Identification of NURR1 (Exon 4) and FOXA1 (Exon 3) Haplotypes Associated with mRNA Expression Levels in Peripheral Blood Lymphocytes of Parkinson's Patients in Small Indian Population

Genetic analysis of transcription factors in dopaminergic neuronal development in Parkinson's disease

BACKGROUND

Genetic variants of dopaminergic transcription factor-encoding genes are suggested to be Parkinson's disease (PD) risk factors; however, no comprehensive analyses of these genes in patients with PD have been undertaken. Therefore, we aimed to genetically analyze 16 dopaminergic transcription factor genes in Chinese patients with PD.

METHODS

Whole-exome sequencing (WES) was performed using a Chinese cohort comprising 1917 unrelated patients with familial or sporadic early-onset PD and 1652 controls. Additionally, whole-genome sequencing (WGS) was performed using another Chinese cohort comprising 1962 unrelated patients with sporadic late-onset PD and 1279 controls.

RESULTS

We detected 308 rare and 208 rare protein-altering variants in the WES and WGS cohorts, respectively. Gene-based association analyses of rare variants suggested that MSX1 is enriched in sporadic late-onset PD. However, the significance did not pass the Bonferroni correction. Meanwhile, 72 and 1730 common variants were found in the WES and WGS cohorts, respectively. Unfortunately, single-variant logistic association analyses did not identify significant associations between common variants and PD.

CONCLUSIONS

Variants of 16 typical dopaminergic transcription factors might not be major genetic risk factors for PD in Chinese patients. However, we highlight the complexity of PD and the need for extensive research elucidating its etiology.

Integrative analysis reveals structural basis for transcription activation of Nurr1 and Nurr1-RXRα heterodimer

Orphan nuclear receptor Nurr1 plays important roles in the progression of various diseases, including Parkinson's disease, neuroinflammation, Alzheimer's disease, and multiple sclerosis. It can recognize DNA as a monomer or heterodimer with retinoid X receptor α (RXRα). But the molecular mechanism of its transcriptional activity regulation is still largely unknown. Here we obtained a crystal structure of monomer Nurr1 (DNA- and ligand-binding domains, DBD and LBD) bound to NGFI-B response element. The structure exhibited two different forms with distinct DBD orientations, unveiling the conformational flexibility of nuclear receptor monomer. We then generated an integrative model of Nurr1-RXRα heterodimer. In the context of heterodimer, the structural flexibility of Nurr1 would contribute to its transcriptional activity modulation. We demonstrated that the DNA sequence may specifically modulate the transcriptional activity of Nurr1 in the absence of RXRα agonist, but the modulation can be superseded when the agonist binds to RXRα. Together, we propose a set of signaling pathways for the constitutive transcriptional activation of Nurr1 and provide molecular mechanisms for therapeutic discovery targeting Nurr1 and Nurr1-RXRα heterodimer.

Sestrin2 suppresses ferroptosis to alleviate septic intestinal inflammation and barrier dysfunction

OBJECTIVE

Alterations in intestinal function play a crucial role in the pathogenesis of sepsis, and the repair of the intestinal barrier is a potential strategy for the treatment of sepsis. Sestrin2 (SESN2), a highly conserved stress-responsive protein, can be induced in response to stress.

AIM

This paper aimed to explore the role and mechanism of SESN2 in septic intestinal dysfunction. Methods: Blood samples were collected from patients with septic intestinal dysfunction, and Caco-2 cells were subjected to lipopolysaccharide (LPS) to construct in vitro models. The expression level of SESN2 was determined in the blood samples and cells. The impacts of SESN2 overexpression on cell inflammation, oxidative stress, barrier integrity, and MAPK/Nrf2 signaling were evaluated. To determine the mediated role of MAPK signaling and ferroptosis, AMPK inhibitor (Compound C) and ferroptosis inducer (erastin) were separately used to treat cells, and the influences on the above aspects in cells were assessed.

RESULTS

The expression level of SESN2 was down-regulated in patients with septic intestinal dysfunction and LPS-induced cells. SESN2 overexpression was found to suppress cell inflammation and oxidative stress, maintain barrier integrity and activate AMPK/Nrf2 signaling. Following the AMPK signaling was inhibited or the ferroptosis was triggered, the effects of SESN2 overexpression on the cells were both reversed.

