Protective Effect Of SP600125 Research Articles

Protective effects of SP600125 on mice infected with H1N1 influenza A virus.

Influenza A virus (IAV) can cause high morbidity and mortality globally every year. Myriad host kinases and their related signaling pathways are involved in IAV infection, and the important role of the c-Jun N-terminal kinase signaling pathway during infection has been demonstrated. SP600125, an inhibitor of c-Jun N-terminal kinase, was found in our previous study to suppress IAV replication in vitro. In this study, we established a mouse model of H1N1 IAV infection and treated the mice with SP600125 to study its protective effect. The results showed that SP600125 treatment reduced the pulmonary inflammatory response, lung injury, and pulmonary viral load and increased the survival rate of H1N1-infected mice. Our data confirm the crucial role of c-Jun N terminal kinase in H1N1 virus replication and inflammatory responses in vivo. Hence, we speculate that SP600125 has a potential antiviral therapeutic benefit against IAV infection.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00705-021-05103-0.

In vitro and in vivo neuroprotective effects of cJun N-terminal kinase inhibitors on retinal ganglion cells.

BackgroundThe c-Jun N-terminal kinase (JNK) signaling pathway plays an important role in neuronal pathophysiology. Using JNK inhibitors, we examined involvement of the JNK pathway in cultured rat retinal ganglion cell (RGC) death and in mouse retinal ischemia/reperfusion (I/R) injury of the visual axis. The in vitro effects of JNK inhibitors were evaluated in cultured adult rat retinal cells enriched in RGCs. Retinal I/R was induced in C57BL/6J mice through elevation of intraocular pressure to 120 mmHg for 60 min followed by reperfusion. SP600125 was administered intraperitoneally once daily for 28 days. Phosphorylation of JNK and c-Jun in the retina was examined by immunoblotting and immunohistochemistry. The thickness of retinal layers and cell numbers in the ganglion cell layer (GCL) were examined using H&E stained retinal cross sections and spectral domain optical coherence tomography (SD-OCT). Retinal function was measured by scotopic flash electroretinography (ERG). Volumetric measurement of the superior colliculus (SC) as well as VGLUT2 and PSD95 expression were studied.ResultsJNK inhibitors SP600125 and TAT-JNK-III, dose-dependently and significantly (p < 0.05) protected against glutamate excitotoxicity and trophic factor withdrawal induced RGC death in culture. In the I/R model, phosphorylation of JNK (pJNK) in the retina was significantly (p < 0.05) increased after injury. I/R injury significantly (p < 0.05) decreased the thickness of retinal layers, including the whole retina, inner plexiform layer, and inner nuclear layer and cell numbers in the GCL. Administration of SP600125 for 28 days protected against all these degenerative morphological changes (p < 0.05). In addition, SP600125 significantly (p < 0.05) protected against I/R-induced reduction in scotopic ERG b-wave amplitude at 3, 7, 14, 21 and 28 days after injury. SP600125 also protected against the I/R-induced losses in volume and levels of synaptic markers in the SC. Moreover, the protective effects of SP600125 in the retina and SC were also detected even with only 7 days (Days 1–7 after I/R) of SP600125 treatment.ConclusionsOur results demonstrate the important role the JNK pathway plays in retinal degeneration in both in vitro and in vivo models and suggest that JNK inhibitors may be a useful therapeutic strategy for neuroprotection of RGCs in the retina.Electronic supplementary materialThe online version of this article (doi:10.1186/s13024-016-0093-4) contains supplementary material, which is available to authorized users.

