin structures.

Gelsolin, an Actin-Binding Protein: Bioinformatic Analysis and Functional Significance in Urothelial Bladder Carcinoma.

The involvement of the actin-regulatory protein, gelsolin (GSN), in neoplastic transformation has been reported in different cancers including bladder cancer. However, the exact mechanism by which GSN influences bladder cancer development is not well understood. Here, we sought to reveal the functional significance of GSN in bladder cancer by undertaking a comprehensive bioinformatic analysis of TCGA datasets and through the assessment of multiple biological functions. GSN expression was knocked down in bladder cancer cell lines with two siRNA isoforms targeting GSN. Proliferation, migration, cell cycle and apoptosis assays were carried out. GSN expression, enrichment analysis, protein-protein interaction and immune infiltration analysis were verified through online TCGA tools. The data indicated that GSN expression is associated with bladder cancer proliferation, migration and enhanced cell apoptosis through regulation of NF-κB expression. GSN expression correlated with various inflammatory cells and may influence the immunity of the tumor microenvironment. Computational analysis identified several interacting partners which are associated with cancer progression and patient outcome. The present results demonstrate that GSN plays an important role in bladder cancer pathogenesis and may serve as a potential biomarker and therapeutic target for cancer therapy.

Zero-mode waveguides visualize the first steps during gelsolin-mediated actin filament formation.

Actin filament dynamics underlie key cellular processes. Although the elongation of actin filaments has been extensively studied, the mechanism of nucleation remains unclear. The micromolar concentrations needed for filament formation have prevented direct observation of nucleation dynamics on the single molecule level. To overcome this limitation, we have used the attoliter excitation volume of zero-mode waveguides to directly monitor the early steps of filament assembly. Immobilizing single gelsolin molecules as a nucleator at the bottom of the zero-mode waveguide, we could visualize the actin filament nucleation process. The process is surprisingly dynamic, and two distinct populations during gelsolin-mediated nucleation are observed. The two populations are defined by the stability of the actin dimers and determine whether elongation occurs. Furthermore, by using an inhibitor to block flattening, a conformational change in actin associated with filament formation, elongation was prevented. These observations indicate that a conformational transition and pathway competition determine the nucleation of gelsolin-mediated actin filament formation.

The actin polymerization factor Diaphanous and the actin severing protein Flightless I collaborate to regulate sarcomere size.

The sarcomere is the basic contractile unit of muscle, composed of repeated sets of actin thin filaments and myosin thick filaments. During muscle development, sarcomeres grow in size to accommodate the growth and function of muscle fibers. Failure in regulating sarcomere size results in muscle dysfunction; yet, it is unclear how the size and uniformity of sarcomeres are controlled. Here we show that the formin Diaphanous is critical for the growth and maintenance of sarcomere size: Dia sets sarcomere length and width through regulation of the number and length of the actin thin filaments in the Drosophila flight muscle. To regulate thin filament length and sarcomere size, Dia interacts with the Gelsolin superfamily member Flightless I (FliI). We suggest that these actin regulators, by controlling actin dynamics and turnover, generate uniformly sized sarcomeres tuned for the muscle contractions required for flight.

Myosin and gelsolin cooperate in actin filament severing and actomyosin motor activity.

Actin is a major intracellular protein with key functions in cellular motility, signaling, and structural rearrangements. Its dynamic behavior, such as polymerization and depolymerization of actin filaments in response to intracellular and extracellular cues, is regulated by an abundance of actin binding proteins. Out of these, gelsolin is one of the most potent for filament severing. However, myosin motor activity also fragments actin filaments through motor-induced forces, suggesting that these two proteins could cooperate to regulate filament dynamics and motility. To test this idea, we used an in vitro motility assay, where actin filaments are propelled by surface-adsorbed heavy meromyosin (HMM) motor fragments. This allows studies of both motility and filament dynamics using isolated proteins. Gelsolin, at both nanomolar and micromolar Ca2+ concentration, appreciably enhanced actin filament severing caused by HMM-induced forces at 1 mM MgATP, an effect that was increased at higher HMM motor density. This finding is consistent with cooperativity between actin filament severing by myosin-induced forces and by gelsolin. We also observed reduced sliding velocity of the HMM-propelled filaments in the presence of gelsolin, providing further support of myosin-gelsolin cooperativity. Total internal reflection fluorescence microscopy-based single molecule studies corroborated that the velocity reduction was a direct effect of gelsolin binding to the filament and revealed different filament severing pattern of stationary and HMM propelled filaments. Overall, the results corroborate cooperative effects between gelsolin-induced alterations in the actin filaments and changes due to myosin motor activity leading to enhanced F-actin severing of possible physiological relevance.

Recombinant human plasma gelsolin reverses increased permeability of the blood-brain barrier induced by the spike protein of the SARS-CoV-2 virus.

