Novel Small Molecule Positive Allosteric Modulator SPAM1 Triggers the Nuclear Translocation of PAC1-R to Exert Neuroprotective Effects through Neuron-Restrictive Silencer Factor.

The neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) exerts effective neuroprotective activity through its specific receptor, PAC1-R. We accidentally discovered that as a positive allosteric modulator (PAM) of PAC1-R, the small-molecule PAM (SPAM1) has a hydrazide-like structure, but different binding characteristics, from hydrazide for the N-terminal extracellular domain of PAC1-R (PAC1-R-EC1). SPAM1 had a significant neuroprotective effect against oxidative stress, both in a cell model treated with hydrogen peroxide (H2O2) and an aging mouse model induced by D-galactose (D-gal). SPAM1 was found to block the decrease in PACAP levels in brain tissues induced by D-gal and significantly induced the nuclear translocation of PAC1-R in PAC1R-CHO cells and mouse retinal ganglion cells. Nuclear PAC1-R was subjected to fragmentation and the nuclear 35 kDa, but not the 15 kDa fragments, of PAC1-R interacted with SP1 to upregulate the expression of Huntingtin (Htt), which then exerted a neuroprotective effect by attenuating the binding availability of the neuron-restrictive silencer factor (NRSF) to the neuron-restrictive silencer element (NRSE). This resulted in an upregulation of the expression of NRSF-related neuropeptides, including PACAP, the brain-derived neurotrophic factor (BDNF), tyrosine hydroxylase (TH), and synapsin-1 (SYN1). The novel mechanism reported in this study indicates that SPAM1 has potential use as a drug, as it exerts a neuroprotective effect by regulating NRSF.

D-galactose protects the intestine from ionizing radiation-induced injury by altering the gut microbiome.

This article aims to investigate the protection of the intestine from ionizing radiation-induced injury by using D-galactose (D-gal) to alter the gut microbiome. In addition, this observation opens up further lines of research to further increase therapeutic potentials. Male C57BL/6 mice were exposed to 7.5 Gy of total body irradiation (TBI) or 13 Gy of total abdominal irradiation (TAI) in this study. After adjustment, D-gal was intraperitoneally injected into mice at a dose of 750 mg/kg/day. Survival rates, body weights, histological experiments and the level of the inflammatory factor IL-1ß were observed after TBI to investigate radiation injury in mice. Feces were collected from mice for 16S high-throughput sequencing after TAI. Furthermore, fecal microorganism transplantation (FMT) was performed to confirm the effect of D-gal on radiation injury recovery. Intraperitoneally administered D-gal significantly increased the survival of irradiated mice by altering the gut microbiota structure. Furthermore, the fecal microbiota transplanted from D-gal-treated mice protected against radiation injury and improved the survival rate of recipient mice. Taken together, D-gal accelerates gut recovery following radiation injury by promoting the growth of specific microorganisms, especially those in the class Erysipelotrichia. The study discovered that D-gal-induced changes in the microbiota protect against radiation-induced intestinal injury. Erysipelotrichia and its metabolites are a promising therapeutic option for post-radiation intestinal regeneration.

Beneficial effects of whey protein peptides on muscle loss in aging mice models.

Aging-related muscle loss is a hallmark of aging and is the cause of some negative outcomes. An optimized diet and supplements have a positive effect in slowing down the process of muscle loss. D-galactose(d-gal) has been used widely to develop aging model. This study explored the beneficial effects of whey protein peptides (WPPs) on sarcopenia in d-gal-induced aging mice. A total of 72 SPF male C57BL/6N mice were used in this study. Sixty mice were modeled by injected intraperitoneally with d-gal (100 mg/kg body weight for 6 weeks), and the other 12 mice were used as control, and injected with the same amount of normal saline. After 6 weeks, the modeled mice were randomly divided into the model control group, whey protein group (1.5 g/kg*bw), and three WPPs intervention groups (0.3 g/kg*bw, 1.5 g/kg*bw, 3.0 g/kg*bw), according to serum malondialdehyde (MDA) level. The test samples were orally given to mice by daily garaged. During the 30 days intervention period, the model control group, whey protein group, and WPPs group continued receiving intraperitoneal injections of d-gal, whereas the control group continued receiving intraperitoneal injections of normal saline. The results showed that WPPs could significantly improve the grip strength of aged mice. WPPs could significantly increase lean mass of aged mice and increase muscle weight of gastrocnemius and extensor digitorum longus. WPPs could significantly increase the level of insulin-like growth factor-1 (IGF-1) and reduce level of interleukin (IL)-1, IL-6, tumor necrosis factor-alpha (TNF-α) in serum. WPPs could affect the muscle fiber size in d-gal-induced aging mice. Its specific mechanism may be related to the activation of IGF-1/Akt/mTOR protein synthesis signaling pathway and reduction of the level of inflammation. These results indicate that WPPs can improve aging-related sarcopenia. Compared with whey protein, WPPs supplement seems a better form for sarcopenia.

