Identification of an osteopontin-derived peptide that binds neuropilin-1 and activates vascular repair responses and angiogenesis.

The osteopontin-derived peptide FOL-005 stimulates hair growth. Using ligand-receptor glyco-capture technology we identified neuropilin-1 (NRP-1), a known co-receptor for vascular endothelial growth factor (VEGF) receptors, as the most probable receptor for FOL-005 and the more stable analogue FOL-026. X-ray diffraction and microscale thermophoresis analysis revealed that FOL-026 shares binding site with VEGF in the NRP-1 b1-subdomain. Stimulation of human umbilical vein endothelial cells with FOL-026 resulted in phosphorylation of VEGFR-2, ERK1/2 and AKT, increased cell growth and migration, stimulation of endothelial tube formation and inhibition of apoptosis in vitro. FOL-026 also promoted angiogenesis in vivo as assessed by subcutaneous Matrigel plug and hind limb ischemia models. NRP-1 knock-down or treatment of NRP-1 antagonist EG00229 blocked the stimulatory effects of FOL-026 on endothelial cells. Exposure of human coronary artery smooth muscle cells to FOL-026 stimulated cell growth, migration, inhibited apoptosis, and induced VEGF gene expression and VEGFR-2/AKT phosphorylation by an NRP-1-dependent mechanism. RNA sequencing showed that FOL-026 activated pathways involved in tissue repair. These findings identify NRP-1 as the receptor for FOL-026 and show that its biological effects mimic that of growth factors binding to the VEGF receptor family. They also suggest that FOL-026 may have therapeutical potential in conditions that require vascular repair and/or enhanced angiogenesis.

Transforming growth factor-ß2 is associated with atherosclerotic plaque stability and lower risk for cardiovascular events.

AIMS: Transforming growth factor-beta (TGF-ß) exists in three isoforms TGF-ß1, -ß2, and -ß3. TGF-ß1 has been suggested to be important for maintaining plaque stability, yet the role of TGF-ß2 and -ß3 in atherosclerosis remains to be investigated.This study explores the association of the three isoforms of TGF-ß with plaque stability in the human atherosclerotic disease. METHODS AND RESULTS: TGF-ß1, -ß2, and -ß3 proteins were quantified in 223 human carotid plaques by immunoassays. Indications for the endarterectomy were: symptomatic carotid plaque with stenosis >70% or without symptoms and >80% stenosis. Plaque mRNA levels were assessed by RNA sequencing. Plaque components and extracellular matrix were measured histologically and biochemically. Matrix metalloproteinases and monocyte chemoattractant protein-1 (MCP-1) was measured with immunoassays. The effect of TGF-ß2 on inflammation and protease activity was investigated in vitro using THP-1 and RAW264.7 macrophages. Patients were followed longitudinally for cardiovascular (CV) events.TGF-ß2 was the most abundant isoform and was increased at both protein and mRNA levels in asymptomatic plaques. TGF-ß2 was the main determinant separating asymptomatic plaques in an Orthogonal Projections to Latent Structures Discriminant Analysis. TGF-ß2 correlated positively to features of plaque stability and inversely to markers of plaque vulnerability. TGF-ß2 was the only isoform inversely correlated to the matrix-degrading matrix metalloproteinase-9 and inflammation in the plaque tissue. In vitro, TGF-ß2 pre-treatment reduced MCP-1 gene and protein levels as well as matrix metalloproteinase-9 gene levels and activity. Patients with plaques with high TGF-ß2 levels had a lower risk to suffer from future CV events. CONCLUSIONS: TGF-ß2 is the most abundant TGF-ß isoform in human plaques and may maintain plaque stability by decreasing inflammation and matrix degradation.

Ablation of GPR56 Causes ß-Cell Dysfunction by ATP Loss through Mistargeting of Mitochondrial VDAC1 to the Plasma Membrane.