BACKGROUND: Plasma gelsolin (pGSN) is an important part of the blood actin buffer that prevents negative consequences of possible F-actin deposition in the microcirculation and has various functions during host immune response. Recent reports reveal that severe COVID-19 correlates with reduced levels of pGSN. Therefore, using an in vitro system, we investigated whether pGSN could attenuate increased permeability of the blood-brain barrier (BBB) during its exposure to the portion of the SARS-CoV-2 spike protein containing the receptor binding domain (S1 subunit). MATERIALS AND METHODS: Two- and three-dimensional models of the human BBB were constructed using the human cerebral microvascular endothelial cell line hCMEC/D3 and exposed to physiologically relevant shear stress to mimic perfusion in the central nervous system (CNS). Trans-endothelial electrical resistance (TEER) as well as immunostaining and Western blotting of tight junction (TJ) proteins assessed barrier integrity in the presence of the SARS-CoV-2 spike protein and pGSN. The IncuCyte Live Imaging system evaluated the motility of the endothelial cells. Magnetic bead-based ELISA was used to determine cytokine secretion. Additionally, quantitative real-time PCR (qRT-PCR) revealed gene expression of proteins from signaling pathways that are associated with the immune response. RESULTS: pGSN reversed S1-induced BBB permeability in both 2D and 3D BBB models in the presence of shear stress. BBB models exposed to pGSN also exhibited attenuated pro-inflammatory signaling pathways (PI3K, AKT, MAPK, NF-κB), reduced cytokine secretion (IL-6, IL-8, TNF-α), and increased expression of proteins that form intercellular TJ (ZO-1, occludin, claudin-5). CONCLUSION: Due to its anti-inflammatory and protective effects on the brain endothelium, pGSN has the potential to be an alternative therapeutic target for patients with severe SARS-CoV-2 infection, especially those suffering neurological complications of COVID-19.

Optogenetic activation of intracellular antibodies for direct modulation of endogenous proteins.

Intracellular antibodies have become powerful tools for imaging, modulating and neutralizing endogenous target proteins. Here, we describe an optogenetically activated intracellular antibody (optobody) consisting of split antibody fragments and blue-light inducible heterodimerization domains. We expanded this optobody platform by generating several optobodies from previously developed intracellular antibodies, and demonstrated that photoactivation of gelsolin and ß2-adrenergic receptor (ß2AR) optobodies suppressed endogenous gelsolin activity and ß2AR signaling, respectively.

Gelsolin is an important mediator of Angiotensin II-induced activation of cardiac fibroblasts and fibrosis.

Myocardial fibrosis is a characteristic of various cardiomyopathies, and myocardial fibroblasts play a central role in this process. Gelsolin (GSN) is an actin severing and capping protein that regulates actin assembly and may be involved in fibroblast activation. While the role of GSN in mechanical stress-mediated cardiac fibrosis has been explored, its role in myocardial fibrosis in the absence of mechanical stress is not defined. In this study, we investigated the role of GSN in myocardial fibrosis induced by Angiotensin II (Ang II), a profibrotic hormone that is elevated in cardiovascular disease. We utilized mice lacking GSN (Gsn-/- ) and cultured primary adult cardiac fibroblasts (cFB). In vivo, Ang II infusion in mice resulted in significantly less severe myocardial fibrosis in Gsn-/- compared with Gsn+/+ mice, along with diminished activation of the TGFß1-Smad2/3 pathway, and reduced expression of cardiac extracellular matrix proteins (collagen, fibronectin, periostin). Moreover, Gsn-deficient hearts exhibited suppressed activity of the AMPK pathway and its downstream effectors, mTOR and P70S6Kinase, which could contribute to the suppressed TGFß1 activity. In vitro, the Ang II-induced activation of cFBs was reduced in Gsn-deficient fibroblasts evident from decreased expression of αSMA and periostin, diminished actin filament turnover; which also exhibited reduced activity of the AMPK-mTOR pathway, and P70S6K phosphorylation. AMPK inhibition compensated for the loss of GSN, restored the levels of G-actin in Gsn-/- cFBs and promoted activation to myofibroblasts by increasing αSMA and periostin levels. This study reveals a novel role for GSN in mediating myocardial fibrosis by regulating the AMPK-mTOR-P70S6K pathway in cFB activation independent from mechanical stress-induced factors.

Hypogelsolinemia and Decrease in Blood Plasma Sphingosine-1-Phosphate in Patients Diagnosed with Severe Acute Pancreatitis.