Protective effect of SP600125, a JNK inhibitor, against nonalcoholic steatohepatitis

Protective effect of SP600125, a JNK inhibitor, against nonalcoholic steatohepatitis

Inhibition of c-Jun N-terminal kinase prevents blood–brain barrier disruption and normalizes the expression of tight junction proteins clautin-5 and ZO-1 in a rat model of subarachnoid hemorrhage

The c-Jun N-terminal kinase (JNK) proteins are encoded by three genes (JNK1, JNK2, and JNK3), giving rise to multiple isoforms via alternative splicing. JNK inhibition using a chemical inhibitor SP600125 confers neuroprotection in an animal model of subarachnoid hemorrhage (SAH). The aim of this study is to investigate whether the protective effects of SP600125 were associated with modulation of tight junction proteins including claudin-5 and ZO-1 and to define which JNK isoforms were involved in the early brain injury after SAH. Seventy-five male Sprague Dawley rats (weighing 300-350g) were randomly assigned to five groups (n = 15): (1) sham, (2) SAH, (3) SAH + DMSO (dimethyl sulfoxide), (4) SAH + 10mg/kg SP600125, and (5) SAH + 30mg/kg SP600125. SP600125 or DMSO was injected intraperitoneally 1 h before and 6h after the induction of SAH. Animals from all the groups were killed 24h after SAH, and brain tissues were dissected and subjected to electron microscopic examination, Western blot analysis, and histological evaluation. SP600125 pretreatment restored tight junctions and attenuated blood-brain barrier (BBB) disruption and cerebral edema after SAH, coupled with reduced apoptosis in the cerebral cortex. SP600125 exposure restored the reduced expression of both claudin-5 and ZO-1 following SAH and normalized the levels of JNK1 and JNK3. Our data demonstrate that the JNK signaling plays an important role in the regulation of tight junction proteins and BBB integrity, and thus represents a promising target against brain injuries after SAH.

Regulation of JNK activity in the apoptotic response of intestinal epithelial cells

We have studied apoptosis of gastrointestinal epithelial cells by examining the receptor-mediated and DNA damage-induced pathways using TNF-α and camptothecin (CPT), respectively. TNF-α requires inhibition of antiapoptotic protein synthesis by cycloheximide (CHX). CHX also results in high levels of active JNK, which are necessary for TNF-induced apoptosis. While CPT induces apoptosis, the increase in JNK activity was not proportional to the degree of apoptosis. Thus the mechanism of activation of JNK and its role in apoptosis are unclear. We examined the course of JNK activation in response to a combination of TNF-α and CPT (TNF + CPT), which resulted in a three- to fourfold increase in apoptosis compared with CPT alone, indicating an amplification of apoptotic signaling pathways. TNF + CPT caused apoptosis by activating JNK, p38, and caspases-8, -9, and -3. TNF-α stimulated a transient phosphorylation of JNK1/2 and ERK1/2 at 15 min, which returned to basal by 60 min and remained low for 4 h. CPT increased JNK1/2 activity between 3 and 4 h. TNF + CPT caused a sustained and robust JNK1/2 and ERK1/2 phosphorylation by 2 h, which remained high at 4 h, suggesting involvement of MEKK4/7 and MEK1, respectively. When administered with TNF + CPT, SP-600125, a specific inhibitor of MEKK4/7, completely inhibited JNK1/2 and decreased apoptosis. However, administration of SP-600125 at 1 h after TNF + CPT failed to prevent JNK1/2 phosphorylation, and the protective effect of SP-600125 on apoptosis was abolished. These results indicate that the persistent activation of JNK might be due to inhibition of JNK-specific MAPK phosphatase 1 (MKP1). Small interfering RNA-mediated knockdown of MKP1 enhanced TNF + CPT-induced activity of JNK1/2 and caspases-9 and -3. Taken together, these results suggest that MKP1 activity determines the duration of JNK1/2 and p38 activation and, thereby, apoptosis in response to TNF + CPT.

Protective effects of SP600125 in a diet-induced rat model of non-alcoholic steatohepatitis

Objective. To investigate the protective effect of SP600125, a selective c-Jun N-terminal kinase inhibitor, in a diet-induced rat model of non-alcoholic steatohepatitis (NASH). Material and methods. Sprague–Dawley rats were randomly divided into three groups: a normal control group (NC group), a high-fat model group (HF group) and an SP600125 treatment group (SP group). All animals were subjected to a percutaneous superior mesenteric vein retention catheter operation and fed with a standard diet for 10 days. The HF group was then fed with an HF diet and treated with dimethyl sulfoxide while the SP group was fed with an HF diet and treated with SP600125 (50 mg/kg) once per day. Results. Feeding rats with an HF diet established a model of NASH, with varying degrees of hepatic steatosis and hepatic inflammation. SP600125 treatment substantially decreased the incidence of insulin resistance, reduced lipotoxicity, inhibited oxidative stress and alleviated hepatocellular injury. Conclusions. SP600125 has the potential to remarkably attenuate steatosis and inflammation and may be a novel therapeutic drug against NASH.