Guiqi Dingnian Prescription Delays Senescence of Mouse Mesangial Cells by Regulating JAK2/STAT Pathway Activity / 中国实验方剂学杂志

Objective:To investigate the effects of Guiqi Dingnian prescription （GDP） on the expression of related molecules in Janus tyrosine kinase 2 （JAK2）/signal transducer and activator of transcription （JAK2/STAT） signaling pathway of <italic>D</italic>-galactose （<italic>D</italic>-gal）-induced senescent mesangial cells. Method:The senescent mouse mesangial cells induced by 10 g·L^-1 <italic>D</italic>-gal were continuously treated with 40 mg·L^-1GDP for three days. The senescence of the treated cells was determined by senescence-associated （SA）-<italic>β</italic>-gal staining. The cell cycle was detected by flow cytometry. The cell viability was analyzed using the cell counting kit-8 （CCK-8）. The mRNA expression levels of tumor necrosis factor-<italic>α</italic> （TNF-<italic>α</italic>）， interleukin-6 （IL-6）， nuclear transcription factor-<italic>κ</italic>B （NF-<italic>κ</italic>B）， and IL-1<italic>α</italic> were detected by real-time polymerase chain reaction （Real-time PCR）. The protein expression levels of STAT1， phosphorylated STAT1 （p-STAT1）， STAT3， and p-STAT3 in the JAK2/STAT signaling pathway were determined by Western blot. Result:CCK-8 results showed that the optimal concentration of GDP was 40 mg·L^-1. Compared with the blank group， the positive rate of SA-<italic>β</italic>-gal in the model group was significantly higher（<italic>P</italic><0.01）， the percentage of cells in G₀/G₁ phase was significantly increased（<italic>P</italic><0.05）， the percentage of cells in G₂/M and S phase was significantly decreased（<italic>P</italic><0.01）. The mRNA expression levels of TNF-<italic>α</italic>，IL-6，NF-<italic>κ</italic>B and IL-1<italic>α </italic>were significantly increased（<italic>P</italic><0.01）. Compared with the model group， the model + GDP group exhibited significantly decreased SA-<italic>β</italic>-gal-positive cells （<italic>P</italic><0.05）， reduced cells in the G₀/G₁ phase （<italic>P</italic><0.05）， increased cells in the G₂/M and S phases （<italic>P</italic><0.01）， and down-regulated TNF-<italic>α</italic>， IL-6， NF-<italic>κ</italic>B， and IL-1<italic>α </italic>mRNA expression （<italic>P</italic><0.05） and STAT1， p-STAT1， STAT3， and p-STAT3 protein expression （<italic>P</italic><0.05）. Conclusion:GDP delays the senescence of mouse mesangial cells possibly by down-regulating the expression of related molecules in the JAK2/STAT pathway.

The method and effect of rapid establishment of a mild cognitive impairment model.

BACKGROUND: To further the exploration of the pathogenesis of mild cognitive impairment (MCI), we aimed to determine the appropriate dose for a rapidly established MCI rat model using D-galactose (D-gal), with lasting cognitive effects. METHODS: In Experiment 1, we evaluated various D-gal concentrations (100-2,000 mg/kg/day), and determined that, compared with saline injections of the same volume. In Experiment 2, we evaluated the duration of the effect of 1,000 mg/kg/day D-gal injections for 1 week, with MWM testing initiated at 1 day, 1 month, and 3 months after completion of the injection regime in three model groups, respectively. RESULTS: In Experiment 1, D-gal injections at a concentration of 1,000 mg/kg/day for 1 week was adequate to induce a significantly worse Morris water maze (MWM) test performance and pathomorphologic changes in the hippocampus, with MWM testing initiated 1 day after completion of the injection regime. In Experiment 2, Before modeling, the overall condition (fur, mental state, foraging behavior, and activity level), body weight, swimming speed, and swimming time did not significantly differ between the control (saline injections) and model groups (D-gal injections). After modeling, MWM test performance was considerably worse (longer escape latencies and fewer platform crossings within 90 seconds) in the model groups than in the control group, without significant differences among model groups. Furthermore, movement trajectories were similar among model groups. CONCLUSIONS: These results demonstrate that subcutaneous injections of D-gal 1,000 mg/kg/day for 1 week produce changes consistent with the characteristics and pathological processes of MCI. Thus, high-dose D-gal injection allows the rapid establishment of an MCI model that is effective and sustainable.

[Effect of SIRT1 on delay of D-gal-induced premature ovarian failure in mice with ginsenoside Rg_1].

