Acetaminophen induces mitochondrial apoptosis through proteasome dysfunctions.

Acetaminophen is a known antipyretic and non-opioid analgesic for mild pain and fever. Numerous studies uncover their hidden chemotherapeutics applications, including chronic cancer pain management. Acetaminophen also represents an anti-proliferative effect in some cancer cells. Few studies also suggest that the use of Acetaminophen can trigger apoptosis and impede cellular growth. However, Acetaminophen's molecular potential and precise mechanism against improper cellular proliferation and use as an effective anti-proliferative agent still need to be better understood. Here, our current findings show that Acetaminophen induces proteasomal dysfunctions, resulting in aberrant protein accumulation and mitochondrial abnormalities, and consequently induces cell apoptosis. We observed that the Acetaminophen treatment leads to improper aggregation of ubiquitylated expanded polyglutamine proteins, which may be due to the dysfunctions of proteasome activities. Our in-silico analysis suggests the interaction of Acetaminophen and proteasome. Furthermore, we demonstrated the accumulation of proteasome substrates and the depletion of proteasome activities after treating Acetaminophen in cells. Acetaminophen induces proteasome dysfunctions and mitochondrial abnormalities, leading to pro-apoptotic morphological changes and apoptosis successively. These results suggest that Acetaminophen can induce cell death and may retain a promising anti-proliferative effect. These observations can open new possible molecular strategies in the near future for developing and designing specific and effective proteasome inhibitors, which can be helpful in conjugation with other anti-tumor drugs for their better efficiency.

Lanosterol elevates cytoprotective response through induced-proteasomal degradation of aberrant proteins.

Efficient protein synthesis is a basic requirement of our cells to replace the old or defective proteins from the intrinsic crowded biomolecular environment. The interconnection among synthesis, folding, and degradation of proteins represents central paradigm to proteostasis. Failure of protein quality control (PQC) mechanisms results in the disturbance and inadequate functions of proteome. The consequent misfolded protein accumulation can form the basis of neurodegeneration onset and largely represents imperfect aging. Understanding how cells improve the function of deregulated PQC mechanisms to establish and maintain proteostasis against the unwanted sequestration of normal proteins with misfolded proteinaceous inclusions is a major challenge. Here we show that treatment of Lanosterol, a cholesterol synthesis pathway intermediate, induces Proteasome proteolytic activities and, therefore, supports the PQC mechanism for the elimination of intracellular aberrant proteins. The exposure of Lanosterol not only promotes Proteasome catalytic functions but also elevates the removal of both bona fide and neurodegenerative diseases associated toxic proteins. Our current study suggests that increasing Proteasome functions with the help of small molecules such as Lanosterol could serve as a cytoprotective therapeutic approach against abnormal protein accumulation. Cumulatively, based on findings in this study, we can understand the critical importance of small molecules and their potential therapeutic influence in re-establishing disturbed proteostasis linked with neurodegeneration.

Trehalose Promotes Clearance of Proteotoxic Aggregation of Neurodegenerative Disease-Associated Aberrant Proteins.

Accumulation of misfolded proteins compromises overall cellular health and fitness. The failure to remove misfolded proteins is a critical reason for their unwanted aggregation in dense cellular protein pools. The accumulation of various inclusions serves as a clinical feature for neurodegenerative diseases. Previous findings suggest that different cellular compartments can store these abnormal inclusions. Studies of transgenic mice and cellular models of neurodegenerative diseases indicate that depleted chaperone capacity contributes to the aggregation of damaged or aberrant proteins, which consequently disturb proteostasis and cell viability. However, improving these abnormal proteins' selective elimination is yet to be well understood. Still, molecular strategies that can promote the effective degradation of abnormal proteins without compromising cellular viability are unclear. Here, we reported that the trehalose treatment elevates endogenous proteasome levels and enhances the activities of the proteasome. Trehalose-mediated proteasomal activation elevates the removal of both bona fide misfolded and various neurodegenerative disease-associated proteins. Our current study suggests that trehalose may retain a proteasome activation potential, which seems helpful in the solubilization of different mutant misfolded proteins, improving cell viability. These results reveal a possible molecular approach to reduce the overload of intracellular misfolded proteins, and such cytoprotective functions may play a critical role against protein conformational diseases.

