Proinflammatory Events Research Articles

Okanin alleviates symptoms of nociceptive-like responses in diabetic peripheral neuropathy in type 1 diabetic Wistar rats by regulating the AGEs/NF-κB/Nrf-2 pathway

Elevated reactive species and AGEs contribute to deregulation of transcription factors e.g., NF-κB and Nrf2 in diabetic peripheral neuropathy (DPN). Okanin, a bioactive chalcone, is active against redox imbalance, immune response, and pro-inflammatory events. The current investigation assessed effects of okanin in streptozotocin-induced DPN in rats. Wistar rats were divided into 6 groups (n = 6): Control, DPN, Okanin 2.5, Okanin 5, Okanin 10, and Gpn (Gabapentin). After 6 weeks of streptozotocin (55 mg/kg) injection, okanin (2.5, 5, 10 mg/kg), and gabapentin (50 mg/kg), were administered for 4 weeks. The streptozotocin-induced reduction in body weight, and increased feed/water intake, insulin, glucose, and HbA1c levels were mitigated by okanin or gabapentin. In DPN rats, Okanin or gabapentin ameliorated insulin resistance and β-cell function, inflammatory indices, and oxidative stress in the sciatic nerve of rodents thereby culminating in a decrease in hyperalgesia and allodynia. Okanin and streptozotocin-treated rats had significantly declined levels of AGEs, the receptor for AGEs, and NF-κB, and an upsurge in Nrf2 expression. In streptozotocin-induced DPN model, okanin ameliorates nociceptive-like responses by regulating the AGEs/NF-κB/Nrf2 pathway, suggesting that okanin has therapeutic value against DPN which needs further studies involving human subjects.

Multifaceted approach to successful management of pediatric acute liver failure: High-volume plasma exchange as a pivotal intervention

Abstract: Pediatric acute liver failure (pALF) poses a formidable clinical challenge characterized by rapid hepatocyte necrosis and pro-inflammatory events. The urgency of pALF necessitates advanced therapeutic modalities, prompting the exploration of high-volume plasma exchange (HVPE) as a sophisticated intervention. This case report delves into the intricate management of a 16-year-old female with hyperacute liver failure secondary to hepatitis A, highlighting the critical need for nuanced and multidisciplinary approaches. The case unfolds through a detailed description of symptoms, clinical decision-making, and the therapeutic journey. The management includes a calculated deferral of liver transplantation in favor of HVPE, with a focus on the rationale for choosing HVPE over continuous renal replacement therapy. Technical aspects of the procedure, such as blood volume calculations and procedural details, are meticulously outlined. Laboratory investigations track the patient’s progress, showcasing the profound impact of HVPE on clinical and laboratory recovery. The patient’s response to HVPE is evident in the comprehensive clinical and laboratory recovery observed after the intervention. The resolution of encephalopathy, successful extubation, and eventual discharge highlight the positive outcomes achieved through the judicious application of HVPE. However, the procedure is not without challenges, as the emergence of hypertension during the second and third cycles and a lone episode of seizure require swift and careful management. The management of pALF demands a sophisticated and multidimensional approach, especially when liver transplantation is not immediately feasible. This case report underscores the nuanced decision-making involved in selecting extracorporeal therapies, with a focus on the successful application of HVPE. HVPE, as recommended by the American Society for Apheresis, emerges as a promising intervention in the context of pALF, offering a viable option when liver transplantation is deferred due to advanced encephalopathy. The favorable outcomes and considerations of cost-effectiveness and procedural simplicity further accentuate the potential of HVPE as a cornerstone in the critical care of pediatric patients with acute liver failure.

In vitro evidence of antioxidant and anti-inflammatory effects of a new nutraceutical formulation explains benefits in a clinical setting of COPD patients.

Background and Aim: Increased oxidative stress within the airways is associated to epithelial damage and amplification of inflammatory responses that in turn contribute to Chronic Obstructive Pulmonary Disease (COPD) progression. This study was aimed to identify whether a new formulation of N-acetylcisteine (NAC), carnitine, curcumin and B2 vitamin could counteract oxidative stress and downstream pro-inflammatory events promoted by cigarette smoke extract (CSE) exposure in primary bronchial epithelial cells (PBEC), both submerged/undifferentiated (S-PBEC) and cultured at the air-liquid interface (ALI-PBEC). Methods: PBEC were exposed to CSE with/without the new formulation or NAC alone and ROS production, IL-8 and IL-6 gene expression and protein release were evaluated. Results: CSE increased ROS, IL-8 and IL-6 gene expression and protein release and the new formulation counteracted these effects. NAC alone was not effective on IL-8 and IL-6 release. The effects of a similar nutraceutical formulation were evaluated in COPD patients treated for six months. The results showed that the treatment reduced the concentration of IL-8 in nasal wash and improved quality of life. Conclusion: The tested formulation, exerting antioxidant and anti-inflammatory effects, can preserve airway epithelial homeostasis and improve clinical symptoms in COPD.