Effect of JNK inhibition on cisplatin-induced renal damage

Cisplatin therapy is effective against many tumours, however, the nephrotoxicity of this drug is a dose-limiting factor. Apoptosis and necrosis of tubular cells and inflammatory events contribute to the cisplatin-induced nephrotoxicity. Cisplatin promotes increased production of reactive oxygen species, which can activate c-jun N-terminal kinase (JNK) that is a mediator of apoptosis and can lead to increased expression of proinflammatory mediators that could intensify the cytotoxic effects of cisplatin. In this study, we evaluated the effect that SP600125, a selective inhibitor of phosphorylated JNK (p-JNK), has on the renal damage caused by cisplatin use. A total of 33 male Wistar rats received SP600125 (15 mg/kg/day, s.c., diluted in polyethylene glycol) for 4 days. At 24 h after the first dose, those 33 rats, plus an additional 30, were injected with cisplatin (5 mg/kg, i.p.). In addition, 18 control rats were injected with saline, and 12 rats with polyethylene glycol. At 2 and 5 days after saline or cisplatin injection, blood and urine samples were collected for measurement of creatinine, sodium and potassium, and the kidneys removed for histological, immunohistochemical and Western blot studies. Cisplatin-treated rats presented higher plasma creatinine, as well as greater immunostaining for ED1 (macrophages/monocytes), p-JNK, apoptotic cells, and tubular cell necrosis in the renal cortices and outer medullae. The increase of p-JNK expression was also confirmed by Western blot analysis. All of these alterations were attenuated by treatment with SP600125. The protective effect of SP600125 on cisplatin-induced renal damage seems to be related to the reduction in the apoptotic cell death and to the restriction of renal inflammation.

Protective effects of SP600125 a new inhibitor of c-jun N-terminal kinase (JNK) and extracellular-regulated kinase (ERK1/2) in an experimental model of cerulein-induced pancreatitis

Extracellular regulated kinases (ERK1/2) and c-Jun N-terminal Kinases (JNK), are generally considered to play a key role in signal transduction pathways activated by a wide range of stimuli. We studied the effects of SP600125, a novel inhibitor of both JNK and ERK1/2, in male C57/BL6 mice given with an hyper-stimulating dose of cerulein (50 μg/kg for each of four injections at hourly intervals) to elicit secretagogue-induced pancreatitis. A control group received four intra-peritoneal injections of 0.9% saline at hourly intervals. Animals were randomized to receive either SP600125 (15 mg/kg i.p. administered 2h before and 30 min after the first injection of cerulein) or its vehicle (1 ml/kg of a 10% DMSO/NaCl solution). A group of animals was killed 30 minutes after the last cerulein injection to evaluate pancreatic JNK and ERK1/2 activation by Western Blot analysis. Another group was sacrificed 2 hours after the last cerulein injection to evaluate serum lipase and amylase levels, pancreas oedema, pancreatic content of Tumor Necrosis Factor-α (TNF-α) and Intercellular adhesion molecule-1 (ICAM-1) and the histological alterations. SP600125 inhibited almost totally JNK activation (90%) and partially ERK1/2 activation (45%), reduced the serum lipase and amylase levels and the degree of oedema, blunted the increased pancreatic content of TNF-α and ICAM-1 and protected against the histological damage. Our data confirm that both JNK and ERK1/2 activation plays a key role in acute pancreatitis and that SP600125 may represent a potential therapeutic approach to the treatment of patients at high risk of developing this life-threatening condition.