Regulation of miR-146a by RelA/NFkB and p53 in STHdhQ111/HdhQ111 Cells, a Cell Model of Huntington's Disease

Huntington's disease (HD) is caused by the expansion of N-terminal polymorphic poly Q stretch of the protein huntingtin (HTT). Deregulated microRNAs and loss of function of transcription factors recruited to mutant HTT aggregates could cause characteristic transcriptional deregulation associated with HD. We observed earlier that expressions of miR-125b, miR-146a and miR-150 are decreased in STHdhQ111/HdhQ111 cells, a model for HD in comparison to those of wild type STHdhQ7/HdhQ7 cells. In the present manuscript, we show by luciferase reporter assays and real time PCR that decreased miR-146a expression in STHdhQ111/HdhQ111 cells is due to decreased expression and activity of p65 subunit of NFkB (RelA/NFkB). By reporter luciferase assay, RT-PCR and western blot analysis, we also show that both miR-150 and miR-125b target p53. This partially explains the up regulation of p53 observed in HD. Elevated p53 interacts with RelA/NFkB, reduces its expression and activity and decreases the expression of miR-146a, while knocking down p53 increases RelA/NFkB and miR-146a expressions. We also demonstrate that expression of p53 is increased and levels of RelA/NFkB, miR-146a, miR-150 and miR-125b are decreased in striatum of R6/2 mice, a mouse model of HD and in cell models of HD. In a cell model, this effect could be reversed by exogenous expression of chaperone like proteins HYPK and Hsp70. We conclude that (i) miR-125b and miR-150 target p53, which in turn regulates RelA/NFkB and miR-146a expressions; (ii) reduced miR-125b and miR-150 expressions, increased p53 level and decreased RelA/NFkB and miR-146a expressions originate from mutant HTT (iii) p53 directly or indirectly regulates the expression of miR-146a. Our observation of interplay between transcription factors and miRNAs using HD cell model provides an important platform upon which further work is to be done to establish if such regulation plays any role in HD pathogenesis

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed

Binding of Thyroid Hormone to Freshwater Perch Leydig Cell Nuclei-rich Preparation and its Functional Relevance

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Inhibition of Amyloid Fibril Growth by Nanoparticle Coated with Histidine-Based Polymer

Amyloid protein fibrillation is responsible for variety of neurological disorders and thus inhibition of fibrillation is a potential therapeutic strategy for these diseases. Recent study shows that nanoparticles can significantly influence the kinetics of amyloid fibrillation, depending on their surface chemistry. Here we demonstrate that amyloid fibril formation can be completely inhibited by nanoparticles coated with histidine-based polymer. We have designed nanoparticles with modular surface chemistry and found that the presence of cationic and anionic surface charge, along with weakly hydrophobic functional groups, is essential in inhibiting the amyloid fibrillation processes. This work shows that the appropriate nanoprobe can be designed for controlling the amyloid fibrillation kinetics and for complete inhibition of fibrillation

Inhibition of Protein Aggregation by Iron Oxide Nanoparticles Conjugated with Glutamine- and Proline-Based Osmolytes

Osmolytes are small organic biomolecules utilized by cells and organisms to counter unfavorable physiological conditions that challenge protein stability and function. Among them, some osmolytes are shown to prevent protein aggregation and act as chemical chaperones. We recently showed that nanoparticle forms of sugar-based osmolytes can enhance their chaperone performance typically by 1000–100 000 times. Here, we show that the nanoparticle form of amino acid-based osmolytes such as glutamine and proline can inhibit protein aggregation 1000–10 000 times better than respective molecular glutamine and proline. Specifically, we designed a glutamine/proline-conjugated nanoparticle with zwitterionic surface charge for best performance in inhibiting lysozyme aggregation in extracellular space and inhibiting mutant huntingtin protein aggregation in intracellular space. This result indicates that an efficient artificial chaperone can be made to inhibit protein aggregation using the nanoparticle form of osmolytes and other antiamyloidogenic molecules

Grb2 is regulated by foxd3 and has roles in preventing accumulation and aggregation of mutant huntingtin.