Differential signalling requirements for RIPK1-dependent pyroptosis in neutrophils and macrophages

TLR4 and TNFR1 signalling promotes potent proinflammatory signal transduction events, thus, are often hijacked by pathogenic microorganisms. We recently reported that myeloid cells retaliate Yersinia blockade of TAK1/IKK signalling by triggering RIPK1-dependent caspase-8 activation that promotes downstream GSDMD and GSDME-mediated pyroptosis in macrophages and neutrophils respectively. However, the upstream signalling events for RIPK1 activation in these cells are not well defined. Here, we demonstrate that unlike in macrophages, RIPK1-driven pyroptosis and cytokine priming in neutrophils are driven through TNFR1 signalling, while TLR4-TRIF signalling is dispensable. Furthermore, we demonstrate that activation of RIPK1-dependent pyroptosis in neutrophils during Yersinia infection requires IFN-γ priming, which serves to induce surface TNFR1 expression and amplify soluble TNF secretion. In contrast, macrophages utilise both TNFR1 and TLR4-TRIF signalling to trigger cell death, but only require TRIF but not autocrine TNFR1 for cytokine production. Together, these data highlight the emerging theme of cell type-specific regulation in cell death and immune signalling in myeloid cells.

The G Protein Estrogen Receptor (GPER) is involved in the resistance to the CDK4/6 inhibitor palbociclib in breast cancer

BackgroundThe cyclin D1-cyclin dependent kinases (CDK)4/6 inhibitor palbociclib in combination with endocrine therapy shows remarkable efficacy in the management of estrogen receptor (ER)-positive and HER2-negative advanced breast cancer (BC). Nevertheless, resistance to palbociclib frequently arises, highlighting the need to identify new targets toward more comprehensive therapeutic strategies in BC patients.MethodsBC cell lines resistant to palbociclib were generated and used as a model system. Gene silencing techniques and overexpression experiments, real-time PCR, immunoblotting and chromatin immunoprecipitation studies as well as cell viability, colony and 3D spheroid formation assays served to evaluate the involvement of the G protein-coupled estrogen receptor (GPER) in the resistance to palbociclib in BC cells. Molecular docking simulations were also performed to investigate the potential interaction of palbociclib with GPER. Furthermore, BC cells co-cultured with cancer-associated fibroblasts (CAFs) isolated from mammary carcinoma, were used to investigate whether GPER signaling may contribute to functional cell interactions within the tumor microenvironment toward palbociclib resistance. Finally, by bioinformatics analyses and k-means clustering on clinical and expression data of large cohorts of BC patients, the clinical significance of novel mediators of palbociclib resistance was explored.ResultsDissecting the molecular events that characterize ER-positive BC cells resistant to palbociclib, the down-regulation of ERα along with the up-regulation of GPER were found. To evaluate the molecular events involved in the up-regulation of GPER, we determined that the epidermal growth factor receptor (EGFR) interacts with the promoter region of GPER and stimulates its expression toward BC cells resistance to palbociclib treatment. Adding further cues to these data, we ascertained that palbociclib does induce pro-inflammatory transcriptional events via GPER signaling in CAFs. Of note, by performing co-culture assays we demonstrated that GPER contributes to the reduced sensitivity to palbociclib also facilitating the functional interaction between BC cells and main components of the tumor microenvironment named CAFs.ConclusionsOverall, our results provide novel insights on the molecular events through which GPER may contribute to palbociclib resistance in BC cells. Additional investigations are warranted in order to assess whether targeting the GPER-mediated interactions between BC cells and CAFs may be useful in more comprehensive therapeutic approaches of BC resistant to palbociclib.

