SIRT5 exacerbates eosinophilic chronic rhinosinusitis by promoting polarization of M2 macrophage.

BACKGROUND: Previous studies implied that local M2 polarization of macrophage promoted mucosal edema and exacerbated TH2 type inflammation in chronic rhinosinusitis with nasal polyps (CRSwNP). However, the specific pathogenic role of M2 macrophages and the intrinsic regulators in the development of CRS remains elusive. OBJECTIVE: We sought to investigate the regulatory role of SIRT5 in the polarization of M2 macrophages and its potential contribution to the development of CRSwNP. METHODS: Real-time reverse transcription-quantitative PCR and Western blot analyses were performed to examine the expression levels of SIRT5 and markers of M2 macrophages in sinonasal mucosa samples obtained from both CRS and control groups. Wild-type and Sirt5-knockout mice were used to establish a nasal polyp model with TH2 inflammation and to investigate the effects of SIRT5 in macrophage on disease development. Furthermore, in vitro experiments were conducted to elucidate the regulatory role of SIRT5 in polarization of M2 macrophages. RESULTS: Clinical investigations showed that SIRT5 was highly expressed and positively correlated with M2 macrophage markers in eosinophilic polyps. The expression of SIRT5 in M2 macrophages was found to contribute to the development of the disease, which was impaired in Sirt5-deficient mice. Mechanistically, SIRT5 was shown to enhance the alternative polarization of macrophages by promoting glutaminolysis. CONCLUSIONS: SIRT5 plays a crucial role in promoting the development of CRSwNP by supporting alternative polarization of macrophages, thus providing a potential target for CRSwNP interventions.

Preparation of graphene quantum dots with glycine as nitrogen source and its interaction with human serum albumin.

Graphene quantum dots (GQDs) could be regarded as graphene with a lateral dimension less than 100 nm. Compared with graphene, GQDs not only possess the excellent properties of graphene but also have been proven to have low toxicity, high fluorescence stability, strong water solubility, as well as better biocompatibility. In this work, an amide bond-based, N-doped graphene quantum dot was synthesized using a simple hydrothermal method. When the reaction time was 4 h and the temperature was 180°C, fluorescence excitation and emission peaks of the product were 340 nm and 450 nm, respectively. Its interaction with human serum albumin (HSA) was investigated using spectroscopy, gel electrophoresis, and molecular simulation. Gel electrophoresis showed that the product did not cause complete scission of the peptide chain in HSA, indicating good biocompatibility. The results of molecular docking showed that the product tended to bind to site III of HSA. This paper provides a meaningful reference for design and development in nanomedicine.

Effect of berberine hydrochloride-functionalized gold nanoparticles on calf thymus DNA: a biophysical study.

Communicated by Ramaswamy H. Sarma.

Stimulation of α(2A)-adrenoceptors promotes the maturation of dendritic spines in cultured neurons of the medial prefrontal cortex.

Dendritic spines are tiny protrusions along dendrites that receive excitatory synaptic inputs and compartmentalize postsynaptic responses in the mature brain. It is known that change in spine morphology is associated with brain functions such as learning and memory. α(2A)-Adrenoceptors (α(2A)-ARs) are highly expressed in cortical neurons and play important roles in neuronal differentiation, growth and neurotrophy. However, little is known about the role of α(2A)-ARs in the maturation of dendritic spines. Here, we report that stimulation of α(2A)-ARs promotes the maturation of dendritic spines in cultured neurons of the medial prefrontal cortex of rodents. Our results show that, stimulation of α(2A)-ARs by guanfacine induced significantly more stubby or mushroom spines in cultured mPFC neurons, with an enlargement of the spine head size. In parallel, the expression of PSD95 (a postsynaptic protein) in guanfacine-treated neurons was enhanced, while that of synapsin (a pre-synaptic protein) kept unchanged. These effects of guanfacine were blocked by co-administered yohimbine, a non-selective α(2)-AR antagonist. The present results implicate a prominent role of α(2A)-ARs in regulating the maturation of dendritic spines in the mPFC.

Administration of thyroid hormone increases reelin and brain-derived neurotrophic factor expression in rat hippocampus in vivo.

Thyroid hormones play important roles in the maturation and function of the central nervous system. However, the underlying mechanism behind thyroid hormone-regulated gene expression in the adult brain is not well understood. Two genes critical for neuronal plasticity and implicated in psychiatric disorders, reelin and brain-derived neurotrophic factor (BDNF), were investigated in the present study. Triiodothyronine (T3), the active form of thyroid hormone was administered to young adult rats in two different manners: systemic injection or local brain infusion. Real time RT-PCR results revealed that T3 administration lead to a significant increase in reelin, total BDNF and exon-specific BDNF mRNA expression in the hippocampus. Furthermore, the association of transcriptional coactivators (including steroid receptor coactivator-1 (SRC-1), cAMP response element binding protein-binding protein (CBP), and thyroid hormone receptor associated protein 220 (TRAP 220)) and RNA polymerase II (RNA Pol II), with reelin and BDNF genes in the rat hippocampus displayed a distinct process following thyroid hormone administration. These findings suggest that association of transcriptional coactivators and RNA Pol II with gene promoters may be a possible mechanism explaining T3-induced reelin and BDNF expression in the hippocampus of young adult rats.

Reciprocal effects of conditioned medium on cultured glioma cells and neural stem cells.

Malignant gliomas are among the most intractable brain cancers. Neural stem cells (NSC) are tissue-specific stem cells with self-renewal capacity and the potential to differentiate into glia and neurons. It has been proposed that NSC could serve as a therapeutic vehicle for the treatment of gliomas. Previous studies showed that NSC, after being implanted into the brain, could migrate to the invading tumor border and target infiltrating tumor cells. These findings suggested that NSC and gliomas could interact, although the mechanism is still not well understood. Here we report that the stem-cell state of NSC is disrupted and NSCs become differentiated when they are co-cultured in vitro with a medium in which glioma cells have been cultured (conditioned medium). The ratio of neurons in these differentiated cells is significantly higher than that in the controls (NSC cultured in regular medium). Conditioned medium in which primary NSC have been grown can inhibit proliferation of glioma cells, an effect that was greater with NSC conditioned medium of embryonic mice than neonatal mice. These results suggest that glioma cells and NSC can interact at the niche or micro-environment level, potentially leading to proliferation and differentiation of NSC and suppression of proliferation of glioma cells. These findings may shed new light on the development of novel strategies for the treatment of malignant gliomas.