Airway basal stem cells are necessary for the maintenance of functional intraepithelial airway macrophages.

Adult stem cells play a crucial role in tissue homeostasis and repair through multiple mechanisms. In addition to being able to replace aged or damaged cells, stem cells provide signals that contribute to the maintenance and function of neighboring cells. In the lung, airway basal stem cells also produce cytokines and chemokines in response to inhaled irritants, allergens, and pathogens, which affect specific immune cell populations and shape the nature of the immune response. However, direct cell-to-cell signaling through contact between airway basal stem cells and immune cells has not been demonstrated. Recently, a unique population of intraepithelial airway macrophages (IAMs) has been identified in the murine trachea. Here, we demonstrate that IAMs require Notch signaling from airway basal stem cells for maintenance of their differentiated state and function. Furthermore, we demonstrate that Notch signaling between airway basal stem cells and IAMs is required for antigen-induced allergic inflammation only in the trachea where the basal stem cells are located whereas allergic responses in distal lung tissues are preserved consistent with a local circuit linking stem cells to proximate immune cells. Finally, we demonstrate that IAM-like cells are present in human conducting airways and that these cells display Notch activation, mirroring their murine counterparts. Since diverse lung stem cells have recently been identified and localized to specific anatomic niches along the proximodistal axis of the respiratory tree, we hypothesize that the direct functional coupling of local stem cell-mediated regeneration and immune responses permits a compartmentalized inflammatory response.

Dried root of Rehmannia glutinosa extracts prevents steroid-induced avascular necrosis of femoral head by activating the wingless-type (Wnt)/ß-catenin signal pathway.

Steroid-induced avascular necrosis of femoral head (SANFH) is one of the most common complications caused by long-term or excessive clinical use of glucocorticoids. This study aimed to investigate the effects of dried root of Rehmannia glutinosa extracts (DRGE) in SANFH. First, SANFH rat model was established by dexamethasone (Dex). Tissue change and proportion of empty lacunae were detected by hematoxylin and eosin staining. Protein levels were detected by western bloting analysis. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) was performed to assess apoptosis of femoral head tissue. Cell viability and apoptosis of MC3T3-E1 cells were assessed by Cell Counting Kit-8 assay and flow cytometry. ALP activity and cell mineralization were detected by ALP staining assay and Alizarin red staining. The findings showed that DRGE improved tissue damage, inhibited apoptosis, and promoted osteogenesis in SANFH rats. In vitro, DRGE increased cell viability, inhibited cell apoptosis, promoted osteoblast differentiation, reduced the levels of p-GSK-3ß/GSK-3ß, but increased the levels of ß-catenin in cells treated with Dex. Furthermore, DKK-1, an inhibitor of the wingless-type (Wnt)/ß-catenin signaling pathway, reversed the effect of DRGE on cell apoptosis and ALP activity in cells treated with Dex. In conclusion, DRGE prevents SANFH by activating the Wnt/ß-catenin signaling pathway, indicating that DRGE may be a hopeful choice drug to prevent and treat patients with SANFH.

Knockdown of lncRNA JPX suppresses IL-1ß-stimulated injury in chondrocytes through modulating an miR-25-3p/PPID axis.

The aim of this study was to investigate the potential mechanisms of long noncoding (lnc) RNA Just proximal to X-inactive specific transcript (JPX) in interleukin (IL)-1ß-stimulated chondrocytes. Human C28/I2 chondrocytes were treated with IL-1ß to simulate osteoarthritic (OA) injury. The expression levels of JPX, microRNA (miRNA/miR)-25-3p, and peptidylprolyl isomerase D (PPID) were measured using reverse transcription-quantitative PCR or western blotting. The IL-1ß-stimulated injury was assessed using a Cell Counting Kit-8 assay, flow cytometry, and western blot analysis. The targeted relationship between miR-25-3p, JPX, and PPID was verified using a dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. The results showed that JPX expression was upregulated in OA patients and IL-1ß-stimulated chondrocytes. JPX knockdown enhanced cell viability and suppressed apoptosis of IL-1ß-stimulated chondrocytes. miR-25-3p inhibition rescued the inhibitory effect of JPX knockdown on IL-1ß-stimulated injury. PPID overexpression eliminated the effects of JPX knockdown on IL-1ß-stimulated chondrocytes. In conclusion, JPX knockdown increased cell viability and reduced apoptosis in IL-1ß-stimulated chondrocytes, and this involved modulation of a miR-25-3p/PPID axis.

