Antimicrobial protein REG3A and signaling networks are predictive of stroke outcomes

Abstract

Regenerating Family Member 3 Alpha (REG3A) is a multifunctional protein with antimicrobial activity, and primarily secreted by the intestine and pancreas. Studies have shown an increased expression of REG3A in systemic inflammatory responses to acute injury and infection, but studies investigating REG3A during the pathogenesis of ischemic stroke are limited. The aims of this study were to examine the associations between arterial expression of REG3A and other arterial inflammatory proteins implicated in stroke pathogenesis, as well as associations between REG3A and markers of poor outcome for ischemic stroke. The University of Kentucky Blood and Clot Thrombectomy Registry and Collaboration (BACTRAC) protocol (clinicaltrials.gov NCT03153683) utilizes thrombectomy to isolate intracranial arterial blood (i.e. distal to thrombus) and systemic arterial blood (i.e. carotid). Samples were analyzed by Olink Proteomics for N = 42 subjects. Statistical analyses of plasma proteins included 2‐sample t‐tests, spearman and biserial correlations, and robust regression models to elucidate network signaling and association to clinical outcomes. Results indicated that levels of systemic REG3A were positively correlated with inflammatory proteins interleukin IL6 (R = 0.344, p = 0.030) and IL17C (R = 0.468, p = 0.002). 2‐sided t‐ tests examining differences of systemic REG3A within quartiles of NIHSS admission score depicted significant differences between quartiles. Those with NIHSS scores corresponding to moderate and moderate‐severe neurofunctional deficits had significantly higher levels of systemic REG3A compared to those with NIHSS scores corresponding to mild and mild‐moderate neurofunctional deficits (p = 0.016). STRING analyses of proteins in each robust regression model demonstrated substantial networking between REG3A and other systemic proteins highly relevant to ischemic stroke. The present study provides novel data on systemic REG3A in the context of ischemic stroke. These results demonstrate the influential role of REG3A regarding surrogate functional and radiographic outcomes of stroke severity. Additionally, they provide novel insight into the role of REG3A and related proteins during the complex neuroinflammatory process of ischemic stroke. These data provide a foundation for future studies to investigate REG3A and related networking proteins as potential biomarkers with prognostic potential, as well as potential therapeutic targets.

Gastrointestinal Dysfunction in Stroke

“…191,194,195 In a study of 40 ischemic stroke patients, Reg3 was positively correlated with IL-6/17C and a higher NIHSS score, suggesting it is upregulated in response to ischemic stroke. 191 Another gut hormone, trefoil factor-3 (TFF-3), is secreted from goblet cells and supports mucosal integrity and healing postinjury. 192 In an animal model of stroke, TFF-3-deficient mice exhibited significantly higher levels of cell death and cerebral infarcts; intravenous administration of recombinant TFF-3 reversed cerebral injury and improved motor function.…”

“…186 The GI tract contains the largest endocrine "organ" in the body, the enteric endocrine cells, which can release biologically active "gut-derived" hormones (e.g., cholecystokinin, chromogranin, gastrin, glucagon-like peptide-1, norepinephrine, secretin, serotonin, and somatostatin) with complex immune and/or protective actions that may play a role in ischemic stroke. 130,[186][187][188][189][190][191][192] An imbalance of gut hormones can perpetuate GI dysbiosis; for example, a higher concentration of norepinephrine can lead to opportunistic pathogen proliferation, 193 which has been demonstrated in an experimental stroke model. 145 Further, gut-derived hormones likely play a role in responding to the proinflammatory response poststroke.…”

Daphnetin attenuates intestinal inflammation, oxidative stress, and apoptosis in ulcerative colitis via inhibiting REG3A‐dependent JAK2/STAT3 signaling pathway

“…20,21 REG3A is a multifunctional protein with antimicrobial activity, and primarily secreted by the intestine and pancreas. 22 Studies have shown an increased expression of REG3A in systemic inflammatory responses to acute injury and infection. 23,24 More importantly, enteric delivery of REG3A was revealed to alter the intestinal microbiota and controls inflammation in UC model mice.…”

“…REG proteins are associated with the pathogenesis in the gastrointestinal (GI) tract 20,21 . REG3A is a multifunctional protein with antimicrobial activity, and primarily secreted by the intestine and pancreas 22 . Studies have shown an increased expression of REG3A in systemic inflammatory responses to acute injury and infection 23,24 .…”

Short Chain Fatty Acids Taken at Time of Thrombectomy in Acute Ischemic Stroke Patients Are Independent of Stroke Severity But Associated With Inflammatory Markers and Worse Symptoms at Discharge

“…Previously published studies that used this protocol have provided novel data relating proteomic characteristics with clinical outcomes. These studies have shown that there are significantly lower intracranial expressions of proteins involved in th2 and neutrophil proliferation [i.e., C-C motif chemokine 19 (CCL19), 20 (CCL20), and 23 (CCL23)] during stroke (30) and that the expression of various cytokines, chemokines, and inflammatory proteins taken at the time of thrombectomy may predict stroke severity (30)(31)(32)(33). More so, alterations in peri-infarct blood gases and electrolytes were found to exist during stroke, and some of these are sex-specific (34,35).…”