The activation of G Protein-Coupled Receptor 56 (GPR56), also referred to as Adhesion G-Protein-Coupled Ceceptor G1 (ADGRG1), by Collagen Type III (Coll III) prompts cell growth, proliferation, and survival, among other attributes. We investigated the signaling cascades mediating this functional effect in relation to the mitochondrial outer membrane voltage-dependent anion Channel-1 (VDAC1) expression in pancreatic ß-cells. GPR56KD attenuated the Coll III-induced suppression of P70S6K, JNK, AKT, NFκB, STAT3, and STAT5 phosphorylation/activity in INS-1 cells cultured at 20 mM glucose (glucotoxicity) for 72 h. GPR56-KD also increased Chrebp, Txnip, and Vdac1 while decreasing Vdac2 mRNA expression. In GPR56-KD islet ß-cells, Vdac1 was co-localized with SNAP-25, demonstrating its plasma membrane translocation. This resulted in ATP loss, reduced cAMP production and impaired glucose-stimulated insulin secretion (GSIS) in INS-1 and human EndoC ßH1 cells. The latter defects were reversed by an acute inhibition of VDAC1 with an antibody or the VDAC1 inhibitor VBIT-4. We demonstrate that Coll III potentiates GSIS by increasing cAMP and preserving ß-cell functionality under glucotoxic conditions in a GPR56-dependent manner by attenuating the inflammatory response. These results emphasize GPR56 and VDAC1 as drug targets in conditions with impaired ß-cell function.

Antibodies against apoB100 peptide 210 inhibit atherosclerosis in apoE-/- mice.

Atherosclerotic plaques are characterized by an accumulation and subsequent oxidation of LDL, resulting in adaptive immune responses against formed or exposed neoepitopes of the LDL particle. Autoantibodies against native p210, the 3136-3155 amino acid sequence of the LDL protein apolipoprotein B-100 (apoB100) are common in humans and have been associated with less severe atherosclerosis and decreased risk for cardiovascular events in clinical studies. However, whether apoB100 native p210 autoantibodies play a functional role in atherosclerosis is not known. In the present study we immunized apoE-/- mice with p210-PADRE peptide to induce an antibody response against native p210. We also injected mice with murine monoclonal IgG against native p210. Control groups were immunized with PADRE peptide alone or with control murine monoclonal IgG. Immunization with p210-PADRE induced an IgG1 antibody response against p210 that was associated with reduced atherosclerotic plaque formation in the aorta and reduced MDA-LDL content in the lesions. Treatment with monoclonal p210 IgG produced a similar reduction in atherosclerosis as immunization with p210-PADRE. Our findings support an atheroprotective role of antibodies against the apoB100 native p210 and suggest that vaccines that induce the expression of native p210 IgG represent a potential therapeutic strategy for lowering cardiovascular risk.

The proteoglycan mimecan is associated with carotid plaque vulnerability and increased risk of future cardiovascular death.

BACKGROUND AND AIMS: A vulnerable plaque is an atherosclerotic plaque that is rupture-prone with a higher risk to cause cardiovascular symptoms such as myocardial infarction or stroke. Mimecan or osteoglycin is a small leucine-rich proteoglycan, important for collagen fibrillogenesis, that has been implicated in atherosclerotic disease, yet the role of mimecan in human atherosclerotic disease remains unknown. METHODS: 196 human atherosclerotic carotid plaques were immunostained for mimecan. Smooth muscle cells, macrophages and intraplaque haemorrhage were also measured with immunohistochemistry. Neutral lipids were stained with Oil Red O and calcium deposits were quantified. Plaque homogenate levels of MCP-1, IL-6 and MIP-1ß were measured using a Proximity Extension Assay and MMP-9 levels were measured using Mesoscale. Glycosaminoglycans, collagen and elastin were assessed by colorimetric assays and TGF-ß1, ß2 and ß3 were measured using a multiplex assay. Mimecan gene expression in THP-1 derived macrophages was quantified by qPCR and protein expression in vitro was visualized with immunofluorescence. Cardiovascular events were registered using medical charts and national registers during follow-up. RESULTS: Mimecan correlated positively with plaque area of lipids, macrophages, intraplaque haemorrhage and inversely with smooth muscle cell staining. Mimecan also correlated positively with plaque levels of MMP-9 and MCP-1. Mimecan was upregulated in THP-1 derived macrophages upon stimulation with MCP-1. Patients with high levels of mimecan (above median) had higher risk for cardiovascular death. CONCLUSIONS: This study indicates that mimecan is associated with a vulnerable plaque phenotype, possibly regulated by plaque inflammation. In line, plaque levels of mimecan independently predict future cardiovascular death.