Novel pyrrolo[2,1-c][1,4]benzodiazepine-3,11-dione (PBD) derivatives as selective HDAC6 inhibitors to suppress tumor metastasis and invasion in vitro and in vivo.

Selective inhibition of histone deacetylase 6 (HDAC6) has been emerged as a promising approach to cancer treatment. As a pivotal strategy for drug discovery,molecular hybridization was introduced in this study and a series of pyrrolo[2,1-c][1,4] benzodiazepine-3,11-diones (PBDs) based hydroxamic acids was rationally designed and synthesizedas novel selective HDAC6 inhibitors. Preliminary in vitro enzyme inhibition assay and structure-activity relationship (SAR) discussion confirmed our design strategy and met the expectation. Several of the compounds showed high potent against HDAC6 enzyme in vitro, and compound A7 with a long aliphatic linker was revealed to have the similar activity as the positive control tubastatin A. Further in vitro characterization of A7 demonstrates the metastasis inhibitory potency in MDA-MB-231 cell line and western blotting showed that A7 could induce the upregulation of Ac-α-tubulin, but not induce the excessive acetylation of histone H3, which indicated that the compound had HDAC6 targeting effect in MDA-MB-231 cells. In vivo study revealed that compound A7 has satisfactory inhibitory effects onliver and lung metastasis of breast cancer in mice. Molecular docking released that A7 could fit well with the receptor and interact with some key residues, which lays a foundation for further structural modifications to elucidate the interaction mode between compounds and target protein. This pharmacological investigation workflow provided a reasonable and reference methodto examine the pharmacological effects of inhibiting HDAC6 with a single molecule, either in vitro or in vivo. All of these results suggested that A7 is a promising lead compound that could lead to the further development of novel selective HDAC6 inhibitors for the treatment of tumor metastasis.

Mitochondrial Effects of PGC-1alpha Silencing in MPP+ Treated Human SH-SY5Y Neuroblastoma Cells.

The dopaminergic neuron degeneration and loss that occurs in Parkinson's disease (PD) has been tightly linked to mitochondrial dysfunction. Although the aged-related cause of the mitochondrial defect observed in PD patients remains unclear, nuclear genes are of potential importance to mitochondrial function. Human peroxisome proliferator-activated receptor γ coactivator-1alpha (PGC-1α) is a multi-functional transcription factor that tightly regulates mitochondrial biogenesis and oxidative capacity. The goal of the present study was to explore the potential pathogenic effects of interference by the PGC-1α gene on N-methyl-4-phenylpyridinium ion (MPP+)-induced SH-SY5Y cells. We utilized RNA interference (RNAi) technology to probe the pathogenic consequences of inhibiting PGC-1α in the SH-SY5Y cell line. Remarkably, a reduction in PGC-1α resulted in the reduction of mitochondrial membrane potential, intracellular ATP content and intracellular H2O2 generation, leading to the translocation of cytochrome c (cyt c) to the cytoplasm in the MPP+-induced PD cell model. The expression of related proteins in the signaling pathway (e.g., estrogen-related receptor α (ERRα), nuclear respiratory factor 1 (NRF-1), NRF-2 and Peroxisome proliferator-activated receptor γ (PPARγ)) also decreased. Our finding indicates that small interfering RNA (siRNA) interference targeting the PGC-1α gene could inhibit the function of mitochondria in several capacities and that the PGC-1α gene may modulate mitochondrial function by regulating the expression of ERRα, NRF-1, NRF-2 and PPARγ. Thus, PGC-1α can be considered a potential therapeutic target for PD.

Overexpression of PGC-1α Influences Mitochondrial Signal Transduction of Dopaminergic Neurons.