Rac1 promotes the lipopolysaccharide-induced inflammatory response and contraction-associated proteins (CAPs) expression in mouse uterine smooth muscle cells

Activation of the maternal immune system leads to a downstream cascade of proinflammatory events that culminate in the activation of spontaneous uterine contractions, which is associated with preterm birth. Ras-related C3 botulinum toxin substrate 1 (Rac1) is a crucial protein related to cell contraction and inflammation. The main purpose of this study was to explore the role and function of Rac1′s regulation of inflammation through in- vivo and in-vitro experiments. Rac1 inhibitor was used in animal model of preterm birth and cells isolated from the uterine tissues of pregnant mice on gestational day 16 were transfected with adenovirus to knockdown or overexpress Rac1 and treated with the Calcium–calmodulin-dependent protein kinase II (CaMKII) inhibitor KN93. The expression of Rac1, uterine contraction-associated proteins (CAPs) (COX-2 and Connexin43), and inflammatory cytokines, were assessed by Western blotting and RTPCR.LPS upregulated Rac1, COX-2 and Connexin43 expression in uterine smooth muscle cells (USMCs). The expression of inflammatory cytokines, COX-2, and Connexin43 was significantly decreased in shRac1-transfected cells compared with cells stimulated with LPS only. Rac1 overexpression led to an increase in the expression of inflammatory cytokines, COX-2, and Connexin43. Furthermore, after Rac1 overexpression, KN93 reduced the expression of uterine contraction-associated proteins and inflammatory cytokines. It is thought that the effect of Rac1 on inflammatory cytokine and contraction-associated protein expression in USMCs is mediated by CaMKII. Rac1 can modulate the expression of contraction-associated proteins and inflammatory cytokines through the CaMKII pathway. Rac1 could be an effective therapeutic target for improving the outcome of preterm birth.

Quantitative analysis of heme and hemoglobin for the detection of intravascular hemolysis

BackgroundIntravascular hemolysis is associated with massive release of hemoglobin and consequently labile heme into the blood, resulting in prothrombotic and proinflammatory events in patients. Though heme is well-known to participate in these adverse effects, it is not monitored. Instead, haptoglobin and hemoglobin serve as clinical biomarkers. The quantification of labile heme together with hemoglobin, however, should be considered in clinical diagnosis as well, to obtain a complete picture of the hemolytic state in patients. So far, quantification techniques for labile heme were not yet systematically analyzed and compared for their clinical application potential, especially in the presence of hemoglobin. ResultsTwo commercial assays (Heme Assay Kit®, Hemin Assay Kit®) and five common approaches (pyridine hemochromogen assay, apo-horseradish peroxidase-based assay, UV/Vis spectroscopy, HPLC, mass spectrometry) were analyzed concerning their linearity, accuracy, and precision, as well as their ability to distinguish between hemoglobin-bound heme and labile heme. Further, techniques for the quantification of hemoglobin (Harboe method, SLS method, Hemastix®) were included to study their selectivity for hemoglobin and potential interference by the presence of labile heme. Both, indirect and direct approaches were suitable for the determination of a wide concentration of heme (∼0.02–45 μM) and hemoglobin (∼0.002–17 μM). A clear distinction between hemoglobin-bound heme and labile heme with one method was not possible. Thus, a novel combined approach is presented and applied to human and porcine plasma samples for the determination of hemoglobin and labile heme. SignificanceOur results demonstrate the need to develop improved techniques to differentiate labile and protein-bound heme for early detection of intravascular hemolysis. Here, we present a novel strategy by combining two spectroscopic methods, which is most reliable as an easy-to-use tool for the determination of hemoglobin and heme levels in plasma samples for the diagnosis of intravascular hemolysis and in basic biomedical research.

Stage-dependent immunity orchestrates AQP4 antibody-guided NMOSD pathology: a role for netting neutrophils with resident memory T cells in situ.

