T cell-intrinsic ASC critically promotes T(H)17-mediated experimental autoimmune encephalomyelitis.

Interleukin 1ß (IL-1ß) is critical for the in vivo survival, expansion and effector function of IL-17-producing helper T (T(H)17) cells during autoimmune responses, including experimental autoimmune encephalomyelitis (EAE). However, the spatiotemporal role and cellular source of IL-1ß during EAE pathogenesis are poorly defined. In the present study, we uncovered a T cell-intrinsic inflammasome that drives IL-1ß production during T(H)17-mediated EAE pathogenesis. Activation of T cell antigen receptors induced expression of pro-IL-1ß, whereas ATP stimulation triggered T cell production of IL-1ß via ASC-NLRP3-dependent caspase-8 activation. IL-1R was detected on T(H)17 cells but not on type 1 helper T (T(H)1) cells, and ATP-treated T(H)17 cells showed enhanced survival compared with ATP-treated T(H)1 cells, suggesting autocrine action of T(H)17-derived IL-1ß. Together these data reveal a critical role for IL-1ß produced by a T(H)17 cell-intrinsic ASC-NLRP3-caspase-8 inflammasome during inflammation of the central nervous system.

Reduced hypoglycaemia using liver-targeted insulin in individuals with type 1 diabetes.

AIM: To investigate whether an increased bolus: basal insulin ratio (BBR) with liver-targeted bolus insulin (BoI) would increase BoI use and decrease hypoglycaemic events (HEv). PATIENT POPULATION AND METHODS: We enrolled 52 persons (HbA1c 6.9% ± 0.12%, mean ± SEM) with type 1 diabetes using multiple daily injections. Hepatic-directed vesicle (HDV) was used to deliver 1% of peripheral injected BoI to the liver. A 90-day run-in period was used to introduce subjects to unblinded continuous glucose monitoring and optimize standard basal insulin (BaI) (degludec) and BoI (lispro) dosing. At 90 days, BoI was changed to HDV-insulin lispro and subjects were randomized to an immediate 10% or 40% decrease in BaI dose. RESULTS: At 90 days postrandomization, total insulin dosing was increased by ~7% in both cohorts. The -10% and -40% BaI cohorts were on 7.7% and 13% greater BoI with 6.9% and 30% (P = .02) increases in BBR, respectively. Compared with baseline at randomization, nocturnal level 2 HEv were reduced by 21% and 43%, with 54% and 59% reductions in patient-reported HEv in the -10% and -40% BaI cohorts, respectively. CONCLUSIONS: Our study shows that liver-targeted BoI safely decreases HEv and symptoms without compromising glucose control. We further show that with initiation of liver-targeted BoI, the BBR can be safely increased by significantly lowering BaI dosing, leading to greater BoI usage.

Development and Internal Validation of A Prediction Tool To Assist Clinicians Selecting Second-Line Therapy Following Metformin Monotherapy For Type 2 Diabetes.

OBJECTIVE: Adults with type 2 diabetes (T2D) face increased risk of many long-term adverse outcomes. While managing patients with T2D, clinicians are challenged to stay informed regarding all new therapies and must consider potential risks and benefits resultant to their use. Metformin (MET) is typically prescribed as first-line therapy, but a second line is often needed, given MET can be insufficient for maintaining long-term glycemic control. Our objective was to develop a predictive decision-making tool to help clinicians use an outcome-based approach to select second-line therapies for patients when MET monotherapy is insufficient for glycemic control. METHODS: Electronic health records of 19 277 adults with T2D on MET monotherapy and ≥3 months of either GLP-1RA, DPP-4i, Insulin, SGLT-2i, SFU, or TZD therapy were reviewed at Cleveland Clinic from patient visits occurring between 2005 and 2019. Separate models were developed to predict likelihood of each main outcome measure (stroke, myocardial infarction, worsening hypertension, renal failure, and death). Discrimination and calibration were assessed with bootstrapping. RESULTS: The median follow-up time for those without an event was 3.6 years (interquartile range 1.9, 6.3). Model discrimination ability was evaluated by concordance indices (goodness of fit metric with values ranging between 0 and 1: 1 indicates perfect discrimination ability; 0.5 reflects same discrimination ability as chance) demonstrating strong discrimination ability, with concordance index values for outcomes as follows: myocardial infarction (0.786), stroke (0.805), worsening hypertension (0.855), renal failure (0.808), and death (0.827). CONCLUSION: A decision-making tool has been developed that may afford clinicians a more objective and individualized approach to choosing a second-line therapy to control glycemia for persons with T2D.

