Toll-like receptor protein 4 monoclonal antibody inhibits mmLDL-induced endothelium-dependent vasodilation dysfunction of mouse mesenteric arteries

Regulation by Nrf2 of IL-1β-induced inflammatory and oxidative response in VSMC and its relationship with TLR4

Introduction: Vascular oxidative stress and inflammation play an important role in the pathogenesis of cardiovascular diseases (CVDs). The proinflammatory cytokine Interleukin-1β (IL-1β) participates in the vascular inflammatory and oxidative responses and influences vascular smooth muscle cells (VSMC) phenotype and function, as well as vascular remodelling in cardiovascular diseases. The Toll-like receptor 4 (TLR4) is also involved in the inflammatory response in cardiovascular diseases. A relationship between Interleukin-1β and Toll-like receptor 4 pathway has been described, although the exact mechanism of this interaction remains still unknown. Moreover, the oxidative stress sensitive transcription factor nuclear factor-erythroid 2-related factor 2 (Nrf2) promotes the transcription of several antioxidant and anti-inflammatory genes. Nuclear factor-erythroid 2-related factor 2 activators have shown to possess beneficial effects in cardiovascular diseases in which oxidative stress and inflammation are involved, such as hypertension and atherosclerosis; however, the molecular mechanisms are not fully understood. Here, we analysed the role of Toll-like receptor 4 in the oxidative and inflammatory effects of Interleukin-1β as well as whether nuclear factor-erythroid 2-related factor 2 activation contributes to vascular alterations by modulating these effects. Materials: For this purpose, vascular smooth muscle cells and mice aortic segments stimulated with Interleukin-1β were used. Results: Interleukin-1β induces MyD88 expression while the Toll-like receptor 4 inhibitor CLI-095 reduces the Interleukin-1β-elicited COX-2 protein expression, reactive oxygen species (ROS) production, vascular smooth muscle cells migration and endothelial dysfunction. Additionally, Interleukin-1β increases nuclear factor-erythroid 2-related factor 2 nuclear translocation and expression of its downstream proteins heme oxygenase-1, NAD(P)H:quinone oxidoreductase 1 and superoxide dismutase-2, by an oxidative stress-dependent mechanism; moreover, Interleukin-1β reduces the expression of the nuclear factor-erythroid 2-related factor 2 inhibitor Keap1. The nuclear factor-erythroid 2-related factor 2 activator tert-butylhydroquinone (tBHQ) reduces the effects of Interleukin-1β on the increased reactive oxygen species production and the expression of the proinflammatory markers (p-p38, p-JNK, p-c-Jun, COX-2), the increased cell proliferation and migration and prevents the Interleukin-1β-induced endothelial dysfunction in mice aortas. Additionally, tert-butylhydroquinone also reduces the increased MyD88 expression, NADPHoxidase activity and cell migration induced by lipopolysaccharide. Conclusions: In summary, this study reveals that Toll-like receptor 4 pathway contributes to the prooxidant and proinflammatory Interleukin-1β-induced effects. Moreover, activation of nuclear factor-erythroid 2-related factor 2 prevents the deleterious effects of Interleukin-1β, likely by reducing Toll-like receptor 4-dependent pathway. Although further research is needed, the results are promising as they suggest that nuclear factor-erythroid 2-related factor 2 activators might protect against the oxidative stress and inflammation characteristic of cardiovascular diseases.

Pro-inflammatory Mediators and Oxidative Stress: Therapeutic Markers for Recurrent Angina Pectoris after Coronary Artery Stenting in Elderly Patients

BACKGROUND

Pro-inflammatory mediators and oxidative stress are related to severity of angina pectoris in patients with coronary heart disease.

OBJECTIVE

We evaluated the effects of pro-inflammatory mediators and oxidative stress on recurrent angina pectoris after coronary artery stenting in elderly patients.

METHODS

We determined the expression levels of malondialdehyde (MDA), acrolein (ACR), tumour necrosis factor-α (TNF-α), toll-like receptor 4 (TLR4), superoxide dismutase 3 (SOD3), paraoxonase-1 (PON-1), stromal cell-derived factor-1α (SDF-1α) and endothelial progenitor cells (EPCs) in elderly patients with recurrent angina pectoris after coronary artery stenting.

RESULTS

Levels of MDA, ACR, TNF-α and TLR4 were significantly increased (p<0.001), and levels of SOD3, PON-1, SDF-1α and EPCs were significantly decreased (p<0.001) in the elderly patients with recurrent angina pectoris after coronary artery stenting. MDA, ACR, TNF-α and TLR4 as markers of oxidative stress and pro-inflammatory mediators may have suppressed SOD3, PON-1, SDF-1α and EPCs as markers of anti-oxidative stress/anti-inflammatory responses. Oxidative stress and pro-inflammatory mediators were important factors involved in recurrent angina pectoris of elderly patients after coronary artery stenting.

CONCLUSION

Oxidative stress and pro-inflammatory mediators could be considered as potential non-invasive prognostic, predictive and therapeutic biomarkers for stable recurrent angina and recurrent unstable angina in the elderly patients after coronary artery stenting.

Modulation of the Innate Immune Response by Targeting Toll-like Receptors: A Perspective on Their Agonists and Antagonists

Toll-like receptors (TLRs) are a class of proteins that recognize pathogen-associated molecular patterns (PAMPs) and damaged-associated molecular patterns (DAMPs), and they are involved in the regulation of innate immune system. These transmembrane receptors, localized at the cellular or endosomal membrane, trigger inflammatory processes through either myeloid differentiation primary response 88 (MyD88) or TIR-domain-containing adapter-inducing interferon-β (TRIF) signaling pathways. In the last decades, extensive research has been performed on TLR modulators and their therapeutic implication under several pathological conditions, spanning from infections to cancer, from metabolic disorders to neurodegeneration and autoimmune diseases. This Perspective will highlight the recent discoveries in this field, emphasizing the role of TLRs in different diseases and the therapeutic effect of their natural and synthetic modulators, and it will discuss insights for the future exploitation of TLR modulators in human health.