The Coagulation and Immune Systems are Directly Linked through the Activation of Interleukin-1α by Thrombin

Ancient organisms have a combined coagulation and immune system, and although links between inflammation and haemostasis exist in mammals, they are indirect and slower to act. Here we investigated direct links between mammalian immune and coagulation systems by examining cytokine proproteins for potential thrombin protease consensus sites. We found that interleukin (IL)-1α is directly activated by thrombin. Thrombin cleaved pro-IL-1α at a site perfectly conserved across disparate species, indicating functional importance. Surface pro-IL-1α on macrophages and activated platelets was cleaved and activated by thrombin, while tissue factor, a potent thrombin activator, colocalised with pro-IL-1α in the epidermis. Mice bearing a mutation in the IL-1α thrombin cleavage site (R114Q) exhibited defects in efficient wound healing and rapid thrombopoiesis after acute platelet loss. Thrombin-cleaved IL-1α was detected in humans during sepsis, pointing to the relevance of this pathway for normal physiology and the pathogenesis of inflammatory and thrombotic diseases.This work was funded by British Heart Foundation Grants FS/09/005/26845, FS/13/3/30038, FS/18/19/33371 and RG/16/8/32388 to MC, RG/13/14/30314 to MB, the BHF Cambridge Centre for Research Excellence RE/13/6/30180, the Oxbridge BHF Regenerative Medicine Centre RM/13/3/30159, and the Cambridge NIHR Biomedical Research Centre

Vascular Smooth Muscle Cell Senescence Promotes Atherosclerosis and Features of Plaque Vulnerability.

BACKGROUND: Although vascular smooth muscle cell (VSMC) proliferation is implicated in atherogenesis, VSMCs in advanced plaques and cultured from plaques show evidence of VSMC senescence and DNA damage. In particular, plaque VSMCs show shortening of telomeres, which can directly induce senescence. Senescence can have multiple effects on plaque development and morphology; however, the consequences of VSMC senescence or the mechanisms underlying VSMC senescence in atherosclerosis are mostly unknown. METHODS AND RESULTS: We examined the expression of proteins that protect telomeres in VSMCs derived from human plaques and normal vessels. Plaque VSMCs showed reduced expression and telomere binding of telomeric repeat-binding factor-2 (TRF2), associated with increased DNA damage. TRF2 expression was regulated by p53-dependent degradation of the TRF2 protein. To examine the functional consequences of loss of TRF2, we expressed TRF2 or a TRF2 functional mutant (T188A) as either gain- or loss-of-function studies in vitro and in apolipoprotein E(-/-) mice. TRF2 overexpression bypassed senescence, reduced DNA damage, and accelerated DNA repair, whereas TRF2(188A) showed opposite effects. Transgenic mice expressing VSMC-specific TRF2(T188A) showed increased atherosclerosis and necrotic core formation in vivo, whereas VSMC-specific TRF2 increased the relative fibrous cap and decreased necrotic core areas. TRF2 protected against atherosclerosis independent of secretion of senescence-associated cytokines. CONCLUSIONS: We conclude that plaque VSMC senescence in atherosclerosis is associated with loss of TRF2. VSMC senes cence promotes both atherosclerosis and features of plaque vulnerability, identifying prevention of senescence as a potential target for intervention

Tele-education model for primary care providers to advance diabetes equity: Findings from Project ECHO Diabetes

IntroductionIn the US, many individuals with diabetes do not have consistent access to endocrinologists and therefore rely on primary care providers (PCPs) for their diabetes management. Project ECHO (Extension for Community Healthcare Outcomes) Diabetes, a tele-education model, was developed to empower PCPs to independently manage diabetes, including education on diabetes technology initiation and use, to bridge disparities in diabetes.MethodsPCPs (n=116) who participated in Project ECHO Diabetes and completed pre- and post-intervention surveys were included in this analysis. The survey was administered in California and Florida to participating PCPs via REDCap and paper surveys. This survey aimed to evaluate practice demographics, protocols with adult and pediatric T1D management, challenges, resources, and provider knowledge and confidence in diabetes management. Differences and statistical significance in pre- and post-intervention responses were evaluated via McNemar’s tests.ResultsPCPs reported improvement in all domains of diabetes education and management. From baseline, PCPs reported improvement in their confidence to serve as the T1D provider for their community (pre vs post: 43.8% vs 68.8%, p=0.005), manage insulin therapy (pre vs post: 62.8% vs 84.3%, p=0.002), and identify symptoms of diabetes distress (pre vs post: 62.8% vs 84.3%, p=0.002) post-intervention. Compared to pre-intervention, providers reported significant improvement in their confidence in all aspects of diabetes technology including prescribing technology (41.2% vs 68.6%, p=0.001), managing insulin pumps (41.2% vs 68.6%, p=0.001) and hybrid closed loop (10.2% vs 26.5%, p=0.033), and interpreting sensor data (41.2% vs 68.6%, p=0.001) post-intervention.DiscussionPCPs who participated in Project ECHO Diabetes reported increased confidence in diabetes management, with notable improvement in their ability to prescribe, manage, and troubleshoot diabetes technology. These data support the use of tele-education of PCPs to increase confidence in diabetes technology management as a feasible strategy to advance equity in diabetes management and outcomes

