MiR-142-5p Protects Against 6-OHDA-Induced SH-SY5Y Cell Injury by Downregulating BECN1 and Autophagy

Autophagy-associated non-coding RNAs: Unraveling their impact on Parkinson's disease pathogenesis

BACKGROUND

Parkinson's disease (PD) is a degenerative neurological condition marked by the gradual loss of dopaminergic neurons in the substantia nigra pars compacta. The precise etiology of PD remains unclear, but emerging evidence suggests a significant role for disrupted autophagy-a crucial cellular process for maintaining protein and organelle integrity.

METHODS

This review focuses on the role of non-coding RNAs (ncRNAs) in modulating autophagy in PD. We conducted a comprehensive review of recent studies to explore how ncRNAs influence autophagy and contribute to PD pathophysiology. Special attention was given to the examination of ncRNAs' regulatory impacts in various PD models and patient samples.

RESULTS

Findings reveal that ncRNAs are pivotal in regulating key processes associated with PD progression, including autophagy, α-synuclein aggregation, mitochondrial dysfunction, and neuroinflammation. Dysregulation of specific ncRNAs appears to be closely linked to these pathogenic processes.

CONCLUSION

ncRNAs hold significant therapeutic potential for addressing autophagy-related mechanisms in PD. The review highlights innovative therapeutic strategies targeting autophagy-related ncRNAs and discusses the challenges and prospective directions for developing ncRNA-based therapies in clinical practice. The insights from this study underline the importance of ncRNAs in the molecular landscape of PD and their potential in novel treatment approaches.

The Potential of Targeting Autophagy-Related Non-coding RNAs in the Treatment of Alzheimer's and Parkinson's Diseases

Clearance of accumulated protein aggregates is one of the functions of autophagy. Recently, a clearer understanding of non-coding RNAs (ncRNAs) functions documented that ncRNAs have important roles in several biological processes associated with the development and progression of neurodegenerative disorders. Subtypes of ncRNA, including microRNA (miRNA), long noncoding RNA (lncRNA), and circular RNA (circRNA), are commonly dysregulated in neurodegenerative disorders such as Alzheimer and Parkinson diseases. Dysregulation of these non-coding RNAs has been associated with inhibition or stimulation of autophagy. Decreased miR-124 led to decreased/increased autophagy in experimental model of Alzheimer and Parkinson diseases. Increased BACE1-AS showed enhanced autophagy in Alzheimer disease by targeting miR-214-3p, Beclin-1, LC3-I/LC3-II, p62, and ATG5. A significant increase in NEAT1led to stimulated autophagy in experimental model of PD by targeting PINK1, LC3-I, LC3-II, p62 and miR-374c-5p. In addition, increased BDNF-AS and SNHG1 decreased autophagy in MPTP-induced PD by targeting miR-125b-5p and miR-221/222, respectively. The upregulation of circNF1-419 and circSAMD4A resulted in an increased autophagy by regulating Dynamin-1 and miR-29c 3p, respectively. A detailed discussion of miRNAs, circRNAs, and lncRNAs in relation to their autophagy-related signaling pathways is presented in this study.

Parkinson's Disease as a Risk Factor for Prostate Adenocarcinoma: A Molecular Point of View

INTRODUCTION

Cancer and neurodegeneration are two major leading causes of morbidity and death worldwide. Neurodegeneration results in excessive neuronal cell death, and cancer emerges from increased proliferation and resistance to cell death. Although most epidemiological studies support an inverse association between the risk for the development of neurodegenerative diseases and cancer, increasing evidence points to a positive correlation between specific types of cancer, like prostate adenocarcinoma (PRAD), and neurodegenerative diseases, like Parkinson's disease (PD).

METHODS

PD and PRAD differential genes were screened through the GEO database, and the differential genes were analyzed using David, String, GEPIA, Kaplan-Meier plotter, TIMER2.0, proteinatlas, cBioPortal, and CTD databases to elucidate the biological function and molecular mechanism of PD and PRAD-related genes.