Inhibitory effect of UDP-glucose on cAMP generation and insulin secretion.

Type-2 diabetes (T2D) is a global disease caused by the inability of pancreatic ß-cells to secrete adequate insulin. However, the molecular mechanisms underlying the failure of ß-cells to respond to glucose in T2D remains unknown. Here, we investigated the relative contribution of UDP-glucose (UDP-G), a P2Y14-specific agonist, in the regulation of insulin release using human isolated pancreatic islets and INS-1 cells. P2Y14 was expressed in both human and rodent pancreatic ß-cells. Dose-dependent activation of P2Y14 by UDP-G suppressed glucose-stimulated insulin secretion (GSIS) and knockdown of P2Y14 abolished the UDP-G effect. 12-h pretreatment of human islets with pertussis-toxin (PTX) improved GSIS and prevented the inhibitory effect of UDP-G on GSIS. UDP-G on GSIS suppression was associated with suppression of cAMP in INS-1 cells. UDP-G decreased the reductive capacity of nondiabetic human islets cultured at 5 mm glucose for 72 h and exacerbated the negative effect of 20 mm glucose on the cell viability during culture period. T2D donor islets displayed a lower reductive capacity when cultured at 5 mm glucose for 72 h that was further decreased in the presence of 20 mm glucose and UDP-G. Presence of a nonmetabolizable cAMP analog during culture period counteracted the effect of glucose and UDP-G. Islet cultures at 20 mm glucose increased apoptosis, which was further amplified when UDP-G was present. UDP-G modulated glucose-induced proliferation of INS-1 cells. The data provide intriguing evidence for P2Y14 and UDP-G's role in the regulation of pancreatic ß-cell function.

Syndecan-4 Protects the Heart From the Profibrotic Effects of Thrombin-Cleaved Osteopontin.

Background Pressure overload of the heart occurs in patients with hypertension or valvular stenosis and induces cardiac fibrosis because of excessive production of extracellular matrix by activated cardiac fibroblasts. This initially provides essential mechanical support to the heart, but eventually compromises function. Osteopontin is associated with fibrosis; however, the underlying signaling mechanisms are not well understood. Herein, we examine the effect of thrombin-cleaved osteopontin on fibrosis in the heart and explore the role of syndecan-4 in regulating cleavage of osteopontin. Methods and Results Osteopontin was upregulated and cleaved by thrombin in the pressure-overloaded heart of mice subjected to aortic banding. Cleaved osteopontin was higher in plasma from patients with aortic stenosis receiving crystalloid compared with blood cardioplegia, likely because of less heparin-induced inhibition of thrombin. Cleaved osteopontin and the specific osteopontin peptide sequence RGDSLAYGLR that is exposed after thrombin cleavage both induced collagen production in cardiac fibroblasts. Like osteopontin, the heparan sulfate proteoglycan syndecan-4 was upregulated after aortic banding. Consistent with a heparan sulfate binding domain in the osteopontin cleavage site, syndecan-4 was found to bind to osteopontin in left ventricles and cardiac fibroblasts and protected osteopontin from cleavage by thrombin. Shedding of the extracellular part of syndecan-4 was more prominent at later remodeling phases, at which time levels of cleaved osteopontin were increased. Conclusions Thrombin-cleaved osteopontin induces collagen production by cardiac fibroblasts. Syndecan-4 protects osteopontin from cleavage by thrombin, but this protection is lost when syndecan-4 is shed in later phases of remodeling, contributing to progression of cardiac fibrosis.

