Cerebral ischemia reduces expression of Hs1-associated protein X-1 (Hax-1) in mouse brain

Targeting NLRP3 signaling by a novel-designed sulfonylurea compound for inhibition of microglial inflammation

The nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (NLRP3) inflammasome plays an important role in microglia-mediated inflammation. Dysregulation of NLRP3 signaling results in microglial activation and triggers inflammatory responses contributing to the development of neurological disorders including ischemic stroke, schizophrenia, Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). Inhibition of the NLRP3-linked inflammatory pathways reduces microglia-induced inflammation and is considered as a promising therapeutic approach for neuro-inflammatory diseases. In the present study, we report the development of AMS-17, a rationally-designed tertiary sulfonylurea compound for inhibition of inflammation in microglia. AMS-17 inhibited expression of the NLRP3, and its downstream components and cytokines such as caspase-1, tumor necrosis factor-α (TNF-α), IL-1β and inducible nitric oxide synthase (iNOS). It also suppressed lipopolysaccharide (LPS)-induced N9 microglial cell phagocytosis in vitro and activation of the microglia in mouse brain in vivo. Together, these results provide promising evidences for the inhibitory effects of AMS-17 in inflammation. This proof-of-concept study provides a new chemical scaffold, designed with the aid of pharmacophore modeling, with NLRP3 inhibitory activity which can be further developed for the treatment of inflammation-associated neurological disorders.

Neuroprotective roles of HAX-1 in ischemic neuronal injury

Hematopoietic cell-specific protein 1 associated protein X-1 (HAX-1) is a novel mitochondrial protein that regulates oxidative stress-induced apoptosis. However, the roles of HAX-1 in ischemic neuronal injury have not been thoroughly elucidated. In this study, the expression and roles of HAX-1 after ischemic stress were investigated using in vivo and in vitro models. The effect of oxidative stress on the regulation of HAX-1 was examined using knockout mice lacking nicotinamide-adenine dinucleotide phosphate oxidase 2 (NOX2), which is a major source of reactive oxygen species (ROS) after cerebral ischemia. Male C57BL/6 J mice were subjected to transient forebrain ischemia induced by 22-min occlusion of the bilateral common carotid arteries, and striatum samples were analyzed. For in vitro ischemic experiments, oxygen and glucose deprivation (OGD) in a rat pheochromocytoma cell line was utilized. Western blotting and immunofluorescence analysis revealed HAX-1 expression in neuronal mitochondria, which was significantly decreased after ischemia in vivo and in vitro. In NOX2 knockout mice, ischemia-induced decrease in HAX-1 expression and ischemic neuronal injury was significantly alleviated compared to those in wild-type mice. Inhibition of HAX-1 using small interfering RNA significantly increased injury in cultured cells after OGD. These findings suggest that HAX-1 has a neuroprotective effect against ischemic neuronal injury, and downregulation of HAX-1 by NOX2-produced ROS induces apoptosis after cerebral ischemia.

HAX1 enhances the survival and metastasis of non-small cell lung cancer through the AKT/mTOR and MDM2/p53 signaling pathway

Background

HS‐1‐associated protein‐1 (HAX1) has been reported to be overexpressed in non‐small cell lung cancer (NSCLC) tissues. However, the underlying mechanism of HAX1 in NSCLC has not previously been demonstrated. The present study investigated the role and underlying mechanism of HAX1 in NSCLC.

Methods

The HAX1 expression were confirmed in NSCLC tissues through TCGA database and qRT‐PCR. Moreover, we performed qRT‐PCR, Western blotting, Transwell assays, TUNEL assays and so on to evaluate the role of HAX1 in A549 and H1299 cell lines.

Results

mRNA expression of HAX1 was overexpressed in NSCLC tissues compared to adjacent normal tissues according to The Cancer Genome Atlas (TCGA) database. QRT‐PCR assays showed that HAX1 mRNA expression was upregulated in NSCLC tissues. The high HAX1 mRNA levels were found to be positively associated with tumor size, TNM stage and lymphatic metastasis. Silencing of HAX1 promoted apoptosis and reduced invasion of A549 and H1299 cells by inhibiting the AKT/mTOR and MDM2/P53 signal pathway. AKT agonist SC79 could inhibit apoptosis and promote proliferation, migration and invasion of A549 and H1299 cells transfected with si‐HAX1.

Conclusions

The present study provided a better understanding of HAX1 mechanism in NSCLC and potential therapeutic target for NSCLC.

KDM4B plays an important role in mitochondrial apoptosis by upregulating HAX1 expression in colorectal cancer

Histone methyltransferases and demethylases regulate transcription by altering the epigenetic marks on histones in tumorigenesis. Members of the histone lysine(K)-specific demethylase 4 (KDM4) family are dysregulated in several types of cancer. Here, we report a novel role for KDM4B in mitochondrial apoptosis. In this study, we demonstrate that KDM4B is overexpressed in colorectal cancer (CRC) tissues. Decreased expression of KDM4B significantly promoted apoptosis of CRC cell lines. Moreover, our data indicate that HAX1 is required for KDM4B-mediated mitochondrial apoptosis. The transcription of HAX1 was directly activated by KDM4B. We also show that HAX1 is overexpressed in CRC tissues and is positively correlated with KMD4B expression. Collectively, we demonstrate that KDM4B may play an important role in mitochondrial apoptosis and represent a potential therapeutic cancer target in CRC.

Alterations in the expression of Hs1-associated protein X-1 in the rat retina after optic nerve crush

HS-1-associated protein X-1 (Hax-1) has been suggested to be expressed in various rodent and human tissues. Accumulating evidence has demonstrated that Hax‑1 exerts an anti‑apoptotic effect in neurological diseases. Furthermore, it has also been reported that Hax‑1 interacts with various apoptosis‑associated proteins, including high temperature-regulated A2 (HtrA2) and caspase‑3. Previous studies have indicated that abnormal expression of Hax‑1 may be associated with the development of the nervous system and with the pathophysiology of neurological diseases, including traumatic brain injury and cerebral ischemia. The present study reported temporal‑spatial patterns of Hax‑1 in rat retina following optic nerve crush (ONC). Using western blotting and double‑immunofluorescence, significant upregulation of Hax‑1 was observed in retinal ganglion cells (RGCs) in the retina following ONC. Increased Hax‑1 expression was demonstrated to be accompanied by upregulation of active‑caspase‑3 and HtrA2 following ONC. In addition, Hax-1 co‑localized with active caspase‑3 and HtrA2 in RGCs following ONC. Terminal deoxynucleotidyl transferase‑mediated biotinylated-dUTP nick‑end labeling staining suggested that Hax‑1 was involved in RGC apoptosis following ONC. Thus, these results suggested that Hax‑1 may participate in regulating RGC apoptosis via interacting with caspase‑3 and HtrA2 following ONC.