RESULTS

Studies have shown that the hub gene and differentially expressed genes (DEGs) in PD were differentially expressed in PRAD, including CDC20, HSPA4L, ROBO1, DMKN, IFI27L2, LUZP2, PTN, PTGDS. In PRAD, the high expression of HSPA4L, ROBO1, DMKN, IFI27L2, PTN, and PTGDS genes was associated with longer survival, while the patients with low expression of CDC20 and LUZP2 genes had longer survival. The mRNA of CDC20 and LUZP2 were highly expressed, while the mRNAs of HSPA4L, ROBO1, DMKN, IFI27L2, and PTGDS were low expressed. Gene methylation did not affect the survival of patients. The high expression of miR-142, miR-186, miR-30a, miR-497, miR-590, miR-28, and miR-576 in microRNA (miRNA) might potentially be used as biomarkers for the progression of PD and PRAD and for the early diagnosis of PD and PRAD in the populations. The genes in this study were highly associated with B cells, CD8+ T cells, CD4+ T cells, macrophages, neutrophils, and dendritic cells. Somatic mutation mainly focused on missense mutation. Therapeutic drugs included acetaminophen and valproic acid (VPA).

CONCLUSION

Bioinformatics was used to identify potential targets and novel molecular mechanisms that may serve as clinical markers for the diagnosis and treatment of PD and PRAD.

Crosstalk between autophagy and the Keap1-Nrf2-ARE pathway regulates realgar-induced neurotoxicity

ETHNOPHARMACOLOGICAL RELEVANCE

Realgar, the main component of which is As₂S₂ or As₄S₄ (≥90%), is a traditional Chinese natural medicine that has been used to treat carbuncles, furuncles, snake and insect bites, abdominal pain caused by parasitic worms, and epilepsy in China for many years. Because realgar contains arsenic, chronic or excessive use of single-flavor realgar and realgar-containing Chinese patent medicine can lead to drug-induced arsenic poisoning, but the exact mechanism underlying its toxicity to the central nervous system is unclear.

AIM OF THE STUDY

The aim of this study was to clarify the mechanism of realgar-induced neurotoxicity and to investigate the effects of realgar on autophagy and the Keap1-Nrf2-ARE pathway.

MATERIALS AND METHODS

We used rats treated with the autophagy inhibitor 3-methyladenine (3-MA) or adeno-associated virus (AAV2/9-r-shRNA-Sqstm1, sh-p62) to investigate realgar-induced neurotoxicity and explore the specific relationship between autophagy and the Keap1-Nrf2-ARE pathway (the Nrf2 pathway) in the cerebral cortex. Molecular docking analysis was used to assess the interactions among the Nrf2, p62 and Keap1 proteins.

RESULTS

Our results showed that arsenic from realgar accumulated in the brain and blood to cause neuronal and synaptic damage, decrease exploratory behavior and spontaneous movement, and impair memory ability in rats. The mechanism may have involved realgar-mediated autophagy impairment and continuous activation of the Nrf2 pathway via the LC3-p62-Keap1-Nrf2 axis. However, because this activation of the Nrf2 pathway was not sufficient to counteract oxidative damage, apoptosis was aggravated in the cerebral cortex.

CONCLUSIONS

This study revealed that autophagy, the Nrf2 pathway, and apoptosis are involved in realgar-induced central nervous system toxicity and identified p62 as the hub of the LC3-p62-Keap1-Nrf2 axis in the regulation of autophagy, the Nrf2 pathway, and apoptosis.

Role and Dysregulation of miRNA in Patients with Parkinson's Disease

Parkinson's disease (PD) is a neurodegenerative synucleinopathy that has a not yet fully understood molecular pathomechanism behind it. The role of risk genes regulated by small non-coding RNAs, or microRNAs (miRNAs), has also been highlighted in PD, where they may influence disease progression and comorbidities. In this case-control study, we analyzed miRNAs on peripheral blood mononuclear cells by means of RNA-seq in 30 participants, with the aim of identifying miRNAs differentially expressed in PD compared to age-matched healthy controls. Additionally, we investigated the pathways influenced by differentially expressed miRNAs and assessed whether a specific pathway could potentially be associated with PD susceptibility (enrichment analyses performed using the Ingenuity Pathway Analysis tools). Overall, considering that the upregulation of miRNAs might be related with the downregulation of their messenger RNA targets, and vice versa, we found several putative targets of dysregulated miRNAs (i.e., upregulated: hsa-miR-1275, hsa-miR-23a-5p, hsa-miR-432-5p, hsa-miR-4433b-3p, and hsa-miR-4443; downregulated: hsa-miR-142-5p, hsa-miR-143-3p, hsa-miR-374a-3p, hsa-miR-542-3p, and hsa-miR-99a-5p). An inverse connection between cancer and neurodegeneration, called "inverse comorbidity", has also been noted, showing that some genes or miRNAs may be expressed oppositely in neurodegenerative disorders and in some cancers. Therefore, it may be reasonable to consider these miRNAs as potential diagnostic markers and outcome measures.