CONCLUSION

Reduced SESN2 contributed to inflammatory response and barrier dysfunction in septic intestinal dysfunction by promoting ferroptosis via activating the AMPK/Nrf2 signaling pathway.

FOXA1 transcription activates TFF1 to reduce 6‑OHDA‑induced dopaminergic neuron damage

Forkhead box A1 (FOXA1) plays an important role in the central nervous system, and its loss can lead to the downregulation of tyrosine hydroxylase, which directly affects the synthesis of dopamine, thus leading to Parkinson's disease (PD). The present study aimed to explore the specific role of FOXA1 in PD. Blood samples from patients with PD were collected to determine the expression levels of FOXA1 using reverse transcription-quantitative PCR (RT-qPCR). In addition, mouse dopaminergic neuron MES23.5 cells were induced with 6-hydroxydopamine (6-OHDA) to construct an in vitro PD model in order to study the effect of FOXA1 overexpression on cell inflammation, oxidative stress and apoptosis with RT-qPCR, assay kits and TUNEL assays, respectively. Subsequently, the expression of FOXA1 was silenced to assess the effect on the downstream mechanism. The results revealed that the expression level of FOXA1 was downregulated in patients with PD, and FOXA1 overexpression attenuated 6-OHDA-induced inflammation, oxidative stress and apoptosis in MES23.5 cells. Furthermore, FOXA1 could bind to the trefoil factor 1 (TFF1) promoter, and the effects of FOXA1 overexpression on cells were reversed by TFF1 silencing, indicating that TFF1 mediated the mechanism of FOXA1 overexpression in MES23.5 cells. In conclusion, following FOXA1 transcription, TFF1 expression was activated, thereby relieving 6-OHDA-induced cell inflammation, oxidative stress and apoptosis. The present findings suggested that FOXA1 may serve as a target for the treatment of PD.

Parkinson's Disease Master Regulators on Substantia Nigra and Frontal Cortex and Their Use for Drug Repositioning

Parkinson's disease (PD) is among the most prevalent neurodegenerative diseases. Available evidences support the view of PD as a complex disease, being the outcome of interactions between genetic and environmental factors. In face of diagnosis and therapy challenges, and the elusive PD etiology, the use of alternative methodological approaches for the elucidation of the disease pathophysiological mechanisms and proposal of novel potential therapeutic interventions has become increasingly necessary. In the present study, we first reconstructed the transcriptional regulatory networks (TN), centered on transcription factors (TF), of two brain regions affected in PD, the substantia nigra pars compacta (SNc) and the frontal cortex (FCtx). Then, we used case-control studies data from these regions to identify TFs working as master regulators (MR) of the disease, based on region-specific TNs. Twenty-nine regulatory units enriched with differentially expressed genes were identified for the SNc, and twenty for the FCtx, all of which were considered MR candidates for PD. Three consensus MR candidates were found for SNc and FCtx, namely ATF2, SLC30A9, and ZFP69B. In order to search for novel potential therapeutic interventions, we used these consensus MR candidate signatures as input to the Connectivity Map (CMap), a computational drug repositioning webtool. This analysis resulted in the identification of four drugs that reverse the expression pattern of all three MR consensus simultaneously, benperidol, harmaline, tubocurarine chloride, and vorinostat, thus suggested as novel potential PD therapeutic interventions.

Molecular Insights into NR4A2(Nurr1): an Emerging Target for Neuroprotective Therapy Against Neuroinflammation and Neuronal Cell Death