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease of the CNS characterized by the production of disease-specific autoantibodies against aquaporin-4 (AQP4) water channels. Animal model studies suggest that anti-AQP4 antibodies cause a loss of AQP4-expressing astrocytes, primarily via complement-dependent cytotoxicity. Nonetheless, several aspects of the disease remain unclear, including: how anti-AQP4 antibodies cross the blood-brain barrier from the periphery to the CNS; how NMOSD expands into longitudinally extensive transverse myelitis or optic neuritis; how multiphasic courses occur; and how to prevent attacks without depleting circulating anti-AQP4 antibodies, especially when employing B-cell-depleting therapies. To address these knowledge gaps, we conducted a comprehensive 'stage-dependent' investigation of immune cell elements in situ in human NMOSD lesions, based on neuropathological techniques for autopsied/biopsied CNS materials. The present study provided three major findings. First, activated or netting neutrophils and melanoma cell adhesion molecule-positive (MCAM+) helper T (TH) 17/cytotoxic T (TC) 17 cells are prominent, and the numbers of these correlate with the size of NMOSD lesions in the initial or early-active stages. Second, forkhead box P3-positive (FOXP3+) regulatory T (Treg) cells are recruited to NMOSD lesions during the initial, early-active or late-active stages, suggesting rapid suppression of proinflammatory autoimmune events in the active stages of NMOSD. Third, compartmentalized resident memory immune cells, including CD103+ tissue-resident memory T (TRM) cells with long-lasting inflammatory potential, are detected under "standby" conditions in all stages. Furthermore, CD103+ TRM cells express high levels of granzyme B/perforin-1 in the initial or early-active stages of NMOSD in situ. We infer that stage-dependent compartmentalized immune traits orchestrate the pathology of anti-AQP4 antibody-guided NMOSD in situ. Our work further suggests that targeting activated/netting neutrophils, MCAM+ TH17/TC17 cells, and CD103+ TRM cells, as well as promoting the expansion of FOXP3+ Treg cells, may be effective in treating and preventing relapses of NMOSD.

The Standardized Extract of Centella asiatica and Its Fractions Exert Antioxidative and Anti-Neuroinflammatory Effects on Microglial Cells and Regulate the Nrf2/HO-1 Signaling Pathway.

Neuroinflammation and oxidative stress can aggravate the progression of Alzheimer's disease (AD). Centella asiatica has been traditionally consumed for memory and cognition. The triterpenes (asiaticoside, madecassoside, asiatic acid, madecassic acid) have been standardized in the ethanolic extract of Centella asiatica (SECA). The bioactivity of the triterpenes in different solvent polarities of SECA is still unknown. In this study, the antioxidative and anti-neuroinflammatory effects of SECA and its fractions were explored on lipopolysaccharides (LPS)-induced microglial cells. HPLC measured the four triterpenes in SECA and its fractions. SECA and its fractions were tested for cytotoxicity on microglial cells using MTT assay. NO, pro-inflammatory cytokines (TNF-α, IL-6, IL-1β), ROS, and MDA (lipid peroxidation) produced by LPS-induced microglial cells were measured by colorimetric assays and ELISA. Nrf2 and HO-1 protein expressions were measured using western blotting. The SECA and its fractions were non-toxic to BV2 microglial cells at tested concentrations. The levels of NO, TNF-α, IL-6, ROS, and lipid peroxidation in LPS-induced BV2 microglial cells were significantly reduced (p < 0.001) by SECA and its fractions. SECA and some of its fractions can activate the Nrf2/HO-1 signaling pathway by significantly enhancing (p < 0.05) the Nrf2 and HO-1 protein expressions. This study suggests that the inhibitory activity of SECA and its fractions on pro-inflammatory and oxidative stress events may be the result of the activation of antioxidant defense systems. The potential of SECA and its fractions in reducing neuroinflammation and oxidative stress can be further studied as a potential therapeutic strategy for AD.

Small Molecules for the Treatment of Long-COVID-Related Vascular Damage and Abnormal Blood Clotting: A Patent-Based Appraisal.

People affected by COVID-19 are exposed to, among others, abnormal clotting and endothelial dysfunction, which may result in deep vein thrombosis, cerebrovascular disorders, and ischemic and non-ischemic heart diseases, to mention a few. Treatments for COVID-19 include antiplatelet (e.g., aspirin, clopidogrel) and anticoagulant agents, but their impact on morbidity and mortality has not been proven. In addition, due to viremia-associated interconnected prothrombotic and proinflammatory events, anti-inflammatory drugs have also been investigated for their ability to mitigate against immune dysregulation due to the cytokine storm. By retrieving patent literature published in the last two years, small molecules patented for long-COVID-related blood clotting and hematological complications are herein examined, along with supporting evidence from preclinical and clinical studies. An overview of the main features and therapeutic potentials of small molecules is provided for the thromboxane receptor antagonist ramatroban, the pan-caspase inhibitor emricasan, and the sodium-hydrogen antiporter 1 (NHE-1) inhibitor rimeporide, as well as natural polyphenolic compounds.

Pathogenesis-Guided Rational Engineering of Nanotherapies for the Targeted Treatment of Abdominal Aortic Aneurysm by Inhibiting Neutrophilic Inflammation.