BACKGROUND: Acute pancreatitis (AP) is a frequent hospitalization cause of patients suffering from gastrointestinal disorders. Gelsolin has an ability to bind bioactive lipids including different sphingolipids engaged in inflammatory response. Importantly, hypogelsolinemia was observed in patients with different states of acute and chronic inflammation. AIMS: The aim of the present study was to assess the interplay of blood plasma gelsolin and blood plasma sphingosine-1-phosphate (S1P) concentration in patients diagnosed with acute pancreatitis. MATERIALS AND METHODS: To assess the concentration of gelsolin and S1P, immunoblotting and HPLC technique were employed, respectively. Additionally, the concentrations of amylase, lipase, C-reactive protein (CRP), procalcitonin (PCT) and the number of white blood cells (WBC) and platelet (PLT) were recorded. RESULTS: We found that both pGSN and S1P concentrations in the plasma of the AP patients were significantly lower (pGSN ~ 15-165 mg/L; S1P ~ 100-360 pmol/mL) when compared to the levels of pGSN and S1P in a control group (pGSN ~ 130-240 mg/L; S1P ~ 260-400 pmol/mL). Additionally, higher concentrations of CRP, WBC, amylase and lipase were associated with low level of gelsolin in the blood of AP patients. No correlations between the level of PCT and PLT with gelsolin concentration were noticed. CONCLUSION: Plasma gelsolin and S1P levels decrease during severe acute pancreatitis. Simultaneous assessment of pGSN and S1P can be useful in development of more accurate diagnostic strategies for patients with severe acute pancreatitis.

Association of plasma gelsolin with frailty phenotype and mortality among octogenarian community-dwelling men: a cohort study.

BACKGROUND: Biomarkers are needed for frailty, a common phenotype often associated with muscle loss in older people. Plasma gelsolin (pGSN) is a protein largely synthesized and secreted by skeletal muscle. AIMS: To investigate whether pGSN could be a biomarker of the frailty phenotype and predict mortality. METHODS: A homogenous cohort of males (born 1919-1934, baseline n = 3490) has been followed since the 1960s. In 2010/11, frailty phenotypes by modified Fried criteria were assessed. pGSN was measured in a convenience subset (n = 469, mean age 83) and re-measured in survivors (n = 127) in 2017. Mortality through December 31, 2018 was retrieved from national registers. Regression models were used for analyses. RESULTS: Of 469 males, 152 (32.4%) were robust, 284 (60.6%) prefrail, and 33 (7.0%) frail in 2010/11. There was a graded (p = 0.018) association between pGSN (mean 58.1 ug/mL, SD 9.3) and frailty. After multivariable adjustment, higher pGSN levels were associated with lower odds of having contemporaneous phenotypic prefrailty (OR per 1 SD 0.73, 95% CI 0.58-0.92) and frailty (OR per 1 SD 0.70, 95% CI 0.44-1.11). By 2018, 179 males (38.2%) had died, and higher baseline pGSN predicted a lower 7-year mortality rate (HR per 1 SD 0.85, 95% CI 0.72-1.00). pGSN concentrations in 2010/11 and 2017 were correlated (n = 127, r = 0.34, p < 0.001). DISCUSSION: Higher baseline pGSN concentrations were associated with a persistently robust phenotype and lower mortality rate over 7 years in a cohort of octogenarian males with high socioeconomic status and may be a promising laboratory biomarker for the development of a frailty phenotype.

CapG promoted nasopharyngeal carcinoma cell motility involving Rho motility pathway independent of ROCK.

BACKGROUND: Gelsolin-like capping actin protein (CapG) modulates actin dynamics and actin-based motility with a debatable role in tumorigenic progression. The motility-associated functions and potential molecular mechanisms of CapG in nasopharyngeal carcinoma (NPC) remain unclear. METHODS: CapG expression was detected by immunohistochemistry in a cohort of NPC tissue specimens and by Western blotting assay in a variety of NPC cell lines. Loss of function and gain of function of CapG in scratch wound-healing and transwell assays were performed. Inactivation of Rac1 and ROCK with the specific small molecular inhibitors was applied to evaluate CapG's role in NPC cell motility. GTP-bound Rac1 and phosphorylated-myosin light chain 2 (p-MLC2) were measured in the ectopic CapG overexpressing cells. Finally, CapG-related gene set enrichment analysis was conducted to figure out the significant CapG-associated pathways in NPC. RESULTS: CapG disclosed increased level in the poorly differentiated NPC tissues and highly metastatic cells. Knockdown of CapG reduced NPC cell migration and invasion in vitro, while ectopic CapG overexpression showed the opposite effect. Ectopic overexpression of CapG compensated for the cell motility loss caused by simultaneous inactivation of ROCK and Rac1 or inactivation of ROCK alone. GTP-bound Rac1 weakened, and p-MLC2 increased in the CapG overexpressing cells. Bioinformatics analysis validated a positive correlation of CapG with Rho motility signaling, while Rac1 motility pathway showed no significant relationship. CONCLUSIONS: The present findings highlight the contribution of CapG to NPC cell motility independent of ROCK and Rac1. CapG promotes NPC cell motility at least partly through MLC2 phosphorylation and contradicts with Rac1 activation.