Regulation of the Expression of Inducible Nitric Oxide Synthase

High throughput screening identifies auranofin and pentamidine as potent compounds that lower IFN-γ-induced Nitric Oxide and inflammatory responses in mice: DSS-induced colitis and Salmonella Typhimurium-induced sepsis

Interferon-gamma (IFN-γ) is a type II interferon produced primarily by T cells and natural killer cells. IFN-γ induces the expression of inducible nitric oxide synthase (NOS2) to catalyze Nitric Oxide (NO) production in various immune and non-immune cells. Excessive IFN-γ-activated NO production is implicated in several inflammatory diseases, including peritonitis and inflammatory bowel diseases. In this study, we screened the LOPAC®1280 library in vitro on the H6 mouse hepatoma cell line to identify novel non-steroidal small molecule inhibitors of IFN-γ-induced NO production. Compounds with the highest inhibitory activity were validated, which led to identifying the lead compounds: pentamidine, azithromycin, rolipram, and auranofin. Auranofin was the most potent compound determined based on IC50 and goodness of fit analyses. Mechanistic investigations revealed that majority of the lead compounds suppress the IFN-γ-induced transcription of Nos2 without negatively affecting NO-independent processes, such as the IFN-γ-induced transcription of Irf1, Socs1 and MHC class 1 surface expression. However, all four compounds lower IFN-γ-induced reactive oxygen species amounts. In addition, auranofin significantly reduced IFN-γ-mediated NO and IL6 production in resident as well as thioglycolate-elicited peritoneal macrophages (PMs). Finally, in vivo testing of the lead compounds in the pre-clinical DSS-induced ulcerative colitis mice model revealed pentamidine and auranofin to be the most potent and protective lead compounds. Also, pentamidine and auranofin greatly increase the survival of mice in another inflammatory model: Salmonella Typhimurium-induced sepsis. Overall, this study identifies novel anti-inflammatory compounds targeting IFN-γ-induced NO-dependent processes to alleviate two distinct inflammatory models of disease.

Uro-protective role of chrysin against cyclophosphamide-induced hemorrhagic cystitis in rats involving the turning-off NF-κB/P38-MAPK, NO/PARP-1 and STAT-3 signaling cascades

BACKGROUND

Chemotherapeutic agents are used to treat a wide range of cancer types, but they cause serious side effects which must be managed after treatment. Cyclophosphamide (CYP) is one of chemotherapeutic drugs that causes hemorrhagic cystitis (HC) induced by acrolein.

OBJECTIVE

The current investigation intended to uncover the role of chrysin (CHR) in CYP-induced HC in rats and explore the signaling pathway beyond this effect.

ANALYSIS

process: A single dose of CYP (200 mg/kg/IP) was injected, meanwhile CHR (25, 50 and 100 mg/kg, P.O) was administered respectively for 7 days prior to CYP administration and resume for 7 days afterwards. Urinary bladder tissue was then isolated from all rats to assess oxidative stress and inflammatory biomarkers. Moreover, histopathological examinations were performed.

RESULTS

Treatment with CHR showed a marked alleviation in oxidative stress biomarkers induced by CYP. Furthermore, CHR treatment presented a dose-dependent boost in the anti-inflammatory; IL-10 levels and a drop in the pro-inflammatory biomarkers; IL-1β, IL-6, and TNF-α. Additionally, stabilization of the PARP-1 protein expression was also detected thus preventing DNA damage. Similarly, CHR restored the urinary bladder cGMP levels. Notably, CHR treatment was accompanied with inhibition in NF-κB/p38-MAPK, NO/PARP-1 and STAT-3 signaling pathways inflammatory cascades. All these findings conformed with the histopathological examinations as well as iNOS immunostaining in the urinary bladder tissue.

CONCLUSION

Co-administration of CHR and CYP attained uro-protective therapeutic potential to guard against HC as well as spot the tangled mechanism of CHR in attenuating the HC induced by CYP.

Histone Methylation and Oxidative Stress in Cardiovascular Diseases

Oxidative stress occurs when ROS overproduction overwhelms the elimination ability of antioxidants. Accumulated studies have found that oxidative stress is regulated by histone methylation and plays a critical role in the development and progression of cardiovascular diseases. Targeting the underlying molecular mechanism to alter the interplay of oxidative stress and histone methylation may enable creative and effective therapeutic strategies to be developed against a variety of cardiovascular disorders. Recently, some drugs targeting epigenetic modifiers have been used to treat specific types of cancers. However, the comprehensive signaling pathways bridging oxidative stress and histone methylation need to be deeply explored in the contexts of cardiovascular physiology and pathology before clinical therapies be developed. In the present review, we summarize and update information on the interplay between histone methylation and oxidative stress during the development of cardiovascular diseases such as atherosclerosis, coronary artery disease, pulmonary hypertension, and diabetic macro- and microvascular pathologies.

Vitamin D Levels Correlate with Metabolic Syndrome Criteria in Algerian Patients: The Ex-vivo Immunomodulatory Effect of α, 25 Dihydroxyvitamin D3

BACKGROUND

Metabolic syndrome (MetS) is a combination of metabolic disorders with increased risks for several diseases, such as cardiovascular diseases and diabetes. It is associated with the presence of various inflammatory molecules. Vitamin D plays an important role in the regulation of metabolism homeostasis.