Molecular Chaperones' Potential against Defective Proteostasis of Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neuronal degenerative condition identified via a build-up of mutant aberrantly folded proteins. The native folding of polypeptides is mediated by molecular chaperones, preventing their pathogenic aggregation. The mutant protein expression in ALS is linked with the entrapment and depletion of chaperone capacity. The lack of a thorough understanding of chaperones' involvement in ALS pathogenesis presents a significant challenge in its treatment. Here, we review how the accumulation of the ALS-linked mutant FUS, TDP-43, SOD1, and C9orf72 proteins damage cellular homeostasis mechanisms leading to neuronal loss. Further, we discuss how the HSP70 and DNAJ family co-chaperones can act as potential targets for reducing misfolded protein accumulation in ALS. Moreover, small HSPB1 and HSPB8 chaperones can facilitate neuroprotection and prevent stress-associated misfolded protein apoptosis. Designing therapeutic strategies by pharmacologically enhancing cellular chaperone capacity to reduce mutant protein proteotoxic effects on ALS pathomechanisms can be a considerable advancement. Chaperones, apart from directly interacting with misfolded proteins for protein quality control, can also filter their toxicity by initiating strong stress-response pathways, modulating transcriptional expression profiles, and promoting anti-apoptotic functions. Overall, these properties of chaperones make them an attractive target for gaining fundamental insights into misfolded protein disorders and designing more effective therapies against ALS.

Disturb mitochondrial associated proteostasis: Neurodegeneration and imperfect ageing.

The disturbance in mitochondrial functions and homeostasis are the major features of neuron degenerative conditions, like Parkinson's disease, Amyotrophic Lateral Sclerosis, and Alzheimer's disease, along with protein misfolding. The aberrantly folded proteins are known to link with impaired mitochondrial pathways, further contributing to disease pathogenesis. Despite their central significance, the implications of mitochondrial homeostasis disruption on other organelles and cellular processes remain insufficiently explored. Here, we have reviewed the dysfunction in mitochondrial physiology, under neuron degenerating conditions. The disease misfolded proteins impact quality control mechanisms of mitochondria, such as fission, fusion, mitophagy, and proteasomal clearance, to the detriment of neuron. The adversely affected mitochondrial functional roles, like oxidative phosphorylation, calcium homeostasis, and biomolecule synthesis as well as its axes and contacts with endoplasmic reticulum and lysosomes are also discussed. Mitochondria sense and respond to multiple cytotoxic stress to make cell adapt and survive, though chronic dysfunction leads to cell death. Mitochondria and their proteins can be candidates for biomarkers and therapeutic targets. Investigation of internetworking between mitochondria and neurodegeneration proteins can enhance our holistic understanding of such conditions and help in designing more targeted therapies.

Itraconazole Confers Cytoprotection Against Neurodegenerative Disease-Associated Abnormal Protein Aggregation.

Cells perform regular maintenance to avoid the accumulation of misfolded proteins. Prolonged accumulation of these proteotoxic inclusions generates potential risk of ageing-related diseases such as neurodegenerative diseases. Therefore, removal of such abnormal aggregates can ensure the re-establishment of proteostasis. Ubiquitin proteasome system (UPS) actively participates in the selective removal of aberrantly folded clients with the help of complex proteasome machinery. However, specific induction of proteasome functions to remove abnormal proteins remains an open challenge. Here, we show that Itraconazole treatment induces proteasome activities and degrades the accumulation of bonafide-misfolded proteins, including heat-denatured luciferase. Exposure of Itraconazole elevates the degradation of neurodegenerative disease-associated proteins, e.g. expanded polyglutamine, mutant SOD1, and mutant α-synuclein. Our results suggest that Itraconazole treatment prevents the accumulation of neurodegenerative disease-linked misfolded proteins and generates cytoprotection. These findings reveal that Itraconazole removes abnormal proteins through sequential proteasomal activation and represents a potential protective therapeutic role against protein-misfolding neurodegenerative diseases.

Resveratrol Promotes LRSAM1 E3 Ubiquitin Ligase-Dependent Degradation of Misfolded Proteins Linked with Neurodegeneration.

BACKGROUND/AIMS: Cells require regular maintenance of proteostasis. Synthesis of new polypeptides and elimination of damaged or old proteins is an uninterrupted mechanism essential for a healthy cellular environment. Impairment in the removal of misfolded proteins can disturb proteostasis; such toxic aggregation of misfolded proteins can act as a primary risk factor for neurodegenerative diseases and imperfect ageing. The critical challenge is to design effective protein quality control (PQC) based molecular tactics that could potentially eliminate aggregation-prone protein load from the cell. Still, targeting specific components of the PQC pathway for the suppression of proteotoxic insults retains several challenges. Earlier, we had observed that LRSAM1 promotes the degradation of aberrant proteins. Here, we examined the effect of resveratrol, a stilbenoid phytoalexin compound, treatment on LRSAM1 E3 ubiquitin ligase, involved in the spongiform neurodegeneration. METHODS: In this study, we reported induction of mRNA and protein levels of LRSAM1 in response to resveratrol treatment via RT-PCR, immunoblotting, and immunofluorescence analysis. The LRSAM1-mediated proteasomal-based clearance of misfolded proteins was also investigated via proteasome activity assays, immunoblotting and immunofluorescence analysis. The increased stability of LRSAM1 by resveratrol was demonstrated by cycloheximide chase analysis. RESULTS: Here, we show that resveratrol treatment induces LRSAM1 E3 ubiquitin ligase expression levels. Further, our findings suggest that overexpression of LRSAM1 significantly elevates proteasome activities and improves the degradation of bona fide heat-denatured luciferase protein. Exposure of resveratrol not only slows down the turnover of LRSAM1 but also effectively degrades abnormal proteinaceous inclusions, which eventually promotes cell viability. CONCLUSION: Our findings suggest that resveratrol facilitates LRSAM1 endogenous establishment, which consequently promotes the proteasome machinery for effective removal of intracellular accumulated misfolded or proteasomal-designated substrates. Altogether, our study proposes a promising molecular approach to specifically trigger PQC signaling for efficacious rejuvenation of defective proteostasis via activation of overburdened proteolytic machinery.

