Diminazene aceturate attenuates hepatic ischemia/reperfusion injury in mice

Diminazene aceturate attenuates systemic inflammation via microbiota gut-5-HT brain-spleen sympathetic axis in male mice

The sympathetic arm of the inflammatory reflex is the efferent pathway through which the central nervous system (CNS) can control peripheral immune responses. Diminazene aceturate (DIZE) is an antiparasitic drug that has been reported to exert protective effects on various experimental models of inflammation. However, the pathways by which DIZE promotes a protective immunomodulatory effects still need to be well established, and no studies demonstrate the capacity of DIZE to modulate a neural reflex to control inflammation. C57BL/6 male mice received intraperitoneal administration of DIZE (2 mg/Kg) followed by lipopolysaccharide (LPS, 5 mg/Kg, i.p.). Endotoxemic animals showed hyperresponsiveness to inflammatory signals, while those treated with DIZE promoted the activation of the inflammatory reflex to attenuate the inflammatory response during endotoxemia. The unilateral cervical vagotomy did not affect the anti-inflammatory effect of DIZE in the spleen and serum. At the same time, splenic denervation attenuated tumor necrosis factor (TNF) synthesis in the spleen and serum. Using broad-spectrum antibiotics for two weeks showed that LPS modulated the microbiota to induce a pro-inflammatory profile in the intestine and reduced the serum concentration of tryptophan and serotonin (5-HT), while DIZE restored serum tryptophan and increased the hypothalamic 5-HT levels. Furthermore, the treatment with 4-Chloro-DL-phenylalanine (pcpa, an inhibitor of 5-HT synthesis) abolished the anti-inflammatory effects of the DIZE in the spleen. Our results indicate that DIZE promotes microbiota modulation to increase central 5-HT levels and activates the efferent sympathetic arm of the inflammatory reflex to control splenic TNF production in endotoxemic mice.

TXNIP knockdown ameliorates hepatic ischemia/reperfusion injury by inhibiting apoptosis and improving mitochondrial dysfunction via HIF-1α

This study aims to investigate whether thioredoxin-interacting protein (TXNIP) regulates cell viability, cell apoptosis and mitochondrial damage in OGD/R-induced hepatocytes and to explore its underlying mechanism. AML12 cells were cultured under oxygen-glucose deprivation/reperfusion (OGD/R) conditions. TXNIP mRNA was detected using qRT-PCR, and the TXNIP protein was analyzed using western blotting. TXNIP-targeted short hairpin RNA (sh-TXNIP) lentivirus was used to infect the AML12 cells. CCK8 and TUNEL assays were applied to detect cell viability and apoptosis, respectively. DCFH-DA probe was used to determine reactive oxygen species (ROS) release level, and JC-1 probe was used to evaluate mitochondrial membrane potential (MMP). The localization of TXNIP and HIF-1α was observed using immunofluorescence. Our results showed that TXNIP markedly increased in AML12 cells treated with OGD/R. TXNIP knockdown increased cell viability and reduced cell apoptosis under OGD/R treatment. Moreover, MMP significantly increased and ROS release decreased in cells after TXNIP knockdown under OGD/R treatment. Additionally, TXNIP knockdown markedly increased the expression of HIF-1α. HIF-1α exhibited nuclear translocation following OGD/R induction, and TXNIP knockdown further promoted it. Compared with the OGD/R + sh-TXNIP group, HIF-1α agonist ML228 inhibited cell apoptosis and ROS release, and increased MMP. However, HIF-1α inhibitor PX478 had the opposite effect. In summary, TXNIP deletion ameliorated AML12 cell injury caused by OGD/R via promoting HIF-1α expression and nuclear translocation, manifested by inhibiting cell apoptosis and alleviating mitochondrial dysfunction.

