Neurturin, a member of the glial cell line-derived neurotrophic factor family, affects the development of acetylcholinesterase-positive cells in a three-dimensional model system of retinogenesis

Identification and Validation of Prognostic Markers for Lung Squamous Cell Carcinoma Associated with Chronic Obstructive Pulmonary Disease

Background

Globally, the incidence and associated mortality of chronic obstructive pulmonary disease (COPD) and lung carcinoma are showing a worsening trend. There is increasing evidence that COPD is an independent risk factor for the occurrence and progression of lung carcinoma. This study aimed to identify and validate the gene signatures associated with COPD, which may serve as potential new biomarkers for the prediction of prognosis in patients with lung carcinoma.

Methods

A total of 111 COPD patient samples and 40 control samples were obtained from the GSE76925 cohort, and a total of 4933 genes were included in the study. The weighted gene coexpression network analysis (WGCNA) was performed to identify the modular genes that were significantly associated with COPD. The KEGG pathway and GO functional enrichment analyses were also performed. The RNAseq and clinicopathological data of 490 lung squamous cell carcinoma patients were obtained from the TCGA database. Further, univariate Cox regression and Lasso analyses were performed to screen for marker genes and construct a survival analysis model. Finally, the Human Protein Atlas (HPA) database was used to assess the gene expression in normal and tumor tissues of the lungs.

Results

A 6-gene signature (DVL1, MRPL4, NRTN, NSUN3, RPH3A, and SNX32) was identified based on the Cox proportional risk analysis to construct the prognostic RiskScore survival model associated with COPD. Kaplan–Meier survival analysis indicated that the model could significantly differentiate between the prognoses of patients with lung carcinoma, wherein higher RiskScore samples were associated with a worse prognosis. Additionally, the model had a good predictive performance and reliability, as indicated by a high AUC, and these were validated in both internal and external sets. The 6-gene signature had a good predictive ability across clinical signs and could be considered an independent factor of prognostic risk. Finally, the protein expressions of the six genes were analyzed based on the HPA database. The expressions of DVL1, MRPL4, and NSUN3 were relatively higher, while that of RPH3A was relatively lower in the tumor tissues. The expression of SNX32 was high in both the tumor and paracarcinoma tissues. Results of the analyses using TCGA and GSE31446 databases were consistent with the expressions reported in the HPA database.

Conclusion

Novel COPD-associated gene markers for lung carcinoma were identified and validated in this study. The genes may be considered potential biomarkers to evaluate the prognostic risk of patients with lung carcinoma. Furthermore, some of these genes may have implications as new therapeutic targets and can be used to guide clinical applications.

Optimizing Soluble Cues for Salivary Gland Tissue Mimetics Using a Design of Experiments (DoE) Approach

The development of therapies to prevent or treat salivary gland dysfunction has been limited by a lack of functional in vitro models. Specifically, critical markers of salivary gland secretory phenotype downregulate rapidly ex vivo. Here, we utilize a salivary gland tissue chip model to conduct a design of experiments (DoE) approach to test combinations of seven soluble cues that were previously shown to maintain or improve salivary gland cell function. This approach uses statistical techniques to improve efficiency and accuracy of combinations of factors. The DoE-designed culture conditions improve markers of salivary gland function. Data show that the EGFR inhibitor, EKI-785, maintains relative mRNA expression of Mist1, a key acinar cell transcription factor, while FGF10 and neurturin promote mRNA expression of Aqp5 and Tmem16a, channel proteins involved in secretion. Mist1 mRNA expression correlates with increased secretory function, including calcium signaling and mucin (PAS-AB) staining. Overall, this study demonstrates that media conditions can be efficiently optimized to support secretory function in vitro using a DoE approach.