Abdominal aortic aneurysm (AAA) remains a fatal disease in the elderly. Currently, no drugs can be clinically used for AAA therapy. Considering the pivotal role of neutrophils in the pathogenesis of AAA, herein we propose the targeted therapy of AAA by site-specifically regulating neutrophilic inflammation. Based on a luminol-conjugated α-cyclodextrin material (LaCD), intrinsically anti-inflammatory nanoparticles (NPs) were engineered by simple nanoprecipitation, which were examined as a nanotherapy (defined as LaCD NP). After efficient accumulation in the aneurysmal aorta and localization in pathologically relevant inflammatory cells in rats with CaCl2-induced AAA, LaCD NP significantly alleviated AAA progression, as implicated by the decreased aortic expansion, suppressed elastin degradation, inhibited calcification, and improved structural integrity of the abdominal aorta. By functionalizing LaCD NP with alendronate, a calcification-targeting moiety, the in vivo aneurysmal targeting capability of LaCD NP was considerably enhanced, thereby affording significantly potentiated therapeutic outcomes in AAA rats. Mechanistically, LaCD NP can effectively inhibit neutrophil-mediated inflammatory responses in the aneurysmal aorta. Particularly, LaCD NP potently attenuated the formation of neutrophil extracellular traps (NETs), thereby suppressing NETs-mediated pro-inflammatory events and NETosis-associated negative effects responsible for AAA progression. Consequently, we demonstrated the effectiveness and underlying mechanisms of anti-NETosis nanotherapies for the targeted treatment of AAA. Our findings provide promising insights into discovering precision therapies for AAA and other inflammatory vascular diseases.

Adipose Tissue Macrophages.

In obesity, adipose tissue macrophages (ATMs) are abundant immune cells in the adipose tissue and are known as inducers of metabolic inflammation that may lead to insulin resistance and immune disorders associated with obesity. However, much less is known about the ontogeny and physiological functions of ATMs in lean adipose tissue. ATMs are present at birth and actively participate in the synthesis of mediators that induce lipolysis, mitobiogenesis, and thermogenesis in adipocytes. Later in life ATMs limit the thermogenic competence of the adipocytes and favor lipid storage. ATMs respond to lipid overload of adipocytes in obesity with a sequence of pro-inflammatory events, including inflammasome activation and pyroptosis, as well as stimulation of nuclear factor kappa B and interferon regulatory factors that evoke an uncontrolled inflammation. ATMs are life-long constituents of the adipose tissue and hence signals that control ATM development and ATM-adipocyte interactions determine adipose tissue health.

Proinflammatory state promotes red blood cell alloimmunization in pediatric patients with sickle cell disease.

We examined risk factors for RBC alloimmunization in pediatric patients with sickle cell disease (SCD), focusing on recipients' inflammatory state at the time of transfusion and anti-inflammatory role of hydroxyurea (HU). Among 471 participants, 55 (11.70%) participants were alloimmunized and formed 59 alloantibodies and 17 autoantibodies with an alloimmunization rate of 0.36 alloantibodies per 100 units. Analysis of 27 participants who formed alloantibodies with specificities showed 23.8% (30/126) of units transfused during a proinflammatory event resulted in alloantibody formation compared to 2.8% (27/952) of units transfused at steady state. Therefore, transfusion during proinflammatory events increased the risk for alloimmunization (odds ratio [OR]: 4.22; 95% confidence interval [CI]: 1.64-10.85; p = 0.003). Further analysis of all the 471 participants showed alloimmunization of episodically transfused patients who received transfusion mostly during proinflammatory events was not reduced by HU therapy (OR: 6.52; 95% CI: 0.85-49.77; p = 0.071), HU therapy duration (OR: 1.13; 95% CI: 0.997-1.28; p = 0.056) or HU dose (OR: 1.06; 95% CI: 0.96-1.16; p = 0.242). The analysis also identified high transfusion burden (OR: 1.02; 95% CI: 1.003-1.04; p = 0.020) and HbSS and HbSβ0-thalassemia genotypes (OR: 11.22, 95% CI: 1.51-83.38, p = 0.018) as additional risk factors for alloimmunization. In conclusion, the inflammatory state of transfusion recipients affects the risk of RBC alloimmunization, which is not modified by HU therapy. Judicious use of transfusion during proinflammatory events is critical for preventing alloimmunization.

