Effect of Sutellarin on Neurogenesis in Neonatal Hypoxia–Ischemia Rat Model: Potential Mechanisms of Action

p75ECD-Fc reverses neonatal hypoxic-ischemic encephalopathy-induced neurological deficits and inhibits apoptosis associated with Nestin

A recent study has introduced a recombinant fusion protein, consisting of the extracellular domain (ECD) of p75 and the Fc fragment of human immunoglobulin IgG1 (p75ECD-Fc), as a multifaceted agent within the nervous system. This research aimed to assess the effects of p75ECD-Fc on neuronal growth and the restoration of neurological functions in rats afflicted with neonatal hypoxic-ischemic encephalopathy (NHIE). In vitro analyses revealed that 1 μM p75ECD-Fc treatment markedly increased cell viability and facilitated neurite outgrowth in neurons exposed to oxygen-glucose deprivation (OGD). Subsequent in vivo studies determined that a dose of 78.6 μg/3 μl of p75ECD-Fc significantly mitigated brain damage and both acute and long-term neurological impairments, outperforming the therapeutic efficacy of hypothermia, as evidenced through behavioral assessments. Additionally, in vivo immunostaining showed that p75ECD-Fc administration enhanced neuronal survival and regeneration, and reduced astrocytosis and microglia activation in the cortex and hippocampus of NHIE rats. A noteworthy shift from A1 to A2 astrocyte phenotypes and from M1 to M2 microglia phenotypes was observed after p75ECD-Fc treatment. Furthermore, a co-expression of the p75 neurotrophin receptor (p75NTR) and Nestin was identified, with an overexpression of Nestin alleviating the neurological dysfunction induced by NHIE. Mechanistically, the neuroprotective effects of p75ECD-Fc, particularly its inhibition of neuronal apoptosis post-OGD, may be attributed to Nestin. Taken together, these results highlight the neuroprotective and anti-inflammatory effects of p75ECD-Fc treatment through the modulation of glial cell phenotypes and the Nestin-mediated inhibition of neuronal apoptosis, positioning it as a viable therapeutic approach for NHIE.

Scutellarin Attenuates Microglia Activation in LPS-Induced BV-2 Microglia via miRNA-7036a/MAPT/PRKCG/ERK Axis

Scutellarin is an herbal agent which can exert anti-neuroinflammatory effects in activated microglia. However, it remains uncertain if it can inhibit microglia-mediated neuroinflammation by regulating miRNAs. This study sought to elucidate the upstream regulatory mechanisms by endogenous microRNAs and its target gene in activated microglia in lipopolysaccharide (LPS)-induced BV-2 microglia. Results show that scutellarin suppressed the expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and inducible nitric oxide synthase (iNOS) significantly in LPS-stimulated BV-2 microglia. As with the results of miRNAs function classification in vitro, the expression levels of mir-7036a-5p are upregulated in LPS-activated BV-2 microglia, but are downregulated by scutellarin. Rescue experiments indicated that mir-7036a-5p is a pro-inflammatory factor in activated BV-2 microglia. mir-7036a-5p agomir promoted the expression of phosphorylated tau proteins (p-tau), protein kinase C gamma type (PRKCG), extracellular regulated protein kinases (ERK1/2), but the is reversed by mir-7036a-5p antagomir in vitro. It is shown here that mir-7036a-5p is involved in microglia-mediated inflammation in LPS-induced BV-2 microglia. More important is the novel finding that scutellarin mitigated microglia inflammation by down-regulating the mir-7036a-5p/MAPT/PRKCG/ERK signaling pathway.

Suppression of SAMSN1 contributes to neuroprotection in neonatal rats suffering from hypoxic-ischemic encephalopathy injury

This article aims to detect the effect of SAM domain, SH3 domain, and nuclear localization signal 1 (SAMSN1) in neonatal rats with neurological dysfunction induced by hypoxia and ischemia (HI). The HI model was created using 7-day postnatal rats. Zea-longa score was utilized to validate the neurological injury after HI. Then, the differentially expressed genes (DEGs) were detected by gene sequencing and bioinformatics analysis methods. The oxygen and glucose deprivation (OGD) models were established in the SY5Y cells and fetal human cortical neurons. In addition, SAMSN1-small interfering RNA, methyl thiazolyl tetrazolium assay, and cell growth curve were employed to evaluate the cell viability variation. Obviously, Zea-longa scores increased in rats with HI insult. Subsequently, SAMSN1 was screened out, and it was found that SAMSN1 was strikingly upregulated in SY5Y cells and fetal neurons post-OGD. Interestingly, we found that SAMSN1 silencing could markedly enhance cell viability and cell growth after OGD. These data suggested that downregulation of SAMSN1 may exert a neuroprotective effect on damaged neurons after HI by improving cell viability and cell survival, which provides a potential theoretical basis for clinical trials in the future to treat neonatal hypoxic-ischemic encephalopathy.