LncRNA miR-17-92a-1 cluster host gene (MIR17HG) promotes neuronal damage and microglial activation by targeting the microRNA-153-3p/alpha-synuclein axis in Parkinson's disease

Long noncoding RNAs (lncRNAs) have been regarded as modulators of neurodegenerative diseases. Here, we addressed the role of lncRNA miR-17-92a-1 cluster host gene (MIR17HG) in Parkinson's disease (PD). C57BL/6 mice and SH-SY5Y cells were intervened with 6-hydroxydopamine (6-OHDA) to set up PD models in vivo and in vitro. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was implemented to compare the expression of MIR17HG and miR-153-3p. Cell viability and apoptosis were estimated by 3-(4,5-dimethyithiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) and Western blot (WB). The expression of alpha-synuclein (α-syn, SNCA) in BV2 was validated by enzyme-linked immunosorbent assay (ELISA). Reactive oxygen species (ROS) generation and lactate dehydrogenase (LDH) and superoxide dismutase (SOD) activity were evaluated using commercially available kits. Bioinformatics analysis, the dual-luciferase reporter assay, RNA immunoprecipitation (RIP) and qRT-PCR were conducted to demonstrate the interactions between miR-153-3p, MIR17HG, and alpha-synuclein (SNCA). MIR17HG was up-regulated while miR-153-3p was down-regulated in PD patients, mouse models and cells. Inhibiting MIR17HG attenuated neuronal apoptosis, microglial activation and SNCA expression in PD mice. Conditioned medium from 6-OHDA-treated SH-SY5Y cells intensified microglial inflammation, while inhibition of MIR17HG or overexpression of miR-153-3p restrained the inflammatory responses. MIR17HG's function was enforced by sponging miR-153-3p and releasing the attenuation of the putative targets of miR-153-3p and SNCA. Overall, MIR17HG, by targeting miR-153-3p and up-regulating SNCA, stimulates neuronal apoptosis and microglial inflammation in PD.

Berberine Attenuates MPP+-Induced Neuronal Injury by Regulating LINC00943/miR-142-5p/KPNA4/NF-κB Pathway in SK-N-SH Cells

Berberine plays a neuro-protective role in neurodegenerative diseases, including Parkinson's disease (PD). Long non-coding RNAs (lncRNAs) play critical roles in PD pathogenesis. The purpose of this study was to investigate whether LINC00943 was involved in the role of berberine in PD. 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) or 1-methyl-4-phenyl pyridine (MPP⁺) were used to construct PD mouse and cell models, respectively. Cell proliferation was evaluated by Cell Counting Kit-8 (CCK-8) and 5-Ethynyl-2'-deoxyuridine (Edu) assays. Inflammation and cell apoptosis were assessed by enzyme-linked immunosorbent assay (ELISA) and flow cytometry, respectively. Quantitative real-time PCR (qRT-PCR) was employed to test the expression of LINC00943, microRNA (miR)-142-5p, and karyopherin subunit alpha 4 (KPNA4) mRNA. The protein levels of NF-κB pathway-related markers and KPNA4 were measured by western blot. Oxidative stress level was assessed by corresponding kits. The interaction between miR-142-5p and LINC00943 or KPNA4 was determined via dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Berberine inhibited MPP⁺-induced injury in SK-N-SH cells by promoting cell proliferation and suppressing inflammation, apoptosis, and oxidative injury. LINC00943 and KPNA4 were upregulated and miR-142-5p was downregulated in PD mouse and cell models. LINC00943 (or KPNA4) overexpression or miR-142-5p inhibition abated the neuro-protective role of berberine in PD cell model. Moreover, miR-142-5p was a target of LINC00943, and KPNA4 could specially bind to miR-142-5p. Additionally, berberine inhibited NF-κB pathway by regulating LINC00943/miR-142-5p/KPNA4 axis. Berberine protected SK-N-SH cell from MPP⁺-induced neuronal damage via regulating LINC00943/miR-142-5p/KPNA4/NF-κB pathway, highlighting novel evidence for the neuro-protective role of berberine in PD.

