Synergistic amelioration between Ligusticum striatum DC and borneol against cerebral ischemia by promoting astrocytes-mediated neurogenesis.

ETHNOPHARMACOLOGICAL RELEVANCE: Ligusticum chuanxiong Hort (LCH), with the accepted name of Ligusticum striatum DC in "The Plant List" database, is a widely used ethnomedicine in treating ischemic stroke, and borneol (BO) is usually prescribed with LCH for better therapy. Our previous study confirmed their synergistic effect on neurogenesis against cerebral ischemia. However, the underlying mechanism is still unclear. AIM OF THE STUDY: More and more evidence indicated that astrocytes (ACs) might be involved in the modulation of neurogenesis via polarization reaction. The study was designed to explore the synergic mechanism between LCH and BO in promoting astrocyte-mediated neurogenesis. MATERIALS AND METHODS: After primary cultures and identifications of ACs and neural stem cells (NSCs), the oxygen-glucose deprivation (OGD) model and the concentrations of LCH and BO were optimized. After the OGD-injured ACs were treated by LCH, BO, and their combination, the conditioned mediums were used to culture the OGD-injured NSCs. The proliferation, migration, and differentiation of NSCs were assessed, and the secretions of BDNF, CNTF, and VEGF from ACs were measured. Then the expressions of C3 and PTX3 were detected. Moreover, the mice were performed a global cerebral ischemia/reperfusion model and treated with LCH and (or) BO. After the assessments of Nissl staining, the expressions of Nestin, DCX, GFAP, C3, PTX3, p65 and p-p65 were probed. RESULTS: The most appropriate duration of OGD for the injury of both NSCs and ACs was 6 h, and the optimized concentrations of LCH and BO were 1.30 µg/mL and 0.03 µg/mL, respectively. The moderate OGD environment induced NSCs proliferation, migration, astrogenesis, and neurogenesis, increased the secretions of CNTF and VEGF from ACs, and upregulated the expressions of C3 and PTX3. For the ACs, LCH further increased the secretions of BDNF and CNTF, enhanced PTX3 expression, and reduced C3 expression. Additionally, the conditioned medium from LCH-treated ACs further enhanced NSC proliferation, migration, and neurogenesis. The in vivo study showed that LCH markedly enhanced the Nissl score and neurogenesis, and decreased astrogenesis which was accompanied by downregulations of C3, p-p65, and p-p65/p65 and upregulation of PTX3. BO not only decreased the expression of C3 in ACs both in vitro and in vivo but also downregulated p-p65 and p-p65/p65 in vivo. Additionally, BO promoted the therapeutic effect of LCH for most indices. CONCLUSION: A certain degree of OGD might induce ACs to stimulate the proliferation, astrogenesis, and neurogenesis of NSCs. LCH and BO exhibited a marked synergy in promoting ACs-mediated neurogenesis and reducing astrogenesis, in which LCH played a dominant role and BO boosted the effect of LCH. The mechanism of LCH might be involved in switching the polarization of ACs from A1 to A2, while BO preferred to inhibit the formation of A1 phenotype via downregulating NF-κB pathway.

Ciliary neurotrophic factor reverses aberrant mitochondrial bioenergetics through the JAK/STAT pathway in cultured sensory neurons derived from streptozotocin-induced diabetic rodents.

Mitochondrial dysfunction occurs in sensory neurons and contributes to diabetic neuropathy. Ciliary neurotrophic factor (CNTF) stimulates axon regeneration in type 1 diabetic rodents and prevents deficits in axonal caliber, nerve conduction, and thermal sensation. We tested the hypothesis that CNTF enhances sensory neuron function in diabetes through JAK/STAT (Janus kinase/signal transducers and activators of transcription) signaling to normalize impaired mitochondrial bioenergetics. The effect of CNTF on gene expression and neurite outgrowth of cultured adult dorsal root ganglia (DRG) sensory neurons derived from control and streptozotocin (STZ)-induced diabetic rodents was quantified. Polarization status and bioenergetics profile of mitochondria from cultured sensory neurons were determined. CNTF treatment prevented reduced STAT3 phosphorylation (Tyr 705) in DRG of STZ-diabetic mice and also enhanced STAT3 phosphorylation in rat DRG cultures. CNTF normalized polarization status of the mitochondrial inner membrane and corrected the aberrant oligomycin-induced mitochondrial hyperpolarization in axons of diabetic neurons. The mitochondrial bioenergetics profile demonstrated that spare respiratory capacity and respiratory control ratio were significantly depressed in sensory neurons cultured from STZ-diabetic rats and were corrected by acute CNTF treatment. The positive effects of CNTF on neuronal mitochondrial function were significantly inhibited by the specific JAK inhibitor, AG490. Neurite outgrowth of sensory neurons from age-matched control and STZ-induced diabetic rats was elevated by CNTF and blocked by AG490. We propose that CNTF's ability to enhance axon regeneration and protect from fiber degeneration in diabetes is associated with its targeting of mitochondrial function and improvement of cellular bioenergetics, in part, through JAK/STAT signaling.

Ciliary neurotrophic factor activates NF-κB to enhance mitochondrial bioenergetics and prevent neuropathy in sensory neurons of streptozotocin-induced diabetic rodents.

Diabetes causes mitochondrial dysfunction in sensory neurons that may contribute to peripheral neuropathy. Ciliary neurotrophic factor (CNTF) promotes sensory neuron survival and axon regeneration and prevents axonal dwindling, nerve conduction deficits and thermal hypoalgesia in diabetic rats. In this study, we tested the hypothesis that CNTF protects sensory neuron function during diabetes through normalization of impaired mitochondrial bioenergetics. In addition, we investigated whether the NF-κB signal transduction pathway was mobilized by CNTF. Neurite outgrowth of sensory neurons derived from streptozotocin (STZ)-induced diabetic rats was reduced compared to neurons from control rats and exposure to CNTF for 24 h enhanced neurite outgrowth. CNTF also activated NF-κB, as assessed by Western blotting for the NF-κB p50 subunit and reporter assays for NF-κB promoter activity. Conversely, blockade of NF-κB signaling using SN50 peptide inhibited CNTF-mediated neurite outgrowth. Studies in mice with STZ-induced diabetes demonstrated that systemic therapy with CNTF prevented functional indices of peripheral neuropathy along with deficiencies in dorsal root ganglion (DRG) NF-κB p50 expression and DNA binding activity. DRG neurons derived from STZ-diabetic mice also exhibited deficiencies in maximal oxygen consumption rate and associated spare respiratory capacity that were corrected by exposure to CNTF for 24 h in an NF-κB-dependent manner. We propose that the ability of CNTF to enhance axon regeneration and protect peripheral nerve from structural and functional indices of diabetic peripheral neuropathy is associated with targeting of mitochondrial function, in part via NF-κB activation, and improvement of cellular bioenergetics.

Pharmacotherapy for obese adolescents.

The pharmaceutical search to induce weight loss was precipitated by the United States Food and Drug Administration's (FDA) 1959 formal approval of phentermine for short-term weight loss despite limited research supporting its assertions of weight loss. In addition to sympathomimetic amine products like phentermine, other medications considered in this article include herbal products, sibutramine, orlistat, metformin, and rimonabant. The use of pharmacotherapy for morbidly obese adolescents should be part of a comprehensive weight-loss program that recommends diet, exercise, and behavioral modification. Side effects and the possibility of major adverse effects should be remembered when considering use of these products.