P75 neurotrophin receptor as a therapeutic target for drug development to treat neurological diseases

The interaction of neurotrophins with their receptors is involved in the pathogenesis and progression of various neurological diseases, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, spinal cord injury and acute and chronic cerebral damage. The p75 neurotrophin receptor (p75NTR) plays a pivotal role in the development of neurological dysfunctions as a result of its high expression, abnormal processing and signalling. Therefore, p75NTR represents as a vital therapeutic target for the treatment of neurodegeneration, neuropsychiatric disorders and cerebrovascular insufficiency. This review summarizes the current research progress on the p75NTR signalling in neurological deficits. We also summarize the present therapeutic approaches by genetically and pharmacologically targeting p75NTR for the attenuation of pathological changes. Based on the evolving knowledge, the role of p75NTR in the regulation of tau hyperphosphorylation, Aβ metabolism, the degeneration of motor neurons and dopaminergic neurons has been discussed. Its position as a biomarker to evaluate the severity of diseases and as a druggable target for drug development has also been elucidated. Several prototype small molecule compounds were introduced to be crucial in neuronal survival and functional recovery via targeting p75NTR. These small molecule compounds represent desirable agents in attenuating neurodegeneration and cell death as they abolish activation-induced neurotoxicity of neurotrophins via modulating p75NTR signalling. More comprehensive and in-depth investigations on p75NTR-based drug development are required to shed light on effective treatment of numerous neurological disorders.

Knockdown of interleukin-6 plays a neuroprotective role against hypoxia-ischemia in neonatal rats via inhibition of caspase 3 and Bcl-2-associated X protein signaling pathway

This study aimed to investigate the role of interleukin-6 (IL-6) in the pathogenesis of neonatal hypoxic-ischemic encephalopathy (NHIE). Sprague-Dawley (SD) rats were used for the establishment of hypoxic-ischemic (HI) model. The Zea-Longa scoring was used to evaluate the extent of the neurological deficits. Triphenyl tetrazolium chloride (TTC) staining was used to measure the volume of infarction in the brain following HI protocol. The expression of IL-6 in the cortex and/or hippocampus at multiple time points after HI was examined by immunohistochemistry, western blotting and immunofluorescence. Moreover, small interfering RNAs (siRNA) were used to inhibit the expression of IL-6 in-vitro and in-vivo, and the concomitant expression of the Bcl-2 associated X protein (BAX) and caspase 3 was also measured. HI induced a significant brain damage, and these pathological changes were accompanied by IL-6 upregulation which was found localized in cortical neurons. The inhibition of IL-6 expression fostered neuronal and axonal growth, and a reduction in cellular apoptosis in cortical neuronal cultures, and cortex and hippocampus of neonatal rats. The expression of apoptotic markers such as BAX and caspase 3 was closely associated with IL-6. Downregulation of IL-6 could ameliorate HI-induced deficiencies by mediating the expression of caspase 3 and BAX.

AQP4 knockout promotes neurite outgrowth via upregulating GAP43 expression in infant rats with hypoxic-ischemic brain injury

Neonatal hypoxic-ischemic encephalopathy (NHIE) induces severe cerebral damage and neurological dysfunction, with seldom effective therapy. Aquaporin-4 (AQP4) is involved in aggravating brain damage induced by NHIE. This study aimed to investigate the role of AQP4 underlying the pathogenesis of NHIE. Neonatal Sprague-Dawley rats were used to establish neonatal hypoxic-ischemic (HI) models, and the expression of AQP4 in the cortex, hippocampus, and lung tissues was detected by real-time quantitative polymerase chain reaction as well as Western blot. Primary cortical neurons were cultured for the oxygen-glucose deprivation (OGD) model, and siRNA was used to silence the expression of AQP4. Immunostaining of Tuj1 was performed to observe the axonal growth. CRISPER/Cas9 technology was used to knock out AQP4. The results demonstrated that AQP4 was upregulated in the cortex, hippocampus, and lung tissues in neonatal rats with HI and OGD neurons. Besides, silencing AQP4 promoted axonal growth of OGD neurons, and AQP4 knockout notably improved long-term neurobehavioral impairment. Furthermore, GAP43 was found closely correlated with AQP4 via GeneMANIA prediction. Significant downregulation of GAP43 was induced in OGD neurons, while AQP4 knockout markedly upregulated its expression in rats. This indicated that the depletion of AQP4 may enhance axonal regeneration and promote the long-term neurobehavioral recovery associated with the upregulation of GAP43 expression.

Differences between cultured cortical neurons by trypsin and papain digestion

The objective of this study was to compare the efficiency of trypsin and papain in neuronal digestion and determine which enzyme is more efficient. Cortical tissues were obtained from Sprague-Dawley (SD) rats. According to the different digestive enzymes, the samples were divided into the trypsin group and the papain group. After being digested by each of the two enzymes, cortical neurons were collected from the samples. Then, the morphology of the cortical neurons was determined. Moreover, the cortical neurons were transfected with the negative control (NC) lentivirus. The transfection efficiency and morphology were determined and compared. Compared with the papain group, cortical neurons in the trypsin group were more in number, had larger cell size, had longer axonal length, and had fewer impurities. The transfection efficiency of the trypsin group (57.77%) was higher than that of the papain group (53.83%). The morphology of neurons that was displayed showed that the cell body of most neurons shrank and became smaller, and the axis mutation became shorter and less in the papain group 6 days after transfection with the NC lentivirus. Trypsin is more efficient in digesting neurons because the neurons digested by this enzyme are more in number, have a larger cell body, longer axons, and greater transfection efficiency.