Cisplatin triggers oxidative stress, apoptosis and pro-inflammatory responses by inhibiting the SIRT1-mediated Nrf2 pathway in chondrocytes.

Although the height of the proliferating layer that was suppressed in the growth plate has been recognized as an adverse effect of cisplatin in pediatric cancer survivors, the detailed pathological mechanism has not been elucidated. Sirtuin-1 (SIRT1) has been reported as an essential modulator of cartilage homeostasis, but its role in cisplatin-induced damage of chondrocytes remains unclear. In this study, we examined how cisplatin affected the expression of SIRT1 and cell viability. Next, we showed downregulation of SIRT1 after cisplatin treatment resulted in suppression of Peroxisome proliferator-activated receptor-gamma coactivator (PGC-1α), leading to inhibition of Nrf2 nuclear translocation and subsequently decreased Heme oxygenase-1(HO-1) and NAD(P)H Quinone Dehydrogenase 1(NQO-1) expression. Blockage of the SIRT1/ PGC-1α axis not only increased oxidative stress with lower antioxidant SOD and GSH, but also contributed to mitochondrial dysfunction evidenced by the collapse of membrane potential and repression of mitochondrial DNA copy number and ATP. We also found that Cisplatin up-regulated the p38 phosphorylation, pro-inflammatory events and matrix metalloproteinases (MMPs) in chondrocytes through the SIRT1-modulated antioxidant manner. Collectively, our findings suggest that preservation of SIRT1 in chondrocytes may be a potential target to ameliorate growth plate dysfunction for cisplatin-receiving pediatric cancer survivors.

The Molecular Mechanisms of Neuroinflammation in Alzheimer's Disease, the Consequence of Neural Cell Death.

Alzheimer's disease (AD) is accompanied by neural cell loss and memory deficit. Neural cell death, occurring via apoptosis and autophagy, is widely observed in the AD brain in addition to neuroinflammation mediated by necroptosis and the NLRP3 inflammasome. Neurotoxicity induced by amyloid-beta (Aβ) and tau aggregates leads to excessive neural cell death and neuroinflammation in the AD brain. During AD progression, uncontrolled neural cell death results in the dysregulation of cellular activity and synaptic function. Apoptosis mediated by pro-apoptotic caspases, autophagy regulated by autophagy-related proteins, and necroptosis controlled by the RIPK/MLKL axis are representative of neural cell death occurred during AD. Necroptosis causes the release of cellular components, contributing to the pro-inflammatory environment in the AD brain. Inordinately high levels of neural cell death and pro-inflammatory events lead to the production of pro-inflammatory cytokines and feed-forward hyper neuroinflammation. Thus, neural cell death and neuroinflammation cause synaptic dysfunction and memory deficits in the AD brain. In this review, we briefly introduce the mechanisms of neural cell death and neuroinflammation observed in the AD brain. Combined with a typical strategy for targeting Aβ and tau, regulation of neural cell death and neuroinflammation may be effective for the amelioration of AD pathologies.

Complement Activation-Independent Attenuation of SARS-CoV-2 Infection by C1q and C4b-Binding Protein.

The complement system is a key component of the innate immune response to viruses and proinflammatory events. Exaggerated complement activation has been attributed to the induction of a cytokine storm in severe SARS-CoV-2 infection. However, there is also an argument for the protective role of complement proteins, given their local synthesis or activation at the site of viral infection. This study investigated the complement activation-independent role of C1q and C4b-binding protein (C4BP) against SARS-CoV-2 infection. The interactions of C1q, its recombinant globular heads, and C4BP with the SARS-CoV-2 spike and receptor binding domain (RBD) were examined using direct ELISA. In addition, RT-qPCR was used to evaluate the modulatory effect of these complement proteins on the SARS-CoV-2-mediated immune response. Cell binding and luciferase-based viral entry assays were utilised to assess the effects of C1q, its recombinant globular heads, and C4BP on SARS-CoV-2 cell entry. C1q and C4BP bound directly to SARS-CoV-2 pseudotype particles via the RBD domain of the spike protein. C1q via its globular heads and C4BP were found to reduce binding as well as viral transduction of SARS-CoV-2 spike protein expressing lentiviral pseudotypes into transfected A549 cells expressing human ACE2 and TMPRSS2. Furthermore, the treatment of the SARS-CoV-2 spike, envelope, nucleoprotein, and membrane protein expressing alphaviral pseudotypes with C1q, its recombinant globular heads, or C4BP triggered a reduction in mRNA levels of proinflammatory cytokines and chemokines such as IL-1β, IL-8, IL-6, TNF-α, IFN-α, and RANTES (as well as NF-κB) in A549 cells expressing human ACE2 and TMPRSS2. In addition, C1q and C4BP treatment also reduced SARS-CoV-2 pseudotype infection-mediated NF-κB activation in A549 cells expressing human ACE2 and TMPRSS2. C1q and C4BP are synthesised primarily by hepatocytes; however, they are also produced by macrophages, and alveolar type II cells, respectively, locally at the pulmonary site. These findings support the notion that the locally produced C1q and C4BP can be protective against SARS-CoV-2 infection in a complement activation-independent manner, offering immune resistance by inhibiting virus binding to target host cells and attenuating the infection-associated inflammatory response.

