5-Phenyl valeric acid attenuates α-synuclein aggregation and endoplasmic reticulum stress in rotenone-induced Parkinson's disease rats: A molecular mechanistic study.

The abnormal accumulation of fibrillar α-synuclein in the substantia nigra contributes to Parkinson's disease (PD). Chemical chaperones like 4-phenyl butyric acid (4PBA) show neuroprotective potential, but high doses are required. A derivative, 5-phenyl valeric acid (5PVA), has reported therapeutic potential for PD by reducing Pael-R expression. This study assessed 5PVA's efficacy in PD animals and its molecular mechanism. In vitro studies revealed 5PVA's anti-aggregation ability against alpha-synuclein and neuroprotective effects on SHSY5Y neuroblastoma cells exposed to rotenone. PD-like symptoms were induced in SD rats with rotenone, followed by 5PVA treatment at 100 mg/kg and 130 mg/kg. Behavioral analysis showed significant improvement in memory and motor activity with 5PVA administration. Histopathological studies demonstrated normal neuronal histoarchitecture in mid-brain tissue sections of 5PVA-treated animals compared to the PD group. mRNA studies revealed significant suppression in the expression of various protein folding and heat-shock protein markers in the 5PVA-treated group. In conclusion, 5PVA, with its anti-aggregation ability against alpha-synuclein, acts as a chemical chaperone, showing potential as a therapeutic candidate for PD treatment.

Linalool acts as a chemical chaperone by inhibiting amyloid-ß aggregation.

Linalool is a neuroprotective monoterpene found in essential oils from aromatic plants. Linalool's effectiveness in AD animal models has been established previously, but its mechanisms of action remain unclear. Therefore, this study aims to investigate whether linalool binds directly to the amyloid beta (Aß) fibrils to understand it's role in preventing neurodegeneration. The anti-aggregation ability of Linalool was determined using Dithiothreitol (DTT), and thermal aggregation assays followed by Thioflavin T (ThT) binding assay. AD animals were treated with Linalool, and Thioflavin T staining was used to check the binding of linalool to Aß fibrils in rat brain tissue sections. Preliminary studies revealed the anti-aggregation potential of linalool under the thermal and chemical stimulus. Further, in ThT binding assay Linalool inhibited Aß aggregation, binding directly to Aß fibrils. The reduced fluorescence intensity of ThT in AD brain tissues following linalool administration, highlights its neuroprotective potential as a therapeutic agent for AD.

Endoplasmic reticulum stress and its role in various neurodegenerative diseases.

The Endoplasmic reticulum (ER), a critical cellular organelle, maintains cellular homeostasis by regulating calcium levels and orchestrating essential functions such as protein synthesis, folding, and lipid production. A pivotal aspect of ER function is its role in protein quality control. When misfolded proteins accumulate within the ER due to factors like protein folding chaperone dysfunction, toxicity, oxidative stress, or inflammation, it triggers the Unfolded protein response (UPR). The UPR involves the activation of chaperones like calnexin, calreticulin, glucose-regulating protein 78 (GRP78), and Glucose-regulating protein 94 (GRP94), along with oxidoreductases like protein disulphide isomerases (PDIs). Cells employ the Endoplasmic reticulum-associated degradation (ERAD) mechanism to counteract protein misfolding. ERAD disruption causes the detachment of GRP78 from transmembrane proteins, initiating a cascade involving Inositol-requiring kinase/endoribonuclease 1 (IRE1), Activating transcription factor 6 (ATF6), and Protein kinase RNA-like endoplasmic reticulum kinase (PERK) pathways. The accumulation and deposition of misfolded proteins within the cell are hallmarks of numerous neurodegenerative diseases. These aberrant proteins disrupt normal neuronal signalling and contribute to impaired cellular homeostasis, including oxidative stress and compromised protein degradation pathways. In essence, ER stress is defined as the cellular response to the accumulation of misfolded proteins in the endoplasmic reticulum, encompassing a series of signalling pathways and molecular events that aim to restore cellular homeostasis. This comprehensive review explores ER stress and its profound implications for the pathogenesis and progression of neurodegenerative diseases.