Astragaloside IV Protects 6-Hydroxydopamine-Induced SH-SY5Y Cell Model of Parkinson's Disease via Activating the JAK2/STAT3 Pathway

Objectives

Astragaloside IV (AS-IV), the main active component of Astragalus membranaceus, bears anti-inflammatory, antioxidant, and neuroprotective activity. Parkinson’s disease (PD) is a common neurodegenerative disease. This study explored the protective effect of AS-IV on the cell model of PD.

Materials and Methods

SH-SY5Y cells were incubated with different concentrations (10, 50, 100, 150, and 200 μM) of 6-hydroxydopamine (6-OHDA) for 0, 3, 6, 12, 24, and 48 h to establish the PD cell model. Different concentrations (0, 25, 50, 100, 150, and 200 μM) of AS-IV or 15 mM JAK2/STAT3 pathway inhibitor SC99 was added for intervention 2 h before 6-OHDA treatment. The viability and morphological damage of 6-OHDA-treated SH-SY5Y cells were measured using MTT assay and Hoechst 33258 staining. The expression of microtubule associated protein 2 (MAP2) was detected by immunofluorescence staining. The levels of inflammation and oxidative stress were measured using ELISA. Apoptosis of 6-OHDA-treated SH-SY5Y cells was detected using flow cytometry, and phosphorylation level of JAK2 and STAT3 were detected using Western blot analysis.

Results

The survival rate of SH-SY5Y cells treated with 100 μM 6-OHDA for 24 h was about 50%. AS-IV (25–100 μM) significantly improved the viability (all p < 0.01), increased MAP2 expression, and repaired the morphological damage induced by 6-OHDA. AS-IV inhibited IL-1β, IL-6, and TNF-α level (all p < 0.05), reduced MDA and ROS content and increased SOD concentration, thereby reducing inflammation and oxidative stress (all p < 0.01) in 6-OHDA-treated SH-SY5Y cells. Moreover, AS-IV decreased apoptosis rate and Bax/Bcl-2 ratio induced by 6-OHDA (all p < 0.05). Mechanically, AS-IV significantly increased the phosphorylation of JAK2 and STAT3 (p < 0.01); the addition of SC99 decreased the cell viability, increased the apoptosis rate, enhanced the levels of inflammatory factors and oxidative stress.

Conclusion

AS-IV enhanced the cell viability, and inhibited apoptosis, inflammation and oxidative stress of 6-OHDA-treated SH-SY5Y cells via activating the JAK2/STAT3 signaling pathway. This study may confer novel insights for the management of PD.

Insulin and Exendin-4 Reduced Mutated Huntingtin Accumulation in Neuronal Cells

Patients with diabetes mellitus (DM) are more prone to develop cognitive decline and neurodegenerative diseases. A pathological association between an autosomal dominant neurological disorder caused by brain accumulation in mutated huntingtin (mHTT), known as Huntington disease (HD), and DM, has been reported. By using a diabetic mouse model, we previously suggested a central role of the metabolic pathways of HTT, further suggesting the relevance of this protein in the pathology of DM. Furthermore, it has also been reported that intranasal insulin (Ins) administration improved cognitive function in patients with neurodegenerative disorders such as Alzheimer disease, and that exendin-4 (Ex-4) enhanced lifespan and ameliorated glucose homeostasis in a mouse model of HD. Although antioxidant properties have been proposed, the underlying molecular mechanisms are still missing. Therefore, the aim of the present study was to investigate the intracellular pathways leading to neuroprotective effect of Ins and Ex-4 hypoglycemic drugs by using an in vitro model of HD, developed by differentiated dopaminergic neurons treated with the pro-oxidant neurotoxic compound 6-hydroxydopamine (6-ohda). Our results showed that 6-ohda increased mHTT expression and reduced HTT phosphorylation at Ser421, a post-translational modification, which protects against mHTT accumulation. Pre-treatment with Ins or Ex-4 reverted the harmful effect induced by 6-ohda by activating AKT1 and SGK1 kinases, and by reducing the phosphatase PP2B. AKT1 and SGK1 are crucial nodes on the Ins activation pathway and powerful antioxidants, while PP2B dephosphorylates HTT contributing to mHTT neurotoxic effect. In conclusion, present results highlight that Ins and Ex-4 may counteract the neurotoxic effect induced by mHTT, opening novel pharmacological therapeutic strategies against neurodegenerative disorders, with the main focus on HD, still considered an orphan illness.