Orexins in apoptosis: a dual regulatory role

The orexins, also referred to as hypocretins, are neuropeptides that originate from the lateral hypothalamus (LH) region of the brain. They are composed of two small peptides, orexin-A, and orexin-B, which are broadly distributed throughout the central and peripheral nervous systems. Orexins are recognized to regulate diverse functions, involving energy homeostasis, the sleep-wake cycle, stress responses, and reward-seeking behaviors. Additionally, it is suggested that orexin-A deficiency is linked to sleepiness and narcolepsy. The orexins bind to their respective receptors, the orexin receptor type 1 (OX1R) and type 2 (OX2R), and activate different signaling pathways, which results in the mediation of various physiological functions. Orexin receptors are widely expressed in different parts of the body, including the skin, muscles, lungs, and bone marrow. The expression levels of orexins and their receptors play a crucial role in apoptosis, which makes them a potential target for clinical treatment of various disorders. This article delves into the significance of orexins and orexin receptors in the process of apoptosis, highlighting their expression levels and their potential contributions to different diseases. The article offers an overview of the existing understanding of the orexin/receptor system and how it influences the regulation of apoptosis.

The role of matrix metalloproteinase-2 and miR-196a2 in bronchial asthma pathogenesis and diagnosis

Background

Bronchial asthma is a persistent inflammatory respiratory condition that restricts the passage of air and causes hyperresponsiveness. Chronic asthma can be classified into three categories: mild, moderate, and severe. Remodeling took place as the extracellular matrix accumulated in the walls of the airways. Inflammation occurs as a result of the damage caused by matrix metalloproteinase-2 (MMP-2) to basement membrane type IV collagen. The severity of asthma may be associated with miR-196a2. The objective of our study was to investigate the underlying mechanisms and clinical relevance of miR-196a2 and MMP-2 serum levels in relation to the severity of asthma.

Methods

This study recruited 85 controls and 95 asthmatics classified as mild, moderate, or severe. Expression of miR-196a2 was measured by quantitative reverse transcriptase PCR. Using the enzyme-linked immunosorbent assay (ELISA), MMP-2, IL-6, and total immunoglobulin E (IgE) levels in the serum of asthmatics of various grades were compared to a control group. MMP-2's diagnostic and prognostic potential was determined using ROC curve analysis. This study also measured blood Eosinophils and PFTs. We examined MMP-2's connections with IgE, blood Eosinophils, and PFTs.

Results

The current investigation found that miR-196a2 expression was significantly higher in the control group than in asthmatic patients as a whole. The study found that severe asthmatics had higher MMP-2, IL-6, and IgE serum levels than healthy controls. We identified the MMP-2 serum concentration cutoff with great sensitivity and specificity. Significant relationships between MMP-2 serum level and miR-196a2 expression in the patient group with severe asthmatics were found. The MMP-2, IL-6, and IgE serum levels were considerably higher in mild, moderate, and severe asthmatics than controls. The miR-196a2 expression and MMP-2 serum concentration correlated positively with IgE and blood eosinophils % and negatively with all lung function tests in the asthmatic patient group.Conclusion: the study revealed that the elevated miR-196a2 expression and serum concentration of MMP-2, IL-6, and IgE associated with elevated blood eosinophils % is associated with pathophysiology and degree of asthma severity. The miR-196a2 expression and MMP-2 serum concentration have a promising diagnostic and prognostic ability in bronchial asthma.

Corrigendum: Unveiling the therapeutic potential of exogenous β-hydroxybutyrate for chronic colitis in rats: novel insights on autophagy, apoptosis, and pyroptosis

[This corrects the article DOI: 10.3389/fphar.2023.1239025.].