Identification of Bile Acid-Derived Chemical Chaperone(s) Targeting E46K-Mutated Alpha-Synuclein Protein to Treat Parkinson's Disease: Molecular Modelling, Docking, ADME, and Simulation Studies.

Aggregated α-synuclein (α-syn) present inside small cytoplasmic inclusions in the substantia nigra region marks the major pathological hallmark of Parkinson's disease (PD) and makes it an attractive target for the drug development process. Certain small-molecule chaperones (such as DCA, UDCA, TUDCA) presented the ability to prevent misfolding and aggregation of α-syn as well as to disentangle mature α-syn amyloid fibrils. However, due to toxicity constraints, these small molecules could not be translated into clinical settings. Computational biology methods and bioinformatics approaches allow virtual screening of a large number of molecules, with reduced side effects and better efficacy. In the present study, a library of 10,928 derivatives was generated using DCA, UDCA, and TUDCA bile acid scaffolds and analysed for their binding affinity, pharmacokinetic properties, and drug likeliness profile, to come up with promising compounds with reduced toxicity and better chaperone ability. Molecular docking revealed that with respect to their free binding energy, C1-C25 have the lowest binding energy and bind significantly to recombinantly assembled E46K α-syn fibrils (PDB ID-6UFR). In silico ADME predictions revealed that all these compounds had minimal toxic effects and had good absorption as well as solubility characteristics. Simulation studies further showed that the imidazole ring-based TUDCA derivatives interacted better with the protein in comparison to the others. The proposed study has identified potent chemical chaperones (C2 and C3) as effective therapeutic agents for Parkinson's disease, and further in vitro and in vivo testing will be undertaken to substantiate their potential as novel drugs.

Protein misfolding, ER stress and chaperones: an approach to develop chaperone-based therapeutics for Alzheimer's disease.

Alzheimer's disease (AD) is a heterogeneous neurodegenerative disorder with complex etiology that eventually leads to dementia. The main culprit of AD is the extracellular deposition of ß-amyloid (Aß) and intracellular neurofibrillary tangles. The protein conformational change and protein misfolding are the key events of AD pathophysiology; therefore, endoplasmic reticulum (ER) stress is an apparent consequence. ER, stress-induced unfolded protein response (UPR) mediators (viz. PERK, IRE1, and ATF6) have been reported widely in the AD brain. Considering these factors, preventing protein misfolding or aggregation of tau or amyloidogenic proteins appears to be the best approach to halt its pathogenesis. Therefore, therapies through chemical and pharmacological chaperones came to light as an alternative for the treatment of AD. Diverse studies have demonstrated 4-phenylbutyric acid (4-PBA) as a potential therapeutic agent in AD. The current review outlined the mechanism of protein misfolding, different etiological features behind the progression of AD, the significance of ER stress in AD, and the potential therapeutic role of different chaperones to counter AD. The study also highlights the gaps in current knowledge of the chaperones-based therapeutic approach and the possibility of developing chaperones as a potential therapeutic agent for AD treatment.

Genetic comparison among various coronavirus strains for the identification of potential vaccine targets of SARS-CoV2.

On-going pandemic pneumonia outbreak COVID-19 has raised an urgent public health issue worldwide impacting millions of people with a continuous increase in both morbidity and mortality. The causative agent of this disease is identified and named as SARS-CoV2 because of its genetic relatedness to SARS-CoV species that was responsible for the 2003 coronavirus outbreak. The immense spread of the disease in a very small period demands urgent development of therapeutic and prophylactic interventions for the treatment of SARS-CoV2 infected patients. A plethora of research is being conducted globally on this novel coronavirus strain to gain knowledge about its origin, evolutionary history, and phylogeny. This review is an effort to compare genetic similarities and diversifications among coronavirus strains, which can hint towards the susceptible antigen targets of SARS-CoV2 to come up with the potential therapeutic and prophylactic interventions for the prevention of this public threat.