OBJECTIVE

The main goal of this work is to investigate vitamin D levels among Algerian MetS patients and its possible outcomes on key molecules of the immune response, as well, the immunomodulatory effects of its active metabolite.

METHODS

We evaluated vitamin D status by the electrochemiluminescence method, Nitric Oxide (NO) levels by the Griess method and Matrix Metalloproteinases (MMPs) activities such as MMP-2 and MMP-9 by zymography in plasma of patients and healthy controls (HC). The immunomodulatory effects of the active metabolite of vitamin D (α-25 (OH)2D3) on the production of NO, IL-6, IL-10, TGF- β and s-CTLA-4 were assessed by Griess method and ELISA, in peripheral blood mononuclear cells (PBMCs) of Algerian MetS patients and HC. MMPs activities were also determined ex-vivo, while iNOS expression was assessed by immunofluorescence staining.

RESULTS

Severe vitamin D deficiency was registered in Algerian MetS patients. The deficiency was found to be associated with an elevated in vivo NO production and high MMPs activity. Interestingly, α-25 (OH)2D3 declined the NO/iNOS system and IL-6 production, as well as MMPs activities. However, the ex-vivo production of IL-10, TGF-β increased in response to the treatment. We observed in the same way, the implication of s-CTLA-4 in MetS, which was markedly up-regulated with α-25 (OH)2D3.

CONCLUSION

Our report indicated the relationship between MetS factors and Vitamin D deficiency. The ex-vivo findings emphasize its impact on maintaining regulated immune balance.

Anti-Inflammatory Effects of Formononetin 7-O-phosphate, a Novel Biorenovation Product, on LPS-Stimulated RAW 264.7 Macrophage Cells

Biorenovation is a microbial enzyme-catalyzed structural modification of organic compounds with the potential benefits of reduced toxicity and improved biological properties relative to their precursor compounds. In this study, we synthesized a novel compound verified as formononetin 7-O-phosphate (FMP) from formononetin (FM) using microbial biotransformation. We further compared the anti-inflammatory properties of FMP to FM in lipopolysaccharide (LPS)-treated RAW264.7 macrophage cells. We observed that cell viabilities and inhibitory effects on LPS-induced nitric oxide (NO) production were greater in FMP-treated RAW 264.7 cells than in their FM-treated counterparts. In addition, FMP treatment suppressed the production of proinflammatory cytokines such as prostaglandin-E₂ (PGE₂), interleukin-6 (IL-6), and interleukin-1β (IL-1β) in a dose-dependent manner and concomitantly decreased the mRNA expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2). We also found that FMP exerted its anti-inflammatory effects through the downregulation of the extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and nuclear factor kappa B (NF-κB) signaling pathways. In conclusion, we generated a novel anti-inflammatory compound using biorenovation and demonstrated its efficacy in cell-based in vitro assays.

Effect of Telmisartan in the Oxidative Stress Components Induced by Ischemia Reperfusion in Rats

The therapeutic effects of telmisartan, an angiotensin II receptor antagonist and a peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist, have been demonstrated in several disorders. It has antioxidant and immune response modulator properties and has shown promising results in the treatment of an ischemia/reperfusion (I/R) lesion. In this study, a skeletal muscle (right gastrocnemius muscle) I/R lesion was induced in rats and different reperfusion times (1 h, 24 h, 72 h, 7-day, and 14-day subgroups) were assessed. Furthermore, levels of oxidative markers such as enzymatic scavengers (catalase (CAT) and superoxide dismutase (SOD)) and metabolites (nitrates and 8-oxo-deoxyguanosine) were determined. The degree of tissue injury (total lesioned fibers and inflammatory cell count) was also evaluated. We observed an increase in CAT and SOD expression levels under telmisartan treatment, with a decrease in injury and oxidative biomarker levels in the 72 h, 7-day, and 14-day subgroups. Telmisartan reduced oxidative stress and decreased the damage of the I/R lesion.

[Posttraumatic dystrophy. Diagnosis and therapy after distal radius fractures and hand injuries]

BACKGROUND

Posttraumatic dystrophy manifests as signs and symptoms of endothelial dysfunction in the microcirculation with pronounced involvement of arteriovenous (AV) anastomosis.

PATIENTS AND METHODS

Blood gas analysis was performed in 28 patients with persistent painful swelling 6-14 weeks after distal radius fracture or hand injury. The patients showed higher levels of venous oxygenation on the affected side in comparison to the contralateral arm. Furthermore, an increased perfusion and an AV shunt situation were proven by radionuclide angiography. These findings correlate with insufficient oxygen utilization by the tissue (dystrophy = capillary malperfusion). Pathophysiologically, complex processes must be assumed which require a multimodal therapy and treatment focuses on open AV shunts.

RESULTS

The disastrous consequences of hand dystrophy (loss of function due to fibrosis) could be prevented in all patients. Statistical analyses between affected and normal hands showed significant differences.

CONCLUSION

Posttraumatic dystrophy needs early detection for successful therapy and should not be identified under the umbrella term "complex regional pain syndrome" (CRPS).