COVID-19 and Possible Pharmacological Preventive Options.

The dreadful fear of the coronavirus disease 2019 (COVID-19), which is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with the deadly consequences, requires rapid development of pharmacological cures. The objective of this review is to speculate about possible pharmacological options, already available today to prevent or treat the COVID-19 in the early stage of its outbreak. A literature search across PubMed and internet was conducted. A number of studies dealing with COVID-19 were identified. The data elucidated that increased pro-inflammatory and decreased anti-inflammatory cytokines in combination with hypoxia, thromboembolism and pneumonia are involved in the pathogenesis of SARS-CoV-2 infection. Although many drugs has been tested in monotherapy regimen with varying outcome or without desirable effect, there is still hope for better results by simultaneously targeting the virus itself and its symptoms. Theoretically, a mixture of at least two available antiviral drugs in combination with other anti-pathogenic and immune system-enhancing drugs or combination of antiviral drugs with convalescent plasma seems likely to have much better effect than the monotherapy regimen of either of these drugs.

Orphan G-protein coupled receptor 183 (GPR183) potentiates insulin secretion and prevents glucotoxicity-induced ß-cell dysfunction.

The expression and functional impact of most orphan G-protein coupled receptors (GPCRs) in ß-cell is not fully understood. Microarray expression indicated that 36 orphan GPCRs are restricted in human islets, while 55 receptors overlapped between human islets and INS-1 cells. GPR183 showed higher expression in diabetic compared to non-diabetic human islets. GPR183 expression co-localized with ß-cells while it was lacking in α-cells in human islets. The GPR183 agonist (7α-25-DHC) potentiated insulin secretion and protected against glucotoxicity-induced ß-cell damage in human islets. Silencing of GPR183 in INS-1 cells decreased the expression of proinsulin genes, Pdx1, Mafa and impaired insulin secretion with a concomitant decrease in cAMP generation. Cultured INS-1 cells with 7α-25-DHC were associated with increased proliferation and expression of GPR183, INS2, PDX1, NeuroD, and INSR. In conclusion, the beneficial impact of GPR183 activation on ß-cell function makes it a potential therapeutic target to prevent or reverse ß-cell dysfunction.

ILC2 transfers to apolipoprotein E deficient mice reduce the lipid content of atherosclerotic lesions.

BACKGROUND: Expansion of type 2 innate lymphoid cells (ILC2s) in hypercholesterolaemic mice protects against atherosclerosis while different ILC2 subsets have been described (natural, inflammatory) based on their suppression of tumorigenicity 2 (ST2) and killer-cell lectin like receptor G1 (KLRG1) expression. The aim of the current study is to characterize the interleukin 25 (IL25)-induced splenic ILC2 population (Lin-CD45+IL17RB+ICOS+IL7raintermediate) and address its direct role in experimental atherosclerosis by its adoptive transfer to hypercholesterolaemic apolipoprotein E deficient (apoE-/-) mice. RESULTS: Immunomagnetically enriched, FACS-sorted ILC2s from the spleens of IL-25 treated apoE-/- mice were stained for KLRG1 and ST2 directly upon cell obtainment or in vitro cell expansion for flow cytometric analysis. IL25-induced splenic ILC2s express high levels of both KLRG1 and ST2. However, both markers are downregulated upon in vitro cell expansion. In vitro expanded splenic ILC2s were intraperitoneally transferred to apoE-/- recipients on high fat diet. ApoE-/- mice that received in vitro expanded splenic ILC2s had decreased lipid content in subvalvular heart and brachiocephalic artery (BCA) plaques accompanied by increased peritoneal B1 cells, activated eosinophils and alternatively activated macrophages (AAMs) as well as anti-phosphorylcholine (PC) immunoglobulin (Ig) M in plasma. CONCLUSIONS: With the current data we designate the IL25-induced ILC2 population to decrease the lipid content of atherosclerotic lesions in apoE-/- mice and we directly link the induction of B1 cells and the atheroprotective anti-PC IgM antibodies with ILC2s.

