Glutamate receptor gene GRIN2A, coffee, and Parkinson disease

Unraveling the Neuroprotective Effect of Tinospora cordifolia in a Parkinsonian Mouse Model through the Proteomics Approach

Stress-induced dopaminergic (DAergic) neuronal death in the midbrain region is the primary cause of Parkinson's disease (PD). Following the discovery of l-dopa, multiple drugs have been developed to improve the lifestyle of PD patients; however, none have been suitable for clinical use due to their multiple side effects. Tinospora cordifolia has been used in traditional medicines to treat neurodegenerative diseases. Previously, we reported the neuroprotective role of Tc via inhibition of NF-κB-associated proinflammatory cytokines against MPTP-intoxicated Parkinsonian mice. In the present study, we investigated the neuroprotective molecular mechanism of Tc in a rotenone (ROT)-intoxicated mouse model, using a proteomics approach. Mice were pretreated with Tc extract by oral administration, followed by ROT intoxication. Behavioral tests were performed to check motor functions of mice. Protein was isolated, and label-free quantification (LFQ) was carried out to identify differentially expressed protein (DEP) in control vs PD and PD vs treatment groups. Results were validated by qRT-PCR with the expression of target genes correlating with the proteomics data. In this study, we report 800 DEPs in control vs PD and 133 in PD vs treatment groups. In silico tools demonstrate significant enrichment of biochemical and molecular pathways with DEPs, which are known to be important for PD progression including mitochondrial gene expression, PD pathways, TGF-β signaling, and Alzheimer's disease. This study provides novel insights into the PD progression as well as new therapeutic targets. More importantly, it demonstrates that Tc can exert therapeutic effects by regulating multiple pathways, resulting in neuroprotection.

The role of GPCRs in bone diseases and dysfunctions

The superfamily of G protein-coupled receptors (GPCRs) contains immense structural and functional diversity and mediates a myriad of biological processes upon activation by various extracellular signals. Critical roles of GPCRs have been established in bone development, remodeling, and disease. Multiple human GPCR mutations impair bone development or metabolism, resulting in osteopathologies. Here we summarize the disease phenotypes and dysfunctions caused by GPCR gene mutations in humans as well as by deletion in animals. To date, 92 receptors (5 glutamate family, 67 rhodopsin family, 5 adhesion, 4 frizzled/taste2 family, 5 secretin family, and 6 other 7TM receptors) have been associated with bone diseases and dysfunctions (36 in humans and 72 in animals). By analyzing data from these 92 GPCRs, we found that mutation or deletion of different individual GPCRs could induce similar bone diseases or dysfunctions, and the same individual GPCR mutation or deletion could induce different bone diseases or dysfunctions in different populations or animal models. Data from human diseases or dysfunctions identified 19 genes whose mutation was associated with human BMD: 9 genes each for human height and osteoporosis; 4 genes each for human osteoarthritis (OA) and fracture risk; and 2 genes each for adolescent idiopathic scoliosis (AIS), periodontitis, osteosarcoma growth, and tooth development. Reports from gene knockout animals found 40 GPCRs whose deficiency reduced bone mass, while deficiency of 22 GPCRs increased bone mass and BMD; deficiency of 8 GPCRs reduced body length, while 5 mice had reduced femur size upon GPCR deletion. Furthermore, deficiency in 6 GPCRs induced osteoporosis; 4 induced osteoarthritis; 3 delayed fracture healing; 3 reduced arthritis severity; and reduced bone strength, increased bone strength, and increased cortical thickness were each observed in 2 GPCR-deficiency models. The ever-expanding number of GPCR mutation-associated diseases warrants accelerated molecular analysis, population studies, and investigation of phenotype correlation with SNPs to elucidate GPCR function in human diseases.

The emerging science of precision medicine and pharmacogenomics for Parkinson's disease

Current therapies for Parkinson's disease are problematic because they are symptomatic and have adverse effects. New drugs have failed in clinical trials because of inadequate efficacy. At the core of the problem is trying to make one drug work for all Parkinson's disease patients, when we know this premise is wrong because (1) Parkinson's disease is not a single disease, and (2) no two individuals have the same biological makeup. Precision medicine is the goal to strive for, but we are only at the beginning stages of building the infrastructure for one of the most complex projects in the history of science, and it will be a long time before Parkinson's disease reaps the benefits. Pharmacogenomics, a cornerstone of precision medicine, has already proven successful for many conditions and could also propel drug discovery and improve treatment for Parkinson's disease. To make progress in the pharmacogenomics of Parkinson's disease, we need to change course from small inconclusive candidate gene studies to large-scale rigorously planned genome-wide studies that capture the nuclear genome and the microbiome. Pharmacogenomic studies must use homogenous subtypes of Parkinson's disease or apply the brute force of statistical power to overcome heterogeneity, which will require large sample sizes achievable only via internet-based methods and electronic databases. Large-scale pharmacogenomic studies, together with biomarker discovery efforts, will yield the knowledge necessary to design clinical trials with precision to alleviate confounding by disease heterogeneity and interindividual variability in drug response, two of the major impediments to successful drug discovery and effective treatment. © 2017 International Parkinson and Movement Disorder Society.

Cutaneous malignant melanoma and Parkinson disease: Common pathways?

The mechanisms underlying the high prevalence of cutaneous malignant melanoma (CMM) in Parkinson disease (PD) are unclear, but plausibly involve common pathways. 129Ser-phosphorylated α-synuclein, a pathological PD hallmark, is abundantly expressed in CMM, but not in normal skin. In inherited PD, PARK genes harbor germline mutations; the same genes are somatically mutated in CMM, or their encoded proteins are involved in melanomagenesis. Conversely, genes associated with CMM affect PD risk. PD/CMM-targeted cells share neural crest origin and melanogenesis capability. Pigmentation gene variants may underlie their susceptibility. We review putative genetic intersections that may be suggestive of shared pathways in neurodegeneration/melanomagenesis. Ann Neurol 2016;80:811-820.

Pseudomonas aeruginosa infection augments inflammation through miR-301b repression of c-Myb-mediated immune activation and infiltration

microRNAs (miRNAs) play critical roles in various biological processes including cell proliferation, development, and host defense. However, the molecular mechanism for miRNAs in regulating bacterial-induced inflammation remains largely unclear. Here we report that miR-301b augments pro-inflammatory response during pulmonary infection and caffeine (CAF) suppresses miR-301b’s effect and thereby augmenting respiratory immunity. LPS treatment or Pseudomonas aeruginosa infection induces miR-301b expression via a TLR4/MyD88/NF-κB pathway. Importantly, CAF decreases miR-301b expression through negative regulation of the cAMP/PKA/NF-κB axis. Further, c-Myb is identified as a target of miR-301b, which positively modulates anti-inflammatory cytokines IL-4 and TGF-β1, but negatively regulates pro-inflammatory cytokines MIP-1α and IL-17A. Moreover, repression of miR-301b results in increased transcription of c-Myb and elevated levels of neutrophil infiltration, thereby alleviating infectiou symptoms in mice. These findings reveal miR-301b as a new controller of inflammatory response by repressing c-Myb function to inhibit anti-inflammatory response to bacterial infection, representing a novel mechanism for balancing inflammation.