Linagliptin, a DPP-4 inhibitor, activates AMPK/FOXO3a and suppresses NFκB to mitigate the debilitating effects of diethylnitrosamine exposure in rat liver: Novel mechanistic insights

Accumulating evidence suggests that dysregulation of FOXO3a plays a significant role in the progression of various malignancies, including hepatocellular carcinoma (HCC). FOXO3a inactivation, driven by oncogenic stimuli, can lead to abnormal cell growth, suppression of apoptosis, and resistance to anticancer drugs. Therefore, FOXO3a emerges as a potential molecular target for the development of innovative treatments in the era of oncology. Linagliptin (LNGTN), a DPP-4 inhibitor known for its safe profile, has exhibited noteworthy anti-inflammatory and anti-oxidative properties in previous in vivo studies. Several potential molecular mechanisms have been proposed to explain these effects. However, the capacity of LNGTN to activate FOXO3a through AMPK activation has not been investigated. In our investigation, we examined the potential repurposing of LNGTN as a hepatoprotective agent against diethylnitrosamine (DENA) intoxication. Additionally, we assessed LNGTN's impact on apoptosis and autophagy. Following a 10-week administration of DENA, the liver underwent damage marked by inflammation and early neoplastic alterations. Our study presents the first experimental evidence demonstrating that LNGTN can reinstate the aberrantly regulated FOXO3a activity by elevating the nuclear fraction of FOXO3a in comparison to the cytosolic fraction, subsequent to AMPK activation. Moreover, noteworthy inactivation of NFκB induced by LNGTN was observed. These effects culminated in the initiation of apoptosis, the activation of autophagy, and the manifestation of anti-inflammatory, antiproliferative, and antiangiogenic outcomes. These effects were concomitant with improved liver function and microstructure. In conclusion, our findings open new avenues for the development of novel therapeutic strategies targeting the AMPK/FOXO3a signaling pathway in the management of chronic liver damage.

Itraconazole halts hepatocellular carcinoma progression by modulating sonic hedgehog signaling in rats: A novel therapeutic approach

Liver cancer stands as the fourth leading global cause of death, and its prognosis remains grim due to the limited effectiveness of current medical interventions. Among the various pathways implicated in the development of hepatocellular carcinoma (HCC), the hedgehog signaling pathway has emerged as a crucial player. Itraconazole, a relatively safe and cost-effective antifungal medication, has gained attention for its potential as an anticancer agent. Its primary mode of action involves inhibiting the hedgehog pathway, yet its impact on HCC has not been elucidated. The main objective of this study was to investigate the effect of itraconazole on diethylnitrosamine-induced early-stage HCC in rats. Our findings revealed that itraconazole exhibited a multifaceted arsenal against HCC by downregulating the expression of key components of the hedgehog pathway, shh, smoothened (SMO), and GLI family zinc finger 1 (GLI1), and GLI2. Additionally, itraconazole extended survival and improved liver tissue structure, attributed mainly to its inhibitory effects on hedgehog signaling. Besides, itraconazole demonstrated a regulatory effect on Notch1, and Wnt/β-catenin signaling molecules. Consequently, itraconazole displayed diverse anticancer properties, including anti-inflammatory, antiangiogenic, antiproliferative, and apoptotic effects, as well as the potential to induce autophagy. Moreover, itraconazole exhibited a promise to impede the transformation of epithelial cells into a more mesenchymal-like phenotype. Overall, this study emphasizes the significance of targeting the hedgehog pathway with itraconazole as a promising avenue for further exploration in clinical studies related to HCC treatment.

Unveiling the therapeutic potential of exogenous β-hydroxybutyrate for chronic colitis in rats: novel insights on autophagy, apoptosis, and pyroptosis

Ulcerative colitis (UC) is a chronic relapsing inflammatory disease of the colorectal area that demonstrates a dramatically increasing incidence worldwide. This study provides novel insights into the capacity of the exogenous β-hydroxybutyrate and ketogenic diet (KD) consumption to alleviate dextran sodium sulfate (DSS)-induced UC in rats. Remarkably, both interventions attenuated disease activity and colon weight-to-length ratio, and improved macro and microstructures of the damaged colon. Importantly, both β-hydroxybutyrate and KD curbed the DSS-induced aberrant NLRP3 inflammasome activation as observed in mRNA and protein expression analysis. Additionally, inhibition of the NLRP3/NGSDMD-mediated pyroptosis was detected in response to both regimens. In parallel, these modalities attenuated caspase-1 and its associated consequences of IL-1β and IL-18 overproduction. They also mitigated apoptosis as indicated by the inactivation of caspase-3. The anti-inflammatory effects of BHB and KD were confirmed by the reported decline in the levels of inflammatory markers including MPO, NFκB, IL-6, and TNF-α. Moreover, these interventions exhibited antioxidative properties by reducing ROS production and improving antioxidative enzymes. Their effectiveness in mitigating UC was also evident in the renovation of normal intestinal epithelial barrier function, as shown by correcting the discrepancies in the levels of tight junction proteins ZO-1, OCLN, and CLDN5. Furthermore, their effects on the intestinal microbiota homeostasis were investigated. In terms of autophagy, exogenous β-hydroxybutyrate upregulated BECN-1 and downregulated p62, which may account for its superiority over KD in attenuating colonic damage. In conclusion, this study provides experimental evidence supporting the potential therapeutic use of β-hydroxybutyrate or β-hydroxybutyrate-boosting regimens in UC.