NR4A2 is a nuclear receptor and a transcription factor, with distinctive physiological features. In the cell nuclei of the central nervous system, it is widely expressed and identified as a crucial regulator of dopaminergic (DA) neuronal differentiation, survival, and maintenance. Importantly, it has regulated different genes crucial for dopaminergic signals, and its expression has been diminished in both aged and PD post-mortem brains and reduced in PD patients. In microglia and astrocytes, the expression of NR4A2 has been found where it can be capable of inhibiting the expression of proinflammatory mediators; hence, it protected inflammation-mediated DA neuronal death. In addition, NR4A2 plays neuroprotective role via regulating different signals. However, NR4A2 has been mainly focused on Parkinson's research, but, in recent times, it has been studied in Alzheimer's disease (AD), multiple sclerosis (MS), and stroke. Altered expression of NR4A2 is connected to AD progression, and activation of its may improve cognitive function. It is downregulated in peripheral blood mononuclear cells of MS patients; nonetheless, its role in MS has not been fully clear. miR-145-5p known as a putative regulator of NR4A2 and in a middle cerebral artery occlusion/reperfusion model, anti-miR-145-5p administration promoted neurological outcomes in rat. To date, various activators and modulators of NR4A2 have been discovered and investigated as probable therapeutic drugs in neuroinflammatory and neuronal cell death models. The NR4A2 gene and cell-based therapy are described as promising drug candidates for neurodegenerative diseases. Moreover, microRNA might have a crucial role in neurodegeneration via affecting NR4A2 expression. Herein, we present the role of NR4A2 in neuroinflammation and neuronal cell death focusing on neurodegenerative conditions and display NR4A2 as a promising therapeutic target for the therapy of neuroprotection.

miRNAome expression profiles in the gonads of adult Melopsittacus undulatus

The budgerigar (Melopsittacus undulatus) is one of the most widely studied parrot species, serving as an excellent animal model for behavior and neuroscience research. Until recently, it was unknown how sexual differences in the behavior, physiology, and development of organisms are regulated by differential gene expression. MicroRNAs (miRNAs) are endogenous short non-coding RNA molecules that can post-transcriptionally regulate gene expression and play a critical role in gonadal differentiation as well as early development of animals. However, very little is known about the role gonadal miRNAs play in the early development of birds. Research on the sex-biased expression of miRNAs in avian gonads are limited, and little is known about M. undulatus. In the current study, we sequenced two small non-coding RNA libraries made from the gonads of adult male and female budgerigars using Illumina paired-end sequencing technology. We obtained 254 known and 141 novel miRNAs, and randomly validated five miRNAs. Of these, three miRNAs were differentially expressed miRNAs and 18 miRNAs involved in sexual differentiation as determined by functional analysis with GO annotation and KEGG pathway analysis. In conclusion, this work is the first report of sex-biased miRNAs expression in the budgerigar, and provides additional sequences to the avian miRNAome database which will foster further functional genomic research.

Single nucleotide polymorphisms and haplotypes of carbonic anhydrase 9 can predict invasive squamous cell carcinoma of uterine cervix

This study aimed to explore the involvement of carbonic anhydrase 9 (CA9) single nucleotide polymorphisms (SNPs) in the development of invasive cancer of uterine cervix for Taiwanese women. Ninety-seven patients with cervical invasive squamous cell carcinoma and 88 with preinvasive squamous cell lesions as well as 324 control women were recruited. Two CA9 SNPs in exons, including rs2071676 (+201, G/A) in exon 1 and rs3829078 (+1081, A/G) in exon 7, rs1048638 (+1584, C/A) in 3'-untranslated region of exon 11, as well as an 18-base pair deletion/insertion (376deltion393) in exon 1 were selected and their genotypic distributions were determined by real-time polymerase chain reaction. Haplotype was then constructed with rs2071676, 376del393, rs3829078 and rs1048638 in order. The results revealed that Taiwanese women with genotypes CA or CA/AA in CA9 SNP rs1048638 displayed a more risk in developing cervical invasive cancer, assigning wild genotype CC as a reference. AA in SNP rs2071676 tended to increase the risk of developing cervical invasive cancer, using GG/GA as a reference. When women had the diplotypes, carrying at least one haplotype A1AA (one mutant allele A in rs2071676, no deletion in 376del393, no mutant allele A in rs3829078 and one mutant allele A in rs1048638), they were significantly susceptible to cervical invasive cancer. In conclusion, CA9 SNP rs1048638 and haplotype A1AA are associated with the susceptibility of cervical invasive squamous cell carcinoma for Taiwanese women.