Parkinson's disease (PD) is a common neurodegenerative disease in the elderly. Mitochondrial dysfunction plays an important role in the pathogenesis of PD. Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) is a powerful transcription factor, interacting with multiple transcription factors and widely involving in the regulation of mitochondrial biogenesis, oxidative stress, and other processes. The present study investigated the neuroprotective effects and signal transduction mechanisms of the overexpression of PGC-1α on N-methyl-4-phenylpyridinium ion (MPP(+))-induced mitochondrial damage in SH-SY5Y cell, establishing the cell model of overexpression of PGC-1α and the cell model of PD by using adenoviral vectors and MPP(+). 3-(4,5-Dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide thiazolyl blue (MTT) assay was used to investigate the effects of MPP(+) and adenovirus on the cell viability of SH-SY5Y cells and the cell viability of experimental groups. Western blot and real-time PCR analysis were used to detect the expression of PGC-1α. Flow cytometry and ELISA were used to detect mitochondrial membrane potential and the level of cytochrome C, respectively. The level of intracellular ATP and H2O2 was measured by multifunctional fluorescence microplate. Western blot analysis and real-time PCR were used to observe the expression of estrogen-related receptor α (ERRα), peroxisome proliferator-activated receptor γ (PPARγ), nuclear respiratory factor (NRF)-1, and NRF-2. Confocal fluorescence analysis was used to observe subcellular localization of PGC-1α in SH-SY5Y cells under the intervention of MPP(+). The expression of PGC-1α messenger RNA and protein significantly increased in Adv-PGC-1α + GFP groups, compared with the control and Adv-GFP groups (P < 0.01). The overexpression of PGC-1α could increase mitochondrial membrane potential, reduce the release of mitochondrial cytochrome C, inhibit H2O2 production, and improve the level of ATP in SH-SY5Y cells. The trend of expression of ERRα, PPARγ, and NRF-1 was more consistent with PGC-1α, the most remarkable change is ERRα, but the expression of NRF-2 has no significant changes. Under the gradually increasing concentration of MPP(+), microscale PGC-1α gradually appeared in the cytoplasm of SH-SY5Y cells. The overexpression of PGC-1α can inhibit MPP(+)-induced mitochondrial damage in SH-SY5Y cells, and PGC-1α may realize the neuroprotective effects via the ERRα, PPARγ, and NRF-1 pathway.

Treatment with hydrogen molecules prevents RANKL-induced osteoclast differentiation associated with inhibition of ROS formation and inactivation of MAPK, AKT and NF-kappa B pathways in murine RAW264.7 cells.

The bone protective effects of the hydrogen molecule (H2) have been demonstrated in several osteoporosis models while the underlying molecular mechanism has remained unclear. Osteoclast differentiation is an important factor related to the pathogenesis of bone-loss related diseases. In this work, we evaluated the effects of incubation with H2 on receptor activator of NFκB ligand (RANKL)-induced osteoclast differentiation. We found that treatment with H2 prevented RANKL-induced osteoclast differentiation in RAW264.7 cells and BMMs. Treatment with H2 inhibits the ability to form resorption pits of BMMs stimulated by RANKL. Treatment with H2 reduced mRNA levels of osteoclast-specific markers including tartrate resistant acid phosphatase, calcitonin receptor, cathepsin K, metalloproteinase-9, carbonic anhydrase typeII, and vacuolar-type H(+)-ATPase. Treatment with H2 decreased intracellular reactive oxygen species (ROS) formation, suppressed NADPH oxidase activity, down-regulated Rac1 activity and Nox1 expression, reduced mitochondrial ROS formation, and enhanced nuclear factor E2-related factor 2 nuclear translocation and heme oxygenase-1 activity. In addition, treatment with H2 suppressed RANKL-induced expression of nuclear factor of activated T cells c1 and c-Fos. Furthermore, treatment with H2 suppressed NF-κB activation and reduced phosphorylation of p38, extracellular signal-regulated kinase, c-Jun-N-terminal kinase, and protein kinases B (AKT) stimulated with RANKL. In conclusion, hydrogen molecules prevented RANKL-induced osteoclast differentiation associated with inhibition of reactive oxygen species formation and inactivation of NF-κB, mitogen-activated protein kinase and AKT pathways.