Alvespimycin Exhibits Potential Anti-TGF-β Signaling in the Setting of a Proteasome Activator in Rats with Bleomycin-Induced Pulmonary Fibrosis: A Promising Novel Approach

Idiopathic pulmonary fibrosis (IPF) is an irreversible and life-threatening lung disease of unknown etiology presenting only a few treatment options. TGF-β signaling orchestrates a cascade of events driving pulmonary fibrosis (PF). Notably, recent research has affirmed the augmentation of TGF-β receptor (TβR) signaling via HSP90 activation. HSP90, a molecular chaperone, adeptly stabilizes and folds TβRs, thus intricately regulating TGF-β1 signaling. Our investigation illuminated the impact of alvespimycin, an HSP90 inhibitor, on TGF-β-mediated transcriptional responses by inducing destabilization of TβRs. This outcome stems from the explicit interaction of TβR subtypes I and II with HSP90, where they are clients of this cellular chaperone. It is worth noting that regulation of proteasome-dependent degradation of TβRs is a critical standpoint in the termination of TGF-β signal transduction. Oleuropein, the principal bioactive compound found in Olea europaea, is acknowledged for its role as a proteasome activator. In this study, our aim was to explore the efficacy of a combined therapy involving oleuropein and alvespimycin for the treatment of PF. We employed a PF rat model that was induced by intratracheal bleomycin infusion. The application of this dual therapy yielded a noteworthy impediment to the undesired activation of TGF-β/mothers against decapentaplegic homologs 2 and 3 (SMAD2/3) signaling. Consequently, this novel combination showcased improvements in both lung tissue structure and function while also effectively restraining key fibrosis markers such as PDGF-BB, TIMP-1, ACTA2, col1a1, and hydroxyproline. On a mechanistic level, our findings unveiled that the antifibrotic impact of this combination therapy likely stemmed from the enhanced degradation of both TβRI and TβRII. In conclusion, the utilization of proteasomal activators in conjunction with HSP90 inhibitors ushers in a promising frontier for the management of PF.

Evaluation of the anti-inflammatory and analgesic effects of Cu(II) and Zn(II) complexes derived from 2-(naphthalen-1-yloxy)-N'-(1-(pyridin-2-1)ethylidene) acetohydrazide

New Cu(II) and Zn(II) complexes of 2-(naphthalen-1-yloxy)-N'-(1-(pyridin-2-yl)ethylidene) acetohydrazide (HA2PNA) have been prepared and characterized by elemental analyses, spectral (IR, UV-visible, ESR and 1H NMR) as well as magnetic and thermal measurements. According to the data, the complexes assigned the formulae: [Cu(A2PNA)2]H2O and [Zn(A2PNA)(OAc)(H2O)], respectively. IR data revealed that the ligand acts as before ONN and after morever ONN mononegative tridentate via deprotonated carbonyl oxygen (CO) and both (CN)imine and (CN)pyridine nitrogen atoms. The bond lengths, bond angles, HOMO, LUMO, dipole moment and charges on the atoms have been calculated by using density functional theory (DFT) at B3LYP level with 6-31G and 6-31G(d,p) basis sets to confirm the geometry of the ligand and the investigated complexes. Also, the kinetic parameters were determined for each thermal degradation stage of the complexes using Coats-Redfern and Horowitz-Metzger methods. Moreover, the complexes have been tested for anti-inflammatory and analgesic activity in rat model of collagen adjuvant arthritis and compared with piroxicam. All the compounds showed a significant anti-inflammatory and analgesic effect versus piroxicam.