Marginal zone B cells control the response of follicular helper T cells to a high-cholesterol diet

Splenic marginal zone B (MZB) cells, positioned at the interface between circulating blood and lymphoid tissue, detect and respond to blood-borne antigens. Here we show that MZB cells in mice activate a homeostatic program in response to a high-cholesterol diet (HCD) and regulate both the differentiation and accumulation of T follicular helper (TFH) cells. Feeding mice an HCD resulted in upregulated MZB cell surface expression of the immunoregulatory ligand PDL1 in an ATF3-dependent manner and increased the interaction between MZB cells and pre-TFH cells, leading to PDL1-mediated suppression of TFH cell motility, alteration of TFH cell differentiation, reduced TFH abundance and suppression of the proatherogenic TFH response. Our findings reveal a previously unsuspected role for MZB cells in controlling the TFH–germinal center response to a cholesterol-rich diet and uncover a PDL1-dependent mechanism through which MZB cells use their innate immune properties to limit an exaggerated adaptive immune response.This work was supported by BHF grant no. PG/15/76/31756, BHF grant no. PG/13/73/30466, ERC grant no. 2891164 and EC FP7 VIA grant no. HEALTH-F4- 2013-603131 to Z.M. and by SAF2013-45543-R from the Spanish Ministry of Economy and Competitiveness (MINECO) to J.L.d.l.P. M.N. was first supported by a Sara Borrell grant (CD09/00452) from the Instituto Nacional de Salud Carlos III (Spain) and then by a 2-year BHF Project Grant. M.N. has also received funding from the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme (FP7/2007-2013) under REA grant agreement no. 608765. The Wellcome Trust supported the Cambridge Mouse Biochemistry Laboratory

Effects of DNA damage in smooth muscle cells in atherosclerosis

Rationale: DNA damage and the DNA damage response (DDR) have been identified in human atherosclerosis, including in vascular smooth muscle cells (VSMCs). However, although double strand breaks (DSBs) are hypothesized to promote plaque progression and instability, in part by promoting cell senescence, apoptosis and inflammation, the direct effects of DSBs in VSMCs seen in atherogenesis are unknown. Objective: To determine the presence and effect of endogenous levels of DSBs in VSMCs on atherosclerosis. Methods and Results: Human atherosclerotic plaque VSMCs showed increased expression of multiple DDR proteins in vitro and in vivo, particularly the MRN complex (MRE11, RAD50, NBS1) that senses DSB repair. Oxidative stress-induced DSBs were increased in plaque VSMCs, but DSB repair was maintained. To determine the effect of DSBs on atherosclerosis, we generated two novel transgenic mice lines expressing NBS1 or C-terminal deleted NBS1 only in VSMCs, and crossed them with ApoE-/- mice. SM22α-NBS1/ApoE-/- VSMCs showed enhanced DSB repair and decreased growth arrest and apoptosis, whereas SM22α-(ΔC)NBS1/ApoE-/- VSMCs showed reduced DSB repair and increased growth arrest and apoptosis. Accelerating or retarding DSB repair did not affect atherosclerosis extent or composition. However, VSMC DNA damage reduced relative fibrous cap areas, whereas accelerating DSB repair increased cap area and VSMC content. Conclusions: Human atherosclerotic plaque VSMCs show increased DNA damage including DSBs and DDR activation. VSMC DNA damage has minimal effects on atherogenesis, but alters plaque phenotype inhibiting fibrous cap areas in advanced lesions. Inhibiting DNA damage in atherosclerosis may be a novel target to promote plaque stability

Thrombin activated Interleukin-1α drives atherogenesis, but also promotes VSMC proliferation and collagen production.