Exogenous IL-10 posttreatment along with TLR4 and TNFR1 blockade improves tissue antioxidant status by modulating sepsis-induced macrophage polarization.

Multi-organ dysfunction is one of the major reasons behind the high mortality of sepsis throughout the world. With the pathophysiology of sepsis remaining largely unknown, the uncontrolled reactive oxygen species (ROS) production along with the decreased antioxidants contributes to the progression toward septic shock. Being the effector cells of the innate immunity system, macrophages secrete both pro-inflammatory and anti-inflammatory mediators during inflammation. Lipopolysaccharide (LPS) binding to toll-like receptor 4 (TLR4) releases TNF-α, which initiates pro-inflammatory events through tumor necrosis factor receptor 1 (TNFR1) signaling. However, it is counteracted by the anti-inflammatory interleukin 10 (IL-10) causing decreased oxidative stress. Our study thus aimed to assess the effects of exogenous IL-10 treatment post-neutralization of TLR4 and TNFR1 (by anti-TLR4 antibody and anti-TNFR1 antibody, respectively) in an in vivo murine model of LPS-sepsis. We have also examined the tissue-specific antioxidant status in the spleen, liver, and lungs along with the serum cytokine levels in adult male Swiss albino mice to determine the functional association with the disease. The results showed that administration of recombinant IL-10 post-neutralization of the receptors was beneficial in shifting the macrophage polarization to the anti-inflammatory M2 phenotype. IL-10 treatment significantly downregulated the free radicals production resulting in diminished lipid peroxidase (LPO) levels. The increased antioxidant activities of superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GRX ) conferred protection against LPS-induced sepsis. Western blot data further confirmed diminished expressions of TLR4 and TNFR1 along with suppressed stress-activated protein kinases/Jun amino-terminal kinases (SAPK/JNK) and increased SOD and CAT expressions, which altogether indicated that neutralization of TLR4 and TNFR1 along with IL-10 posttreatment might be a potential therapeutic measure for the treatment of sepsis.

Early life stress in mice leads to impaired colonic corticosterone production and prolonged inflammation following induction of colitis

Early life stress (ELS) is an environmental trigger linked to increased risk of inflammatory bowel disease (IBD). Our goal was to identify mechanisms whereby ELS in mice affects susceptibility to, and/or severity of, intestinal inflammation. We hypothesized that ELS alters the delicate balance of typical homeostatic mediators in the intestinal microenvironment, predisposing ELS-exposed individuals to IBD onset or worsened disease upon a pro-inflammatory triggering event within the gut. We utilized 2 published animal models of ELS. In the first model, newborn mice were separated from the dam daily for 4-8 hours beginning on postnatal day 2, then weaned early on postnatal day 17. Normally reared (NR) control mice were left undisturbed with the dams until standard weaning on postnatal day 21. In the second model, dams were fed the synthetic glucocorticoid – dexamethasone, or vehicle ad libitum in drinking water (3 μg/mL) on post-partum days 1-14. Colitis was induced in 4-week-old mice via intraperitoneal injection of IL-10 receptor blocking antibody (100 μg) every 5 days for 15 days. Five or 15 days later, histological colitis scores and colonic transcripts for Tnf, glucocorticoid receptors, and steroidogenic enzymes were measured. ELS-exposed mice displayed altered mucosa-associated immune cell balances, with an initial deficit in anti-inflammatory IL-10-producing CD4 T cells at 4-wks of age (n≥11, p&lt;0.05), followed by an increase in IFNγ-producing CD4 T cells at 8-wks of age (n≥7, p&lt;0.05). ELS-exposed mice also displayed reduced levels of the glucocorticoid, corticosterone in the plasma (n≥10, p&lt;0.01) as well as locally within the colon (n≥7, p&lt;0.05). Upon colitis induction, NR control animals showed improvements in indices of inflammation following cessation of IL-10 receptor blockade, whereas ELS-exposed animals maintained high levels of intestinal Tnf (n≥7, p&lt;0.01) and histological signs of colitis (n≥7, p&lt;0.05). In colitic animals, prior exposure to ELS was associated with significantly lower expression of genes associated with corticosterone synthesis ( Cyp11a1; n≥5, p&lt;0.05) and responsiveness ( Nr3c1, Nr5a2; n≥5, p&lt;0.01). Finally, ex-vivo TNF stimulation of colonic crypt cells from ELS mice led to increased inhibition of corticosterone synthesis, relative to NR control mice (n≥4, p&lt;0.05). Our study identifies impaired local colonic glucocorticoid production and responsiveness as a potential mechanism whereby ELS predisposes to chronic colitis in susceptible hosts. Crohn's and Colitis Foundation Research Initiatives Award This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Natural Antimicrobials Promote the Anti-Oxidative Inhibition of COX-2 Mediated Inflammatory Response in Primary Oral Cells Infected with Staphylococcus aureus, Streptococcus pyogenes and Enterococcus faecalis.