Growth factor receptor protein binding protein 2 (Grb2) is known to be associated with intracellular growth and proliferation related signaling cascades. Huntingtin (Htt), a ubiquitously expressed protein, when mutated, forms toxic intracellular aggregates - the hallmark of Huntington's disease (HD). We observed an elevated expression of Grb2 in neuronal cells in animal and cell models of HD. Grb2 overexpression was predominantly regulated by the transcription factor Forkhead Box D3 (Foxd3). Exogenous expression of Grb2 also reduced aggregation of mutant Htt in Neuro2A cells. Grb2 is also known to interact with Htt, depending on epidermal growth factor receptor (EGFR) activation. Grb2- mutant Htt interaction in the contrary, took place in vesicular structures, independent of EGFR activation that eventually merged with autophagosomes and activated the autophagy machinery helping in autophagosome and lysosome fusion. Grb2, with its emerging dual role, holds promise for a survival mechanism for HD

Sugar-Terminated Nanoparticle Chaperones Are 10²–10⁵ Times Better Than Molecular Sugars in Inhibiting Protein Aggregation and Reducing Amyloidogenic Cytotoxicity

Sugar-based osmolyte molecules are known to stabilize proteins under stress, but usually they have poor chaperone performance in inhibiting protein aggregation. Here, we show that the nanoparticle form of sugars molecule can enhance their chaperone performance typically by 10²–10⁵ times, compared to molecular sugar. Sugar-based plate-like nanoparticles of 20−40 nm hydrodynamic size have been synthesized by simple heating of acidic aqueous solution of glucose/sucrose/maltose/trehalose. These nanoparticles have excitation-dependent green/yellow/orange emission and surface chemistry identical to the respective sugar molecule. Fibrillation of lysozyme/insulin/amyloid beta in extracellular space, aggregation of mutant huntingtin protein inside model neuronal cell, and cytotoxic effect of fibrils are investigated in the presence of these sugar nanoparticles. We found that sugar nanoparticles are 10²–10⁵ times efficient than respective sugar molecules in inhibiting protein fibrillation and preventing cytotoxicity arising of fibrils. We propose that better performance of the nanoparticle form is linked to its stronger binding with fibril structure and enhanced cell uptake. This result suggests that nanoparticle form of osmolyte can be an attractive option in prevention and curing of protein aggregation-derived diseases

Trehalose-Functionalized Gold Nanoparticle for Inhibiting Intracellular Protein Aggregation

Trehalose is a well-known antiamyloidogenic molecule that inhibits protein aggregation under the intracellular/extracellular condition, and recent work shows that the nanoparticle form of trehalose can further enhance this performance. Here we have designed a trehalose-functionalized Au nanoparticle that can inhibit the aggregation of a polyglutamine-containing mutant protein inside the neuronal cell. Designed nanoparticles have a 20–30 nm Au core with about 350 ± 50 trehalose molecules per particle on the surface on average. They enter the cell, inhibit mutant protein aggregation, and enhance the cell survival against toxic protein aggregates. This work extends the application potential of trehalose for the understanding and treatment of different diseases involving protein aggregation

Efficient Inhibition of Protein Aggregation, Disintegration of Aggregates, and Lowering of Cytotoxicity by Green Tea Polyphenol-Based Self-Assembled Polymer Nanoparticles

Green tea polyphenol epigallocatechin-3-gallate (EGCG) is known for its antiamyloidogenic property, and it is observed that molecular EGCG binds with amyloid structure, redirects fibrillation kinetics, remodels mature fibril, and lowers the amyloid-derived toxicity. However, this unique property of EGCG is difficult to utilize because of their poor chemical stability and substandard bioavailability. Here we report a nanoparticle form of EGCG of 25 nm size (nano-EGCG) which is 10–100 times more efficient than molecular EGCG in inhibiting protein aggregation, disintegrating mature protein aggregates, and lowering amyloidogenic cytotoxicity. The most attractive advantage of nano-EGCG is that it efficiently protects neuronal cells from the toxic effect of extracellular amyloid beta or intracellular mutant huntingtin protein aggregates by preventing their aggregation. We found that the better performance of nano-EGCG is due to the combined effect of increased chemical stability of EGCG against degradation, stronger binding with protein aggregates, and efficient entry into the cell for interaction with aggregated protein structure. This result indicates that the nanoparticle form of antiamyloidogenic molecules can be more powerful in prevention and curing of protein aggregation derived diseases