To explore the effect of slient mating type information regulation 2 homolog 1(SIRT1) on the delay of D-galactose(D-gal) induced premature ovarian failure in mice with ginsenoside Rg_1(Rg_1). Fifty-four female SPF BALB/c mice were randomly divided into PBS group, D-gal group, and Rg_1 group. In the D-gal group, D-galactose(200 mg·kg~(-1)·d~(-1)) was injected subcutaneously into the neck and back for 42 days. In the PBS group, the equal amount of phosphate buffered saline(PBS) was injected into the neck and back for 42 days. In addition to the therapy of D-gal group, Rg_1 group was given Rg_1(20 mg·kg~(-1)·d~(-1)) through the intraperitoneal injection on the 15 th day for 28 days. At the same time, the D-gal group and the PBS group were also given an equal amount of PBS through hintraperitoneal injection on the 15 th day for 28 days. The changes in body weight and ovarian weight coefficient of mice were detected. Expressions of estradiol 2(E_2), luteinizing hormone(LH), superoxide dismutase(SOD), catalase(CAT) and follicle-stimulating hormone(FSH) in peripheral blood were detected. Morphological changes of ovaries were detected by HE staining. Changes in expression of aging regulator SIRT1 were detected by fluorescent quantitative PCR and Western blot. The results showed that compared with the PBS group, the body weight growth rate of the D-gal group was significantly slowed, the ovarian weight coefficient was decreased, the serum levels of E_2, LH, SOD, CAT were significantly reduced, and FSH was significantly increased. After the administration with Rg_1, the body weight growth rate, ovarian weight coefficient, serum levels of E_2, LH, SOD, and CAT in the mice were higher than those in the D-gal group, while FSH was lower than those in the D-gal group. HE staining showed that the follicular morphology and structure of the PBS group were normal; the number of follicles in the D-gal group was reduced, the corpus luteum was vacuolated, and the number of atretic follicles was increased. Compared with the D-gal group, the number of follicles in the Rg_1 group was increased, whereas the number of corpus luteum was decreased. Compared with the PBS group, SIRT1 expression was down-regulated in the D-gal group, while SIRT1 expression was up-regulated in the Rg_1 group compared with the D-gal group. The results suggested that Rg_1 could delay D-gal-induced premature ovarian failure in a mouse model of premature ovarian failure, and SIRT1 played an important role in this.

Neuroprotective effect of three caffeic acid derivatives via ameliorate oxidative stress and enhance PKA/CREB signaling pathway.

This study was conducted to elucidate the neuroprotective effect of caffeic acid phenethyl ester (CAPE), (R)-2-Hydroxy-3-(3,4-dihydroxyphenyl) propionic acid (Danshensu) and Curcumin, three caffeic acid derivatives which are contained in fruits, grains and certain dietary supplements. Our results showed that these compounds significantly attenuated H2O2-induced toxicity in PC12 cells in a dose-dependent manner. Furthermore, these compounds significantly improved the behavioral performance of d-gal-treated mice in both step-down avoidance test and Morris water maze test. Biochemical examination and western blot analysis showed that these compounds could ameliorate oxidative stress and facilitate activation of the protein kinase A (PKA)-cyclic AMP response element-binding protein (CREB) pathway. Its beneficial effects may partly relate to enhancing the activity of endogenous antioxidant enzymes and modulating the PKA/CREB signaling pathway. Furthermore, our results also indicated that the presence of 3, 4-dihydroxyphenyl groups in A ring may enhance their neuroprotective activity.

Glutamine synthetase plays a role in D-galactose-induced astrocyte aging in vitro and in vivo.

Astrocytes play multiple roles in physiological and pathological conditions in brain. However, little is known about the alterations of astrocytes in age-related changes, and few aging models of the astrocytes in vitro have been established. Therefore, in the present study, we used d-galactose (D-Gal) to establish astrocyte aging model to explore the alterations of astrocytes in brain aging. We also used (1)H nuclear magnetic resonance ((1)H NMR) spectra to verify the metabolic changes in the cerebral cortex of mice injected with D-gal. The results showed that D-gal (55mM) treatment for 1 week induced senescence characteristics in cultured cortical astrocytes. Real-time PCR and western blot analysis showed that the levels of glutamine synthetase (GS) mRNA and protein were strikingly decreased in the cultured senescent astrocytes, and the senescent astrocytes showed less resistance to the glutamate-induced gliotoxicity. The impairments of glutamate-glutamine cycle and astrocytes were also found in the cerebral cortex of mice treatment with D-gal (100mg/kg) for 6 weeks, and the level of GS mRNA was also found to be reduced markedly, being consistent with the result obtained from the senescent astrocytes in vitro. These results indicate that astrocyte may be the predominant contributor to the pathogenic mechanisms of D-gal-induced brain aging in mice, and GS might be one of the potential therapeutic targets of the aged brain induced by D-gal.

Effect of Pyrroloquinoline Quinone on Aging of Rat Hippocampal Neurons in Vitro / 中国康复理论与实践

@#Objective To investigate the effect of pyrroloquinoline quinone(PQQ) on the aging of rat hippocampal neurons induced by D-galactose(D-gal).Methods Hippocampal neurons were cultured in vitro.The aging of the hippocampal neurons was induced by high dose D-gal,PQQ protection were used 30 min before D-gal.The metamorphosis of hippocampal neurons was observed under the microscope.The contents of free radical was measured.The incidence of apoptosis of hippocampus cells was tested with the flow cytometry.The expression of Bax was detected with immunohistochemical staining.Results After the cells cultured in vitro exposed to D-gal,the content of free radical and the expression of Bax of the hippocampal neurons increased.After pretreatment of the cultured neurons with PQQ,the contents of free radical and the expression of Bax decreased,the survival of hippocampal neurons increased.Conclusion PQQ may slow the aging progress of hippocamal neurons induced by D-gal.