Loureirin B improves H/R-induced hepatic ischemia-reperfusion injury by downregulating ALOX5 to regulate mitochondrial homeostasis

This study was conceived to explore the role and the mechanism of Loureirin B (LB) in hepatic IRI. The viability of LB-treated AML-12 cells was assessed using CCK-8 assay and inflammatory cytokines were detected using ELISA. The activities of ROS and oxidative stress markers MDA, SOD, and GSH-Px were detected using DCFH-DA and corresponding assay kits. The cell apoptosis and caspase3 activity were estimated with flow cytometry and caspase3 assay kits. The expressions of arachidonate 5-lipoxygenase (ALOX5) and apoptosis- and mitochondrial dynamics-related proteins were detected using western blot. The interaction between LB and ALOX5 was analyzed with molecular docking. The transfection efficacy of oe-ALOX5 was examined with RT-qPCR and western blot. Mitochondrial membrane potential was detected with JC-1 staining and immunofluorescence (IF) assay was employed to estimate mitochondrial fusion and fission. The present work found that LB revived the viability, inhibited inflammatory response, suppressed oxidative stress, repressed the apoptosis, and maintained mitochondrial homeostasis in H/R-induced AML-12 cells, which were all reversed by ALOX5 overexpression. Collectively, LB regulated mitochondrial homeostasis by downregulating ALOX5, thereby improving hepatic IRI.

Targeting PI3K/p-Akt/eNOS, Nrf2/HO-1, and NF-κB/p53 signaling pathways by angiotensin 1-7 protects against liver injury induced by ischemia-reperfusion in rats

The liver is an important organ, and hepatic ischemia-reperfusion (IR) injury is a frequent pathophysiological process that can cause significant morbidity and mortality. Thus, our study aimed to investigate the effect of targeting PI3K/p-Akt/eNOS (phosphoinositide 3-kinase/phospho-protein kinase B/endothelial nitric oxide synthase), Nrf2/HO-1 (nuclear factor-erythroid 2-related factor-2/heme oxygenase-1), and NF-κB/p53 (nuclear factor-κB/tumor protein 53) signaling pathways by using angiotensin (1-7) [ang-(1-7)] against hepatic injury induced by IR. Thirty-two male rats were included in sham group, ang-(1-7)-treated group, hepatic IR group, and hepatic IR group treated with ang-(1-7). The levels of hepatic ang-(1-7), angiotensin II (Ang II), angiotensin-converting enzyme 2 (ACE2), HO-1, malondialdehyde (MDA), PI3K, and p-Akt were assessed. The expressions of eNOS and B-cell leukemia/lymphoma-2 (BCL-2) in the liver were determined. Histological assessment and immunohistochemical expression of NF-κB, p53, and Nrf2 were carried out. The levels of reduced glutathione (GSH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in serum were estimated. Results showed that administration of ang-(1-7) to hepatic IR rats led to significant amelioration of hepatic damage through a histological evaluation that was associated with significant upregulation of the expressions of PI3K/p-Akt/eNOS and Nrf2/HO-1 with downregulation of NF-κB/p53 signaling pathways. In conclusion, PI3K/p-Akt/eNOS and Nrf2/HO-1 signaling pathways are involved in the protective effects of ang-(1-7) against hepatic damage induced by IR. Therefore, ang-(1-7) can be used to prevent hepatic IR, which occurs in certain conditions such as liver transplantation, hemorrhagic shock, and severe infection.

Nephroprotective effects of diminazene on doxorubicin-induced acute kidney injury in rats

This study aimed to investigate the potential protective effects of diminazene, an activator of angiotensin II converting enzyme (ACE2), on kidney function and structure in rats with acute kidney injury (AKI) induced by the anticancer drug doxorubicin (DOX). The impact of diminazene was compared to that of two other drugs: the ACE inhibitor lisinopril and the angiotensin II type 1 (AT1) receptor blocker valsartan. Rats were subjected to a single intraperitoneal injection of DOX (13.5 mg/kg) on the 5th day, either alone or in combination with diminazene (15 mg/kg/day), lisinopril (10 mg/kg/day), or valsartan (30 mg/kg/day) for 8 consecutive days. Various markers related to kidney function, oxidative stress, and inflammation were measured in plasma and urine. Additionally, kidney tissues were assessed histopathologically. DOX-induced nephrotoxicity was confirmed by elevated levels of plasma urea, creatinine, and neutrophil gelatinase-associated lipocalin (NGAL). DOX also led to increased urinary N-acetyl-β-D-glucosaminidase (NAG) activity and decreased creatinine clearance, albumin levels, and osmolality. Moreover, DOX caused a reduction in renal oxidative stress markers, including superoxide dismutase (SOD), glutathione reductase (GR), and catalase activities, while increasing malondialdehyde (MDA) levels. It also raised plasma inflammatory markers, tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β). Concurrently administering diminazene significantly mitigated these DOX-induced changes, including histopathological alterations like renal tubule necrosis, tubular casts, shrunken glomeruli, and increased renal fibrosis. Similar protective effects were observed with lisinopril and valsartan. These protective effects, at least in part, appear to result from the anti-inflammatory and antioxidant properties of these drugs. In summary, this study suggests that the administration of diminazene, lisinopril, or valsartan had comparable effects in ameliorating the biochemical and histopathological aspects of DOX-induced acute kidney injury in rats.