Caspase-8 as an Effector and Regulator of NLRP3 Inflammasome Signaling.

We recently described the induction of noncanonical IL-1ß processing via caspase-8 recruited to ripoptosome signaling platforms in myeloid leukocytes. Here, we demonstrate that activated NLRP3·ASC inflammasomes recruit caspase-8 to drive IL-1ß processing in murine bone marrow-derived dendritic cells (BMDC) independent of caspase-1 and -11. Sustained stimulation (>2 h) of LPS-primed caspase-1-deficient (Casp1/11(-/-)) BMDC with the canonical NLRP3 inflammasome agonist nigericin results in release of bioactive IL-1ß in conjunction with robust caspase-8 activation. This IL-1ß processing and caspase-8 activation do not proceed in Nlrp3(-/-) or Asc(-/-) BMDC and are suppressed by pharmacological inhibition of caspase-8, indicating that caspase-8 can act as a direct IL-1ß-converting enzyme during NLRP3 inflammasome activation. In contrast to the rapid caspase-1-mediated death of wild type (WT) BMDC via NLRP3-dependent pyroptosis, nigericin-stimulated Casp1/11(-/-) BMDC exhibit markedly delayed cell death via NLRP3-dependent apoptosis. Biochemical analyses of WT and Casp1/11(-/-) BMDC indicated that caspase-8 is proteolytically processed within detergent-insoluble ASC-enriched protein complexes prior to extracellular export during nigericin treatment. Although nigericin-stimulated caspase-1 activation and activity are only modestly attenuated in caspase-8-deficient (Casp8(-/-)Rip3(-/-)) BMDC, these cells do not exhibit the rapid loss of viability of WT cells. These results support a contribution of caspase-8 to both IL-1ß production and regulated death signaling via NLRP3 inflammasomes. In the absence of caspase-1, NLRP3 inflammasomes directly utilize caspase-8 as both a pro-apoptotic initiator and major IL-1ß-converting protease. In the presence of caspase-1, caspase-8 acts as a positive modulator of the NLRP3-dependent caspase-1 signaling cascades that drive both IL-1ß production and pyroptotic death.

Proapoptotic chemotherapeutic drugs induce noncanonical processing and release of IL-1ß via caspase-8 in dendritic cells.

The identification of noncanonical (caspase-1-independent) pathways for IL-1ß production has unveiled an intricate interplay between inflammatory and death-inducing signaling platforms. We found a heretofore unappreciated role for caspase-8 as a major pathway for IL-1ß processing and release in murine bone marrow-derived dendritic cells (BMDC) costimulated with TLR4 agonists and proapoptotic chemotherapeutic agents such as doxorubicin (Dox) or staurosporine (STS). The ability of Dox to stimulate release of mature (17-kDa) IL-1ß was nearly equivalent in wild-type (WT) BMDC, Casp1(-/-)Casp11(-/-) BMDC, WT BMDC treated with the caspase-1 inhibitor YVAD, and BMDC lacking the inflammasome regulators ASC, NLRP3, or NLRC4. Notably, Dox-induced production of mature IL-1ß was temporally correlated with caspase-8 activation in WT cells and greatly suppressed in Casp8(-/-)Rip3(-/-) or Trif(-/-) BMDC, as well as in WT BMDC treated with the caspase-8 inhibitor, IETD. Similarly, STS stimulated robust IL-1ß processing and release in Casp1(-/-)Casp11(-/-) BMDC that was IETD sensitive. These data suggest that TLR4 induces assembly of caspase-8-based signaling complexes that become licensed as IL-1ß-converting enzymes in response to Dox and STS. The responses were temporally correlated with downregulation of cellular inhibitor of apoptosis protein 1, suggesting suppressive roles for this and likely other inhibitor of apoptosis proteins on the stability and/or proteolytic activity of the caspase-8 platforms. Thus, proapoptotic chemotherapeutic agents stimulate the caspase-8-mediated processing and release of IL-1ß, implicating direct effects of such drugs on a noncanonical inflammatory cascade that may modulate immune responses in tumor microenvironments.

3-point major cardiovascular event outcome for patients with T2D treated with dipeptidyl peptidase-4 inhibitor or glucagon-like peptide-1 receptor agonist in addition to metformin monotherapy.

