Mini tryptophanyl-tRNA synthetase is required for a synthetic phenotype in vascular smooth muscle cells induced by IFN-γ-mediated β2-adrenoceptor signaling

Sodium-glucose cotransporter protein 2 inhibition, plasma proteins, and ischemic stroke: A mediation Mendelian randomization and colocalization study

PURPOSE

To determine the effect of the sodium-glucose cotransporter protein 2 (SGLT2) inhibition on ischemic stroke (IS) and investigate the circulating proteins that mediate the effects of SGLT2 inhibition on IS.

METHODS

The effects of SGLT2 inhibition on IS were evaluated using two-sample Mendelian randomization (MR) analyses. The 4,907 circulating proteins from the plasma proteome were assessed to identify potential mediators. Sensitivity, colocalization, and external validation analyses were conducted to validate critical findings. MR analyses were also used to evaluate the associations of SGLT2 inhibition with magnetic resonance imaging (MRI)-based biomarkers and functional prognoses post-IS.

RESULTS

SGLT2 inhibition was significantly associated with decreased risks of IS (odds ratio (OR): 0.39, 95 % confidence interval (CI): 0.25-0.61, p = 3.53 × 10-5) and cardioembolic stroke (OR: 0.16, 95 % CI: 0.07-0.37, p = 1.82 × 10-5); the effect of SGLT2 inhibition on IS was indirectly mediated through pathways involving tryptophanyl-transfer RNA synthetase (WARS) (β:0.08, 95 % CI:0.15 - -0.01, p = 0.034) and matrix metalloproteinase 12 (MMP12) (β:0.06, 95 % CI:0.12 - -0.01, p = 0.016), with mediation proportions of 8.2 % and 6.8 %, respectively. The external validation confirmed the WARS mediating effect. In addition, the sensitivity and colocalization analyses and MR analyses of MRI biomarker-based and functional prognostic outcomes supported these results.

CONCLUSION

In this study, we demonstrated from a genetic perspective that SGLT2 inhibitors prevent the development of IS and improve functional prognostic outcomes and brain microstructural integrity. WARS and MMP12 may act as potential mediators, presenting a novel approach for IS intervention.

Enhanced feature matching in single-cell proteomics characterizes IFN-γ response and co-existence of cell states

Proteome analysis by data-independent acquisition (DIA) has become a powerful approach to obtain deep proteome coverage, and has gained recent traction for label-free analysis of single cells. However, optimal experimental design for DIA-based single-cell proteomics has not been fully explored, and performance metrics of subsequent data analysis tools remain to be evaluated. Therefore, we here formalize and comprehensively evaluate a DIA data analysis strategy that exploits the co-analysis of low-input samples with a so-called matching enhancer (ME) of higher input, to increase sensitivity, proteome coverage, and data completeness. We assess the matching specificity of DIA-ME by a two-proteome model, and demonstrate that false discovery and false transfer are maintained at low levels when using DIA-NN software, while preserving quantification accuracy. We apply DIA-ME to investigate the proteome response of U-2 OS cells to interferon gamma (IFN-γ) in single cells, and recapitulate the time-resolved induction of IFN-γ response proteins as observed in bulk material. Moreover, we uncover co- and anti-correlating patterns of protein expression within the same cell, indicating mutually exclusive protein modules and the co-existence of different cell states. Collectively our data show that DIA-ME is a powerful, scalable, and easy-to-implement strategy for single-cell proteomics.

Effects of vildagliptin on wound healing and markers of inflammation in patients with type 2 diabetic foot ulcer: a prospective, randomized, double-blind, placebo-controlled, single-center study

INTRODUCTION

Diabetic foot ulcers (DFU) are one of the leading long-term complications experienced by patients with diabetes. Dipeptidyl Peptidase 4 inhibitors (DPP4is) are a class of antihyperglycemic medications prescribed to patients with diabetes to manage glycaemic control. DPP4is may also have a beneficial effect on DFU healing. This study aimed to determine vildagliptin's effect on inflammatory markers and wound healing.