GD3 synthase deletion alters retinal structure and impairs visual function in mice

Gangliosides are glycosphingolipids abundantly expressed in the vertebrate nervous system, and are classified into a-, b-, or c-series according to the number of sialic acid residues. The enzyme GD3 synthase converts GM3 (an a-series ganglioside) into GD3, a b-series ganglioside highly expressed in the developing and adult retina. The present study evaluated the visual system of GD3 synthase knockout mice (GD3s^-/- ), morphologically and functionally. The absence of b- series gangliosides in the retinas of knockout animals was confirmed by mass spectrometry imaging, which also indicated an accumulation of a-series gangliosides, such as GM3. Retinal ganglion cell (RGC) density was significantly reduced in GD3s^-/- mice, with a similar reduction in the number of axons in the optic nerve. Knockout animals also showed a 15% reduction in the number of photoreceptor nuclei, but no difference in the bipolar cells. The area occupied by GFAP-positive glial cells was smaller in GD3s^-/- retinas, but the number of microglial cells/macrophages did not change. In addition to the morphological alterations, a 30% reduction in light responsiveness was detected through quantification of pS6-expressing RGC, an indicator of neural activity. Furthermore, electroretinography (ERG) indicated a significant reduction in RGC and photoreceptor electrical activity in GD3s^-/- mice, as indicated by scotopic ERG and pattern ERG (PERG) amplitudes. Finally, evaluation of the optomotor response demonstrated that GD3s^-/- mice have reduced visual acuity and contrast sensitivity. These results suggest that b-series gangliosides play a critical role in regulating the structure and function of the mouse visual system.

Regulatory role of NGFs in neurocognitive functions

Nerve growth factors (NGFs), especially the prototype NGF and brain-derived neurotrophic factor (BDNF), have a diverse array of functions in the central nervous system through their peculiar set of receptors and intricate signaling. They are implicated not only in the development of the nervous system but also in regulation of neurocognitive functions like learning, memory, synaptic transmission, and plasticity. Evidence even suggests their role in continued neurogenesis and experience-dependent neural network remodeling in adult brain. They have also been associated extensively with brain disorders characterized by neurocognitive dysfunction. In the present article, we aimed to make an exhaustive review of literature to get a comprehensive view on the role of NGFs in neurocognitive functions in health and disease. Starting with historical perspective, distribution in adult brain, implied molecular mechanisms, and developmental basis, this article further provides a detailed account of NGFs’ role in specified neurocognitive functions. Furthermore, it discusses plausible NGF-based homeostatic and adaptation mechanisms operating in the pathogenesis of neurocognitive disorders and has presents a survey of such disorders. Finally, it elaborates on current evidence and future possibilities in therapeutic applications of NGFs with an emphasis on recent research updates in drug delivery mechanisms. Conclusive remarks of the article make a strong case for plausible role of NGFs in comprehensive regulation of the neurocognitive functions and pathogenesis of related disorders and advocate that future research should be directed to explore use of NGF-based mechanisms in the prevention of implicated diseases as well as to target these molecules pharmacologically.

Green tea (-)epigallocatechin-3-gallate reverses oxidative stress and reduces acetylcholinesterase activity in a streptozotocin-induced model of dementia

Alzheimer's disease (AD) is the most prevalent form of dementia. Intracerebroventricular (ICV) infusion of streptozotocin (STZ) provides a relevant animal model of chronic brain dysfunction that is characterized by long-term and progressive deficits in learning, memory, and cognitive behavior, along with a permanent and ongoing cerebral energy deficit. Numerous studies on green tea epigallocatechin gallate (EGCG) demonstrate its beneficial effects on cognition and memory. As such, this study evaluated, for the first time, the effects of sub-chronic EGCG treatment in rats that were submitted to ICV infusion of STZ (3mg/kg). Male Wistar rats were divided into sham, STZ, sham+EGCG and STZ+EGCG groups. EGCG was administered at a dose of 10mg/kg/day for 4 weeks per gavage. Learning and memory was evaluated using Morris' Water Maze. Oxidative stress markers and involvement of the nitric oxide (NO) system, acetylcholinesterase activity (AChE) and glucose uptake were evaluated as well as glial parameters including S100B content and secretion and GFAP content. Our results show that EGCG was not able to modify glucose uptake and glutathione content, although cognitive deficit, S100B content and secretion, AChE activity, glutathione peroxidase activity, NO metabolites, and reactive oxygen species content were completely reversed by EGCG administration, confirming the neuroprotective potential of this compound. These findings contribute to the understanding of diseases accompanied by cognitive deficits and the STZ-model of dementia.