AIMS: Atherosclerosis is driven by multiple processes across multiple body systems. For example, the innate immune system drives both atherogenesis and plaque rupture via inflammation, while coronary artery-occluding thrombi formed by the coagulation system cause myocardial infarction and death. However, the interplay between these systems during atherogenesis is understudied. We recently showed that coagulation and immunity are fundamentally linked by the activation of Interleukin-1α (IL-1α) by thrombin, and generated a novel knock-in mouse in which thrombin cannot activate endogenous IL-1α (IL-1αTM). METHODS AND RESULTS: Here, we show significantly reduced atherosclerotic plaque formation in IL-1αTM/Apoe-/- mice compared to Apoe-/- and reduced T cell infiltration. However, IL-1αTM/Apoe-/- plaques have reduced vascular smooth muscle cells (VSMCs), collagen and fibrous caps, indicative of a more unstable phenotype. Interestingly, the reduced atherogenesis seen with thrombin inhibition was absent in IL-1αTM/Apoe-/- mice, suggesting that thrombin inhibitors can affect atherosclerosis via reduced IL-1α activation. Finally, bone marrow chimeras show that thrombin activated IL-1α is derived from both vessel wall and myeloid cells. CONCLUSIONS: Together, we reveal that the atherogenic effect of ongoing coagulation is, in part, mediated via thrombin cleavage of IL-1α. This highlights the importance of interplay between systems during disease and the potential for therapeutically targeting IL-1α and/or thrombin, but also forewarns that IL-1 may have a role in plaque stabilisation.This work was funded by British Heart Foundation Grants FS/13/3/30038, FS/18/19/33371, RG/16/8/32388 and SP/F/22/150038 to MC; the BHF Cambridge Centre for Research Excellence RE/13/6/30180 and RE/18/1/34212; and the Cambridge NIHR Biomedical Research Centre

COVID-19 impacts and inequities among underserved communities with diabetes

Background: People with diabetes have higher COVID-19 morbidity and mortality. These risks are amplified for underserved communities including racial/ethnic minorities and people with lower socioeconomic status. However, limited research has examined COVID-19 outcomes specifically affecting underserved communities with diabetes. Methods: From November 2021 to July 2022, adults with insulin-requiring diabetes at federally qualified health centers in Florida and California (n = 450) completed surveys examining COVID-19 outcomes and demographics. Surveys assessed COVID-19 severity, vaccination uptake, mask-wearing habits, income changes, and healthcare access changes. Surveys also included the full Coronavirus Anxiety Scale (CAS-19). Descriptive statistics were computed for all outcomes. Between-group comparisons for state and race/ethnicity were evaluated via Chi-Squared, Fisher’s Exact, Cochran-Mantel-Haenszel, One-Way ANOVA, and t-tests. Logistic regression determined factors associated with COVID-19 vaccination uptake. Data were self-reported and analyzed cross-sectionally. Results: Overall, 29.7 % reported contracting COVID-19; of those, 45.3 % sought care or were hospitalized. Most (81.3 %) received ≥ 1 vaccine. Hispanics had the highest vaccination rate (91.1 %); Non-Hispanic Blacks (NHBs) had the lowest (73.9 %; p =.0281). Hispanics had 4.63x greater vaccination odds than Non-Hispanic Whites ([NHWs]; 95 % CI = [1.81, 11.89]). NHWs least often wore masks (18.8 %; p <.001). Participants reported pandemic-related healthcare changes (62 %) and higher costs of diabetes medications (41 %). Income loss was more frequent in Florida (76 %; p <.001). NHBs most frequently reported “severe” income loss (26.4 %; p =.0124). Loss of health insurance was more common among NHBs (13.3 %; p =.0416) and in Florida (9.7 %; p =.039). COVID-19 anxiety was highest among NHBs and Hispanics (IQR = [0.0, 3.0]; p =.0232) and in Florida (IQR = [0.0, 2.0]; p =.0435). Conclusions: Underserved communities with diabetes had high COVID-19 vaccine uptake but experienced significant COVID-19-related physical, psychosocial, and financial impacts. NHBs and those in Florida had worse outcomes than other racial/ethnic groups and those in California. Further research, interventions, and policy changes are needed to promote health equity for this population