Dihydroartemisinin suppresses renal fibrosis in mice by inhibiting DNA-methyltransferase 1 and increasing Klotho.

Renal fibrosis is an unavoidable end result of all forms of progressive chronic kidney diseases (CKD). Discovery of efficacious drugs against renal fibrosis is in crucial need. In a preliminary study we found that a derivative of artemisinin, dihydroartemisinin (DHA), exerted strong renoprotection, and reversed renal fibrosis in adenine-induced CKD mouse model. In this study we investigated the anti-fibrotic mechanisms of DHA, particularly its specific target in renal cells. Renal fibrosis was induced in mice by unilateral ureteral obstruction (UUO) or oral administration of adenine (80 mg · kg-1), the mice received DHA (30 mg · kg-1 · d-1, i.g.) for 14 or 21 days, respectively. We showed that DHA administration markedly attenuated the inflammation and fibrotic responses in the kidneys and significantly improved the renal function in both the renal fibrosis mouse models. In adenine-treated mice, DHA was more effective than 5-azacytidine against renal fibrosis. The anti-fibrotic effects of DHA were also observed in TGF-ß1-treated HK-2 cells. In order to determine the target protein of DHA, we conducted pull-down technology coupled with shotgun proteomics using a small-molecule probe based on the structure of DHA (biotin-DHA). As a results, DNA methyltransferase 1 (DNMT1) was identified as the anti-fibrotic target of DHA in 3 different types of renal cell lines (HK-2, HEK293 and 3T3). We demonstrated that DHA directly bound to Asn 1529 and Thr 1528 of DNMT1 with a Kd value of 8.18 µM. In primary mouse renal tubular cells, we showed that DHA (10 µM) promoted DNMT1 degradation via the ubiquitin-proteasome pathway. DHA-reduced DNMT1 expression effectively reversed Klotho promoter hypermethylation, which led to the reversal of Klotho protein loss in the kidney of UUO mice. This subsequently resulted in inhibition of the Wnt/ß-catenin and TGF-ß/Smad signaling pathways and consequently conferred renoprotection in the animals. Knockdown of Klotho abolished the renoprotective effect of DHA in UUO mice. Our study reveals a novel pharmacological activity for DHA, i.e., renoprotection. DHA exhibits this effect by targeting DNMT1 to reverse Klotho repression. This study provides an evidence for the possible clinical application of DHA in the treatment of renal fibrosis.

Ligustrazine Attenuates Hyperhomocysteinemia-induced Alzheimer-like Pathologies in Rats.

Ligustrazine, an alkaloid extracted from the traditional Chinese herbal medicine Ligusticum Chuanxiong Hort, has been clinically applied to treat the cerebrovascular diseases. Hyperhomocysteinemia (Hhcy) is an independent risk factor for Alzheimer's disease (AD). Memory deficits can be caused by Hhcy via pathologies of AD-like tau and amyloid-ß (Aß) in the hippocampus. Here, we investigated whether homocysteine (Hcy) can induce AD-like pathologies and the effects of ligustrazine on these pathologies. The Hcy rat model was constructed by 14-day Hcy injection via vena caudalis, and rats were treated with daily intragastric administration of ligustrazine at the same time. We found that the pathologies of tau and Aß were induced by Hcy in the hippocampus, while the Hcy-induced tau hyperphosphorylation and Aß accumulation could be markedly attenuated by simultaneous ligustrazine treatment. Our data demonstrate that ligustrazine may be used as a promising neuroprotective agent to treat the Hcy-induced AD-like pathologies.

Hydrogen sulfide enhances adult neurogenesis in a mouse model of Parkinson's disease.

Hydrogen sulfide (H2S) is regarded to be a protectant against diseases of the central nervous system and cardiovascular system. However, the mechanism by which H2S elicits neuroprotective effects in the progression of Parkinson's disease (PD) remains unclear. To investigate the role of H2S in delaying the pathological process of PD, we used the most common sodium hydrosulfide (NaHS) as an H2S donor and established a mouse model of PD induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid (MPTP/p) in the present study. Our results show that H2S reduced neuronal loss during the progression of PD. Notably, we found that H2S exhibited protective effects on dopaminergic neurons. Excitingly, H2S also increased the proliferation of neural stem cells in the subventricular zone. Next, we evaluated whether the neuroprotective effects of H2S on dopaminergic neurons in PD are dependent on adult nerve regeneration by treating primary adult neural stem cells cultured ex vivo with 1-methyl-4-phenylpyridine. Our results show that H2S could prevent nerve injury induced by 1-methyl-4-phenylpyridine, promote the growth of neurospheres, and promote neurogenesis by regulating Akt/glycogen synthase kinase-3ß/ß-catenin pathways in adult neural stem cells. These findings confirm that H2S can increase neurogenesis in an adult mouse model of PD by regulating the Akt/glycogen synthase kinase-3ß/ß-catenin signaling pathway. This study was approved by the Animal Care and Use Committee of Nanjing Medical University, China (IACUC Approval No. 1601153-3).