Diminazene aceturate or losartan ameliorates the functional, radiological and histopathological alterations in knee osteoarthritis rodent model: repurposing of the ACE2/Ang1-7/MasR cascade

PURPOSE

Current therapies for osteoarthritis (OA) are limited to analgesics and anti-inflammatory drugs. Considering the importance of oxidative stress and inflammatory mediators in OA etiology, we tested the hypothesis that targeting the renin-angiotensin-aldosterone system (RAAS) can improve OA anomalies. Diminazene (DIZE), an activator of angiotensin-converting enzyme 2 and the angiotensin 2 type-1 receptor blocker losartan (LOS) were used for this purpose.

METHODS

OA was induced by a single intra-articular injection of monosodium iodoacetate. The effects of exposure to DIZE or LOS for 21 days on OA anomalies in rats' knees were investigated. Evaluation of motor function, nociception, and inflammatory response was done using rotarod, knee bend and knee swelling tests. Markers of knee joint inflammation, and cellular oxidation in addition to the RAAS biomarkers, were assessed in knee tissues, along with radiological and histopathological investigations.

RESULTS

Elevations in inflammatory and oxidative markers in knee tissues of OA rats were mostly improved by the two therapeutic drugs. Such effect was also reflected in the rotarod, knee bend and knee swelling tests. Treatment with DIZE has shown a more prominent effect than LOS in controlling OA-associated inflammation and cellular oxidation. Markers of RAAS have also shown better responsiveness to DIZE over LOS.

CONCLUSIONS

DIZE has shown a prominent increase in the angiotensin 1-7 amount, highlighting the involvement of the signaling pathway in the immunomodulatory effect. The radiological and histopathology examination came to confirm the outcome of biochemical markers, nominating diminazene aceturate as a possible therapeutic option for OA.

The ACE2 activator diminazene aceturate ameliorates colitis by repairing the gut-vascular barrier in mice

Alleviating vascular barrier injury improves colitis. Angiotensin converting enzyme 2/angiotensin 1-7/Mas receptor (ACE2/Ang1-7/MasR) axis-related drugs have various biological properties, such as inhibition of inflammation and fibrosis, but their role in improving the gut-vascular barrier (GVB) has rarely been reported. This study aims to investigate the effects of diminazene aceturate (DIZE), an ACE2 activator, on vascular barrier damage in colitis. Mice were randomly divided into three groups: control, dextran sulfate sodium salt (DSS), and DIZE+DSS. Mice in the DSS group drank DSS for 8 days starting on day 4. Mice in the DIZE+DSS group were pregavaged with DIZE for 3 days and then drank DSS for 8 days while continuing to be gavaged with DIZE for 4 days. Mice were euthanized and samples were collected on the last day. Injury to colonic structure and colonic microvasculature was assessed by visual observation and appropriate staining. DSS-induced colonic and microvascular pathological damage in mice was substantially reversed by DIZE treatment. Molecular pathways were investigated by Western blot, quantitative real-time polymerase chain reaction (qRT-PCR), and enzyme linked immunosorbent assay (ELISA). DSS treatment upregulated angiotensin converting enzyme (ACE), angiotensin type 1 receptor (AT1R) protein, pro-inflammatory cytokines and inhibited tight junction-related protein expression. DIZE treatment activated ACE2/MasR protein expression and reversed epithelial barrier damage and inflammatory infiltration during DSS injury. In addition, DIZE treatment inhibited vascular endothelial growth factor A/vascular endothelial growth factor receptor 2/proto-oncogene tyrosine-protein kinase Src (VEGFA/VEGFR2/Src) pathway activation and restored vascular adhesion-linker protein vascular endothelial cadherin (VE-cadherin) expression during DSS injury. In conclusion, DIZE treatment ameliorated colitis, which was associated with balancing the two axes of the renin-angiotensin system (RAS) and repairing the GVB injury.