BACKGROUND: The global incidence of type 2 diabetes (T2D) continues to increase annually, and persons with T2D typically require regular changes in pharmacologic invention for achieving glycemic targets. Healthcare providers must consider multiple factors when selecting a 2nd line. This retrospective cohort study evaluates impact of two common anti-diabetes medication classes (dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 receptor agonists) on the well-known composite 3-point major cardiovascular events outcome (3P-MACE, comprised of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke). No significant impact was found. Persons with T2D face increased risks of many adverse cardiovascular outcomes. This study duplicated common inclusion and exclusion criteria to create an observational cohort from a large healthcare system's electronic health records for testing DPP-4i and GLP-1RA against each other to evaluate impact on likelihood to develop 3P-MACE. METHODS: The statistical model and analyses were based on a cohort of 5,518 adult patients with T2D who were prescribed metformin and either DPP-4i or GLP-1RA to control glycemia during clinic visits between January 2005 and September 2019. A Cox proportional hazards model was developed from the cohort to predict the 3P-MACE endpoint. RESULTS: The model did not show a meaningful difference in likelihood of developing the 3P-MACE outcome between patients treated with DPP-4i compared to patients treated with GLP-1RA. CONCLUSIONS: Prior history of cardiovascular disease (CVD) did not impact this small difference between the two classes of drug.

Modification of ß-Defensin-2 by Dicarbonyls Methylglyoxal and Glyoxal Inhibits Antibacterial and Chemotactic Function In Vitro.

BACKGROUND: Beta-defensins (hBDs) provide antimicrobial and chemotactic defense against bacterial, viral and fungal infections. Human ß-defensin-2 (hBD-2) acts against gram-negative bacteria and chemoattracts immature dendritic cells, thus regulating innate and adaptive immunity. Immunosuppression due to hyperglycemia underlies chronic infection in Type 2 diabetes. Hyperglycemia also elevates production of dicarbonyls methylgloxal (MGO) and glyoxal (GO). METHODS: The effect of dicarbonyl on defensin peptide structure was tested by exposing recombinant hBD-2 (rhBD-2) to MGO or GO with subsequent analysis by MALDI-TOF MS and LC/MS/MS. Antimicrobial function of untreated rhBD-2 vs. rhBD-2 exposed to dicarbonyl against strains of both gram-negative and gram-positive bacteria in culture was determined by radial diffusion assay. The effect of dicarbonyl on rhBD-2 chemotactic function was determined by chemotaxis assay in CEM-SS cells. RESULTS: MGO or GO in vitro irreversibly adducts to the rhBD-2 peptide, and significantly reduces antimicrobial and chemotactic functions. Adducts derive from two arginine residues, Arg22 and Arg23 near the C-terminus, and the N-terminal glycine (Gly1). We show by radial diffusion testing on gram-negative E. coli and P. aeruginosa, and gram-positive S. aureus, and a chemotaxis assay for CEM-SS cells, that antimicrobial activity and chemotactic function of rhBD-2 are significantly reduced by MGO. CONCLUSIONS: Dicarbonyl modification of cationic antimicrobial peptides represents a potential link between hyperglycemia and the clinical manifestation of increased susceptibility to infection, protracted wound healing, and chronic inflammation in undiagnosed and uncontrolled Type 2 diabetes.

Stealth filaments: Polymer chain length and conformation affect the in vivo fate of PEGylated potato virus X.

Nanoparticles hold great promise for delivering medical cargos to cancerous tissues to enhance contrast and sensitivity of imaging agents or to increase specificity and efficacy of therapeutics. A growing body of data suggests that nanoparticle shape, in combination with surface chemistry, affects their in vivo fates, with elongated filaments showing enhanced tumor targeting and tissue penetration, while promoting immune evasion. The synthesis of high aspect ratio filamentous materials at the nanoscale remains challenging using synthetic routes; therefore we turned toward nature's materials, developing and studying the filamentous structures formed by the plant virus potato virus X (PVX). We recently demonstrated that PVX shows enhanced tumor homing in various preclinical models. Like other nanoparticle systems, the proteinaceous platform is cleared from circulation and tissues by the mononuclear phagocyte system (MPS). To increase bioavailability we set out to develop PEGylated stealth filaments and evaluate the effects of PEG chain length and conformation on pharmacokinetics, biodistribution, as well as potential immune and inflammatory responses. We demonstrate that PEGylation effectively reduces immune recognition while increasing pharmacokinetic profiles. Stealth filaments show reduced interaction with cells of the MPS; the protein:polymer hybrids are cleared from the body tissues within hours to days indicating biodegradability and biocompatibility. Tissue compatibility is indicated with no apparent inflammatory signaling in vivo. Tailoring PEG chain length and conformation (brush vs. mushroom) allows tuning of the pharmacokinetics, yielding long-circulating stealth filaments for applications in nanomedicine.