Cartilage Oligomeric Matrix Protein Associates With a Vulnerable Plaque Phenotype in Human Atherosclerotic Plaques.

Background and Purpose- Extracellular matrix proteins are important in atherosclerotic disease by influencing plaque stability and cellular behavior but also by regulating inflammation. COMP (cartilage oligomeric matrix protein) is present in healthy human arteries and expressed by smooth muscle cells. A recent study showed that transplantation of COMP-deficient bone marrow to apoE-/- mice increased atherosclerotic plaque formation, indicating a role for COMP also in bone marrow-derived cells. Despite the evidence of a role for COMP in murine atherosclerosis, knowledge is lacking about the role of COMP in human atherosclerotic disease. Methods- In the present study, we investigated if COMP was associated with a stable or a vulnerable human atherosclerotic plaque phenotype by analyzing 211 carotid plaques for COMP expression using immunohistochemistry. Results- Plaque area that stained positive for COMP was significantly larger in atherosclerotic plaques associated with symptoms (n=110) compared with asymptomatic plaques (n=101; 9.7% [4.7-14.3] versus 5.6% [2.8-9.8]; P=0.0002). COMP was positively associated with plaque lipids (r=0.32; P=0.000002) and CD68 cells (r=0.15; P=0.036) but was negatively associated with collagen (r=-0.16; P=0.024), elastin (r=-0.14; P=0.041), and smooth muscle cells (r=-0.25; P=0.0002). COMP was positively associated with CD163 (r=0.37; P=0.00000006), a scavenger receptor for hemoglobin/haptoglobin and a marker of Mhem macrophages, and with intraplaque hemorrhage, measured as glycophorin A staining (r=0.28; P=0.00006). Conclusions- The present study shows that COMP is associated to symptomatic carotid atherosclerosis, CD163-expressing cells, and a vulnerable atherosclerotic plaque phenotype in humans.

The functional impact of G protein-coupled receptor 142 (Gpr142) on pancreatic ß-cell in rodent.

We have recently shown that the G protein-coupled receptor 142 (GPR142) is expressed in both rodent and human pancreatic ß-cells. Herein, we investigated the cellular distribution of GPR142 within islets and the effects of selective agonists of GPR142 on glucose-stimulated insulin secretion (GSIS) in the mouse islets and INS-1832/13 cells. Double-immunostaining revealed that GPR142 immunoreactivity in islets mainly occurs in insulin-positive cells. Potentiation of GSIS by GPR142 activation was accompanied by increased cAMP content in INS-1832/13 cells. PKA/Epac inhibition markedly suppressed the effect of GPR142 activation on insulin release. Gpr142 knockdown (Gpr142-KD) in islets was accompanied by elevated release of MCP-1, IFNγ, and TNFα during culture period and abolished the modulatory effect of GPR142 activation on the GSIS. Gpr142-KD had no effect on Ffar1, Ffar2, or Ffar3 mRNA while reducing Gpr56 and increasing Tlr5 and Tlr7 mRNA expression. Gpr142-KD was associated with an increased expression of Chrebp, Txnip, RhoA, and mitochondrial Vdac1 concomitant with a reduced Pdx1, Pax6, and mitochondrial Vdac2 mRNA levels. Long-term exposure of INS-1832/13 cells to hyperglycemia reduced Gpr142 and Vdac2 while increased Chrebp, Txnip, and Vdac1 mRNA expression. GPR142 agonists or Bt2-cAMP counteracted this effect. Glucotoxicity-induced decrease of cell viability in Gpr142-KD INS-1 cells was not affected by GPR142-agonists while Bt2-cAMP prevented it. The results show the importance of Gpr142 in the maintenance of pancreatic ß-cell function in rodents and that GPR142 agonists potentiate GSIS by an action, which most likely is due to increased cellular generation of second messenger molecule cAMP.