Glycosidic flavonoids and their potential applications in cancer research: a review

Purpose of review

Every year, the cancer patient registry increases, and the leading cause of death in a global context. Plant-based molecules are gaining attention in cancer research due to the side effects of chemotherapy. A glycosidic derivative of flavonoid (GDF) plays a significant role in cancer proliferation mechanisms. GDF inhibits cell proliferation by elevating the expression of apoptotic proteins, altering the expression of nuclear factor-kappa B (NF- κB), and decreasing mitochondrial membrane potential (Δψm) in cancer cells.

Recent findings

Reported studies on the flavonoids orientin, vitexin, prunetionoside, chrysin, and scutellarein increased attention and are being widely investigated for their potential role in different parts of cancer research. Prunetionoside is a flavonoid with high cytotoxic potential and capable of inducing necroptosis in AGS gastric cancer cells. Similarly, scutellarein is a flavonol, induces an extrinsic apoptotic pathway and downregulates the expression level of cyclin proteins in HepG2 liver cancer cells. Vitexin is reported to be capable of deregulating the expression levels of p-Akt, p-mTOR, and p-PI3K in A549 lung cancer cells. Orientin inhibits IL-8 expression and invasion in MCF-7 breast cancer cells by suppressing MMP-9 in the presence of TPA via STAT3/AP-1/ERK/PKCα-mediated signaling pathways. It also induces mitochondria-mediated intrinsic apoptosis and G0/G1 cell cycle arrest in HT29 colon cancer cells. Chrysin is a flavonoid present in honey that has been shown to play an important role in cervical and colon cancer by suppressing the AKT/mTOR/PI3K pathway and increasing ROS accumulation, LDH leakage, respectively.

Panax notoginseng saponin attenuates the hypoxic-ischaemic injury in neonatal rats by regulating the expression of neurotrophin factors

Neonatal hypoxic-ischaemic (HI) injury is a serious complication of neonatal asphyxia and the leading cause of neonatal acute death and chronic neurological injury, and the effective therapeutic method is lacking to improve patients' outcomes. We reported in this study that panax notoginseng saponin (PNS) may provide a treatment option for HI. HI model was established using neonatal Sprague-Dawley rats and then intraperitoneally injected with different dosage of PNS, once a day for 7 days. Histological staining and behavioural evaluations were performed to elucidate the pathological changes and neurobehavioural variation after PNS treatment. We found PNS administration significantly reduced the infarct volume of brain tissues and improved the autonomous activities of neonatal rats, especially with higher dosage. PNS treatment at 40 mg/kg reduced neuronal damage, suppressed neuronal apoptosis and depressed astroglial reactive response. Moreover, the long-term cognitive and motor functions were also improved after PNS treatment at 40 mg/kg. Importantly, PNS treatment elevated the levels of BDNF and TrkB but decreased the expression of p75NTR both in the cortex and hippocampus of HI rats. The therapeutic efficacy of PNS might be correlated with PNS-activated BDNF/TrkB signalling and inactivation of p75NTR expression, providing a novel potential therapy for alleviating HI injury.

LncRNA TCONS_00041002 improves neurological outcomes in neonatal rats with hypoxic-ischemic encephalopathy by inhibiting apoptosis and promoting neuron survival

It has been reported that Neonatal hypoxic-ischemic encephalopathy (HIE) could induce apoptosis in neonates and result in cognitive and sensory impairments, which are associated with poor developmental outcomes. Despite the improvement in neonatology, there is still no clinically effective treatment for HIE presently. Long non-coding RNAs (lncRNAs) play important roles in cellular homeostasis. Nevertheless, their effects in developing rat brains with HI is little known. Here, we established HIE model in neonate rats and explored the expression and function of lncRNAs in HI, and found the expression of 19 lncRNAs was remarkably changed in the brains of HI rats, compared to the sham group. Among them, three lncRNAs (TCONS_00041002, TCONS_00070547, TCONS_00045572) were enriched in the apoptotic process via gene ontology (GO) and pathway analysis, which were selected for the further qRT-PCR verification. Through lentivirus-mediated overexpression of these three lncRNAs, we found that overexpression of TCONS_00041002 attenuated the cell apoptosis, and increased the vitality of neurons after oxygen-glucose deprivation (OGD), therefore reduced the brain infarction and further promoted the neuron survival as well as improved the neurological disorders in the rats subjected to HIE. What's more, ceRNA network prediction and co-expression verification showed that the expression of TCONS_00041002 was positively associated with Foxe1, Pawr and Nfkbiz. Altogether, this study has exhibited that lncRNA TCONS_00041002 participates in the cell apoptosis and neuronal survival of HIE and represents a potential new target for the treatment of HIE.