TRIAL DESIGN

Prospective, randomized, double-blind, placebo-controlled, single-center study.

METHODS

Equal number of participants were randomized into the treatment and placebo groups. The treatment was for 12 weeks, during which the participants had regular visits to the podiatrist, who monitored their DFU sizes using 3D camera, and blood samples were taken at baseline, six weeks, and 12 weeks during the study for measurement of inflammatory markers. In addition, demographic characteristics, co-morbidities, DFU risk factors, and DFU wound parameters were recorded.

RESULTS

50 participants were recruited for the study, with 25 assigned to placebo and 25 to treatment group. Vildagliptin treatment resulted in a statistically significant reduction of HBA1c (p < 0.02) and hematocrit (p < 0.04), total cholesterol (p < 0.02), LDL cholesterol (p < 0.04), and total/HDL cholesterol ratio (P < 0.03) compared to the placebo group. Also, vildagliptin had a protective effect on DFU wound healing, evidenced by the odds ratio (OR) favoring the intervention of 11.2 (95% CI 1.1-113.5; p < 0.04) and the average treatment effect on the treated (ATET) for vildagliptin treatment group showed increased healing by 35% (95%CI; 10-60, p = 0.01) compared to placebo with the model adjusted for microvascular complications, smoking, amputation, dyslipidemia, peripheral vascular disease (PVD) and duration of diabetes.

CONCLUSIONS

Vildagliptin treatment was effective in healing DFU in addition to controlling the diabetes. Our findings support the use of DPP4is as a preferred option for treating ulcers in patients with diabetes. Further studies on a larger population are warranted to confirm our findings and understand how DPP4is could affect inflammation and DFU healing.

Mini-TrpRS is essential for IFNγ-induced monocyte-derived giant cell formation

Truncated tryptophanyl-tRNA synthetase (mini-TrpRS), like any other aminoacyl-tRNA synthetases, canonically functions as a protein synthesis enzyme. Here we provide evidence for an additional signaling role of mini-TrpRS in the formation of monocyte-derived multinuclear giant cells (MGCs). Interferon-gamma (IFNγ) readily induced monocyte aggregation leading to MGC formation with paralleled marked upregulation of mini-TrpRS. Small interfering (si)RNA, targeting mini-TrpRS in the presence of IFNγ prevented monocyte aggregation. Moreover, blockade of mini-TrpRS, either by siRNA, or the cognate amino acid and decoy substrate D-Tryptophan to prevent mini-TrpRS signaling, resulted in a marked reduction in expression of the purinergic receptor P2X 7 (P2RX7) in monocytes activated by IFNγ. Our findings identify mini-TrpRS as a critical signaling molecule in a mechanism by which IFNγ initiates monocyte-derived giant cell formation.

Role of inflammatory cytokines in genesis and treatment of atherosclerosis

Atherosclerosis demonstrates an increased rate of vascular smooth muscle cells (VSMC) plasticity characterized by switching from the differentiated contractile phenotype to a de-differentiated synthetic state. In healthy blood vessels, phenotypic switching represents a fundamental property of VSMC in maintaining vascular homeostasis. However, in atherosclerosis, it is an initial and necessary step in VSMC-derived foam cell formation. These foam cells play a decisive role in atherosclerosis progression since approximately half of all the foam cells are of VSMC origin. Our recent work showed that interferon-gamma (IFN-γ), a primary inflammatory cytokine in progressive atherosclerosis, mediates VSMC phenotype switching exclusively through upregulating mini-tryptophanyl-tRNA synthetase (mini-TrpRS). Here, we discuss the pro-atherosclerotic implication of this phenomenon that inevitably occurs in the context of a more complex regulation mediated by IFN-γ. An emerging therapeutic option for patients with progressive atherosclerosis is also discussed.