Associations of Interleukin-5 With Plaque Development and Cardiovascular Events.

Experimental studies have suggested an atheroprotective role of interleukin (IL)-5 through the stimulation of natural immunoglobulin M antibody expression. In the present study we show that there are no associations between baseline levels of IL-5 and risk for development of coronary events or stroke during a 15.7 ± 6.3 years follow-up of 696 subjects randomly sampled from the Malmö Diet and Cancer study. However, presence of a plaque at the carotid bifurcation was associated with lower IL-5 and IL-5 deficiency resulted in increased plaque development at sites of oscillatory blood flow in Apoe -/- mice suggesting a protective role for IL-5 in plaque development.

Activation of imidazoline receptor I2, and improved pancreatic ß-cell function in human islets.

AIM: The impact of BL11282, an imidazoline receptor (NISCH) agonist, on potentiation of glucose-stimulated insulin secretion (GSIS) from isolated human non-diabetic (ND) and type 2 diabetic (T2D) islets was investigated. METHODS: Analysis of mRNA was performed by RNA-sequencing and qPCR. Insulin and cAMP by RIA and ELISA respectively. RESULTS: RNA-sequencing data revealed that NISCH is highly expressed in fat tissues, islets, liver and muscles, with eight detectable splice variants of transcripts in islets. NISCH had a positive correlation with GLP-1 (GLP1R) and GIP (GIPR) receptor transcripts. The expression of NISCH was confirmed by qPCR in human islets. NISCH and GLP1R were comparably higher expressed in mouse islets compared to human islets. GSIS was dose-dependently potentiated by BL11282 from incubated islets of ND and T2D human islet donors. The insulinotropic action of BL11282 was associated with increased cAMP. While the harmful effect of high glucose on reductive capacity of islet cells was enhanced by glibenclamide during long-term culture, it was counteracted by BL11282 or Bt2-cAMP. BL11282 also increased proliferation of INS-1 cells during long-time culture. CONCLUSION: Our data suggest that BL11282 potentiates GSIS by an action involving cAMP/PKA system and BL11282 could be an attractive insulinotropic and ß-cell protective agent.

Hyperglycemia does not affect tissue repair responses in shear stress-induced atherosclerotic plaques in ApoE-/- mice.

The mechanisms responsible for macrovascular complications in diabetes remain to be fully understood. Recent studies have identified impaired vascular repair as a possible cause of plaque vulnerability in diabetes. This notion is supported by observations of a reduced content of fibrous proteins and smooth muscle cell mitogens in carotid endarterectomy from diabetic patients along with findings of decreased circulating levels of endothelial progenitor cells. In the present study we used a diabetic mouse model to characterize how hyperglycemia affects arterial repair responses. We induced atherosclerotic plaque formation in ApoE-deficient (ApoE-/-) and heterozygous glucokinase knockout ApoE-deficient mice (ApoE-/- GK+/-) mice with a shear stress-modifying cast. There were no differences in cholesterol or triglyceride levels between the ApoE-/- and ApoE-/- GK+/- mice. Hyperglycemia did not affect the size of the formed atherosclerotic plaques, and no effects were seen on activation of cell proliferation, smooth muscle cell content or on the expression and localization of collagen, elastin and several other extracellular matrix proteins. The present study demonstrates that hyperglycemia per se has no significant effects on tissue repair processes in injured mouse carotid arteries, suggesting that other mechanisms are involved in diabetic plaque vulnerability.

Interleukin-25 (IL-25) has a protective role in atherosclerosis development in the aortic arch in mice.