High-frequency transcranial magnetic stimulation protects APP/PS1 mice against Alzheimer's disease progress by reducing APOE and enhancing autophagy.

INTRODUCTION: The repetitive transcranial magnetic stimulation (rTMS) has clinically wide application prospect of psychiatry and neuroscience, for its painless, noninvasive, and high efficiency. So far, rTMS has been used in the treatment of Alzheimer's disease (AD) but the underlying mechanism is not clear. METHODS AND RESULTS: The APP/PS1 mice at 3-month-old were treated by 5 Hz high-frequency (HF) rTMS for two weeks. After rTMS treatment, the AD-like cognitive impairments of APP/PS1 mice were investigated subsequently, and molecular mechanisms underlying was further explored. The study showed that the 2-week rTMS at 5Hz frequency improved cognitive impairments and AD-like pathology (including a decrease in p-Tau, APP, Aß, and PP2A expression) of APP/PS1 mice. Although BDNF-TrkB signaling was significantly enhanced, no differences of SYN, PSD95 and p-AKT were observed in the brain of APP/PS1 mice. On the contrary, the LC3Ⅱ/LC3Ⅰ ratio was elevated with a significant reduction of ApoE and p62 in mice. CONCLUSIONS: rTMS exerts a potentially protective role in the prevention and treatment of AD by reducing ApoE expression and promoting autophagic flux, which provides a new insight into the mechanism of rTMS.

Discovery of novel pyrrolo-pyridine/pyrimidine derivatives bearing pyridazinone moiety as c-Met kinase inhibitors.

In continue to our previous research, eight series of pyrrolo[2,3-b]pyridine and pyrrolo[2,3-d]pyrimidine derivatives bearing pyridazinone moiety were designed, synthesized, and the in vitro antitumor activity was evaluated against four cancer cell lines (A549, HepG2, MCF-7 and PC-3). Some selected compounds (22f, 22g, 26c and 26e) were evaluated for the activity against c-Met kinase, and according to the results of kinase inhibitory activity, the compound 22g was further evaluated for other four tyrosine kinases (Flt-3, VEGFR-2, c-Kit and EGFR) to test the enzyme-based selectivity. The most promising compound 22g showed excellent activity than lead compound Foretinib against A549, HepG2, MCF-7 and PC-3 cell lines, with the IC50 values of 2.19 ± 0.45 µM, 1.32 ± 0.26 µM, 6.27 ± 1.04 µM and 4.63 ± 0.83 µM. The structure-activity relationships (SARs) and docking studies indicated that the pyrrolo[2,3-b]pyridine derivatives bearing 4-oxo-pyridazinone moiety was superior to the pyrrolo[2,3-d]pyrimidine derivatives bearing 6-oxo-pyridazinone moiety. What's more, the target compounds modified with X and Y (X = H, Y = H) were favorable to the activity. And electron drawing groups (EWGs) of 4-Cl-3CF3 on the aryl group show the best activity.

Kir6.1 knockdown aggravates cerebral ischemia/reperfusion-induced neural injury in mice.

BACKGROUND AND PURPOSE: ATP-sensitive potassium (K-ATP) channels couple energy metabolism with electric activity, which play important roles in brain diseases including stroke. However, the impacts of Kir6.1-containing K-ATP channels that mainly expressed on glia in stroke remain unclear. METHODS AND RESULTS: In this study, we found that expression of Kir6.1 was significantly decreased in the ischemic brain area of C57BL/6J mice after 1-h middle cerebral artery occlusion (MCAO) and 24-h reperfusion. Then, we subjected Kir6.1 heterozygote knockout (Kir6.1(+/-) ) mice to cerebral ischemia/reperfusion (I/R) injury and found that Kir6.1(+/-) mice exhibited exacerbated neurological disorder and enlarged infarct size, companied by glial over-activation and blood-brain barrier (BBB) damages. Furthermore, we showed that Kir6.1 knockdown aggravated endoplasmic reticulum (ER) stress and thereby increased the levels of proinflammatory factors tumor necrosis factor-α and interleukin-1ß (TNF-α and IL-1ß) in mouse brain. CONCLUSIONS: Our findings reveal that Kir6.1 knockdown exacerbates cerebral I/R-induced brain damages via increasing ER stress and inflammatory response, indicating that Kir6.1-containing K-ATP channels may be a potential therapeutic target for stroke.