Staphylococcus aureus, Streptococcus pyogenes and Enterococcus faecalis can colonize the tooth root canals, adhere to dentin walls, and frequently cause periodontitis in dogs. Bacterial periodontal diseases are common in domesticated pets, causing severe oral cavity inflammation and a strong immune response. This study investigates the antioxidant effect of a natural antimicrobial mixture (Auraguard-Ag) on the ability of S. aureus, S. pyogenes and E. faecalis to infect primary canine oral epithelial cells as well as its impact on their virulence factors. Our data show that a concentration of 0.25% Ag is sufficient to inhibit the growth of all three pathogens, whereas a concentration of 0.5% will become bactericidal. The sub-inhibitory concentration of 0.125% Ag reveals that the antimicrobial mixture can significantly reduce biofilm formation and exopolysaccharide production. The impact on these virulence factors was further translated into a significantly reduced ability to infect primary canine oral epithelial cells and restore epithelial tight junctions, with no impact on the epithelial cell viability. The post-infection inflammatory cytokines (IL-1β and IL-8) and the COX-2 mediator were also reduced both in mRNA and protein expression levels. The oxidative burst, detected upon infection, was also decreased in the presence of Ag, as our results show a significant decrease in H2O2 released by the infected cells. We show that inhibition of either NADPH or ERK activity will result in a downregulation of COX-2 expression and lower levels of H2O2 in infected cells. Conclusively, our study shows that natural antimicrobials reduce pro-inflammatory events, post infection, through an antioxidative mechanism that involves the downregulation of the COX-2 mediator via the inactivation of ERK in the absence of H2O2. As a result, they significantly reduce the risk of secondary bacterial infections and host oxidative stress caused by Staphylococcus aureus, Streptococcus pyogenes and Enterococcus faecalis accumulation in biofilms in an in vitro canine oral infection model.

Role of Defensins in Tumor Biology.

Defensins have long been considered as merely antimicrobial peptides. Throughout the years, more immune-related functions have been discovered for both the α-defensin and β-defensin subfamily. This review provides insights into the role of defensins in tumor immunity. Since defensins are present and differentially expressed in certain cancer types, researchers started to unravel their role in the tumor microenvironment. The human neutrophil peptides have been demonstrated to be directly oncolytic by permealizing the cell membrane. Further, defensins can inflict DNA damage and induce apoptosis of tumor cells. In the tumor microenvironment, defensins can act as chemoattractants for subsets of immune cells, such as T cells, immature dendritic cells, monocytes and mast cells. Additionally, by activating the targeted leukocytes, defensins generate pro-inflammatory signals. Moreover, immuno-adjuvant effects have been reported in a variety of models. Therefore, the action of defensins reaches beyond their direct antimicrobial effect, i.e., the lysis of microbes invading the mucosal surfaces. By causing an increase in pro-inflammatory signaling events, cell lysis (generating antigens) and attraction and activation of antigen presenting cells, defensins could have a relevant role in activating the adaptive immune system and generating anti-tumor immunity, and could thus contribute to the success of immune therapy.