Atherosclerosis is a chronic inflammatory disease characterized by the entrapment of apolipoprotein B-containing lipoproteins in the arterial intima, leading to local inflammation. T helper (Th) cell 1-mediated immune responses have been associated with atherosclerosis, and the cytokine interleukin-25 (IL-25 or IL-17E) has been reported to potentially regulate Th1 cell- and Th17 cell-related immune responses. In this study, we evaluated the effects of complete IL-25 deficiency or of a temporal IL-25 blockade on atherosclerosis development in apolipoprotein E-deficient (Apoe-/-) mice. Mice deficient in both apolipoprotein E and IL-25 (Apoe-/-/IL-25-/-) had more Th1 cells in the spleen, along with elevated plasma levels of IL-17 and an increased release of splenic interferon-γ (INF-γ). In support of this observation, a 4-week-long treatment of young Apoe-/- mice (at 10-14 weeks of age) with an IL-25-blocking antibody increased the release of Th1/Th17-associated cytokines in the spleen. In both mouse models, these findings were associated with increased atherosclerotic plaque formation in the aortic arch. We conclude that complete IL-25 deficiency and a temporal IL-25 blockade during early plaque development aggravate atherosclerosis development in the aortic arch of Apoe-/- mice, accompanied by an increase in Th1/Th17-mediated immune responses. Our finding that endogenous IL-25 has an atheroprotective role in the murine aortic arch has potential implications for atherosclerosis development and management in humans.

ß-Sarcoglycan Deficiency Reduces Atherosclerotic Plaque Development in ApoE-Null Mice.

BACKGROUND: Smooth muscle cells are important for atherosclerotic plaque stability. Their proper ability to communicate with the extracellular matrix is crucial for maintaining the correct tissue integrity. In this study, we have investigated the role of ß-sarcoglycan within the matrix-binding dystrophin-glycoprotein complex in the development of atherosclerosis. RESULTS: Atherosclerotic plaque development was significantly reduced in ApoE-deficient mice lacking ß-sarcoglycan, and their plaques contained an increase in differentiated smooth muscle cells. ApoE-deficient mice lacking ß-sarcoglycan showed a reduction in ovarian adipose tissue and adipocyte size, while the total weight of the animals was not significantly different. Western blot analysis of adipose tissues showed a decreased activation of protein kinase B, while that of AMP-activated kinase was increased in mice lacking ß-sarcoglycan. Analysis of plasma in ß-sarcoglycan-deficient mice revealed reduced levels of leptin, adiponectin, insulin, cholesterol, and triglycerides but increased levels of IL-6, IL-17, and TNF-α. CONCLUSIONS: Our results indicate that the dystrophin-glycoprotein complex and ß-sarcoglycan can affect the atherosclerotic process. Furthermore, the results show the effects of ß-sarcoglycan deficiency on adipose tissue and lipid metabolism, which may also have contributed to the atherosclerotic plaque reduction.

ADAMTS-7 is associated with a high-risk plaque phenotype in human atherosclerosis.

Several large-scale genome-wide association studies have identified single-nucleotide polymorphisms in the genomic region of A Disintegrin And Metalloproteinase with ThromboSpondin type 1 repeats (ADAMTS)-7 and associations to coronary artery disease. Experimental studies have provided evidence for a functional role of ADAMTS-7 in both injury-induced vascular neointima formation and development of atherosclerotic lesions. However, whether ADAMTS-7 is associated with a specific plaque phenotype in humans has not been investigated. Carotid plaques (n = 206) from patients with and without cerebrovascular symptoms were analyzed for expression of ADAMTS-7 by immunohistochemistry and correlated to components associated with plaque vulnerability. Plaques from symptomatic patients showed increased levels of ADAMTS-7 compared with lesions from asymptomatic patients. High levels of ADAMTS-7 correlated with high levels of CD68-staining and lipid content, but with low smooth muscle cell and collagen content, which together are characteristics of a vulnerable plaque phenotype. ADAMTS-7 levels above median were associated with increased risk for postoperative cardiovascular events. Our data show that ADAMTS-7 is associated with a vulnerable plaque phenotype in human carotid lesions. These data support previous observations of a potential proatherogenic role of ADAMTS-7.

Adhesion G Protein-Coupled Receptor G1 (ADGRG1/GPR56) and Pancreatic ß-Cell Function.

CONTEXT: Adhesion G protein-coupled receptor (GPCR)-G1 (ADGRG1) is the most abundant GPCR in human pancreatic islets, but its role in islet function is unclear. OBJECTIVE: Investigate how ADGRG1 expression and activation by its ligand, collagen III, impacts ß-cell function in normal and type 2 diabetic (T2D) islets. DESIGN: Genes associated with the ADGRG1 in human islets was probed by RNA-sequencing of human pancreatic islet isolated from cadaveric donors, followed by functional studies on ß-cell proliferation, apoptosis, and insulin secretion in human and mouse islets and in INS-1 cells. MAIN OUTCOME MEASURES: Changes in ß-cell gene expression, proliferation, apoptosis, and insulin secretion were quantified by RNA-sequencing, qPCR, Thymidine incorporation, Western blotting, and RIA, respectively. RESULTS: ADGRG1 is the most abundant GPCR mRNA in both human and mouse islets, and its expression in human islets strongly correlates with genes important for ß-cell function and T2D risk. The expression of ADGRG1 was reduced in islets of T2D donors, in db/db mouse islets, and in isolated human islets exposed to chronic hyperglycemia. Beneficial effects of collagen type III on ß-cell function via activation of the cAMP/protein kinase A pathway, suppression of RhoA and caspase-3 activity, increased ß-cell viability, and proliferation were abolished when ADGRG1 was down-regulated in ß-cells. CONCLUSIONS: We demonstrate a mechanistic link between ADGRG1 expression and ß-cell function. Pharmacological agents that promote expression or activation of the ADGRG1 receptor may represent a novel approach for the treatment of T2D.

Sphingolipids Contribute to Human Atherosclerotic Plaque Inflammation.

OBJECTIVE: Lipids are central to the development of atherosclerotic plaques. Specifically, which lipids are culprits remains controversial, and promising targets have failed in clinical studies. Sphingolipids are bioactive lipids present in atherosclerotic plaques, and they have been suggested to have both proatherogenic and antiatherogenic. However, the biological effects of these lipids remain unknown in the human atherosclerotic plaque. The aim of this study was to assess plaque levels of sphingolipids and investigate their potential association with and contribution to plaque vulnerability. APPROACH AND RESULTS: Glucosylceramide, lactosylceramide, ceramide, dihydroceramide, sphingomyelin, and sphingosine-1-phosphate were analyzed in homogenates from 200 human carotid plaques using mass spectrometry. Inflammatory activity was determined by analyzing plaque levels of cytokines and plaque histology. Caspase-3 was analyzed by ELISA technique. Expression of regulatory enzymes was analyzed with RNA sequencing. Human coronary artery smooth muscle cells were used to analyze the potential role of the 6 sphingolipids as inducers of plaque inflammation and cellular apoptosis in vitro. All sphingolipids were increased in plaques associated with symptoms and correlated with inflammatory cytokines. All sphingolipids, except sphingosine-1-phosphate, also correlated with histological markers of plaque instability. Lactosylceramide, ceramide, sphingomyelin, and sphingosine-1-phosphate correlated with caspase-3 activity. In vitro experiments revealed that glucosylceramide, lactosylceramide, and ceramide induced cellular apoptosis. All analyzed sphingolipids induced an inflammatory response in human coronary artery smooth muscle cells. CONCLUSIONS: This study shows for the first time that sphingolipids and particularly glucosylceramide are associated with and are possible inducers of plaque inflammation and instability, pointing to sphingolipid metabolic pathways as possible novel therapeutic targets.