Improper Proteostasis: Can It Serve as Biomarkers for Neurodegenerative Diseases?

Cells synthesize new proteins after multiple molecular decisions. Damage of existing proteins, accumulation of abnormal proteins, and basic requirement of new proteins trigger protein quality control (PQC)-based alternative strategies to cope against proteostasis imbalance. Accumulation of misfolded proteins is linked with various neurodegenerative disorders. However, how deregulated components of this quality control system and their lack of general mechanism-based long-term changes can serve as biomarkers for neurodegeneration remains largely unexplored. Here, our article summarizes the chief findings, which may facilitate the search of novel and relevant proteostasis mechanism-based biomarkers associated with neuronal disorders. Understanding the abnormalities of PQC coupled molecules as possible biomarkers can help to determine neuronal fate and their contribution to the aetiology of several nervous system disorders.

Autophagy based cellular physiological strategies target oncogenic progression.

Evidence accumulated from past findings indicates that defective proteostasis may contribute to risk factors for cancer generation. Irregular assembly of abnormal proteins catalyzes the disturbance of cellular proteostasis and induces the ability of abnormal cellular proliferation. The autophagy mechanism plays a key role in the regular clearance of abnormal/poor lipids, proteins, and various cellular organelles. The results of functional and effective autophagy deliver normal cellular homeostasis, which establishes supportive metabolism and avoids unexpected tumorigenesis events. Still, the precise molecular mechanism of autophagy in tumor suppression has not been clear. How autophagy triggers selective or nonselective bulk degradation to dissipate tumor promotion under stress conditions is not clear. Under proteotoxic insults to knockdown the drive of tumorigenesis, it is critical for us to figure out the detailed molecular functions of autophagy in human cancers. The current article summarizes autophagy-based theragnostic strategies targeting various phases of tumorigenesis and suggests the preventive roles of autophagy against tumor progression. A better understanding of various molecular partners of autophagic flux will improve and innovate therapeutic approaches based on autophagic-susceptible effects against cellular oncogenic transformation.

Biochemical strategies of E3 ubiquitin ligases target viruses in critical diseases.

Viruses are known to cause various diseases in human and also infect other species such as animal plants, fungi, and bacteria. Replication of viruses depends upon their interaction with hosts. Human cells are prone to such unwanted viral infections. Disintegration and reconstitution require host machinery and various macromolecules like DNA, RNA, and proteins are invaded by viral particles. E3 ubiquitin ligases are known for their specific function, that is, recognition of their respective substrates for intracellular degradation. Still, we do not understand how ubiquitin proteasome system-based enzymes E3 ubiquitin ligases do their functional interaction with different viruses. Whether E3 ubiquitin ligases help in the elimination of viral components or viruses utilize their molecular capabilities in their intracellular propagation is not clear. The first time our current article comprehends fundamental concepts and new insights on the different viruses and their interaction with various E3 Ubiquitin Ligases. In this review, we highlight the molecular pathomechanism of viruses linked with E3 Ubiquitin Ligases dependent mechanisms. An enhanced understanding of E3 Ubiquitin Ligase-mediated removal of viral proteins may open new therapeutic strategies against viral infections.

Proteasome Based Molecular Strategies Against Improper Cellular Proliferation.

Cells contain several proteins that routinely fulfill multiple requirements for normal physiological survival. Proteostasis dysfunction is linked with different complex human disorders, like cancer, neuron degeneration, and imperfect aging. The ubiquitin proteasome system (UPS) forms the primary proteostasis mechanism taking part in cytoprotection. Cancer cells are well known to possess enhanced cytoprotective properties, and different UPS elements are implicated to be dysregulated at several stages of tumor progression. Furthermore, many studies have found tumor cells to exhibit higher levels of various UPS components, possibly contributing to their robust endurance. In this article, we have presented different cellular protein quality control strategies, essential for maintaining healthy proteome. Here, we have also discussed key contributions and functions of UPS involved in molecular pathomechanisms for establishing cancer conditions. Along with this, the emerging different therapeutic strategies against defective proteome linked with improper cellular proliferation and cancer progression are also reviewed. UPS performs critical regulatory functions in modulating the cellular apoptotic pathways. The proteasomal system involvement as probable therapeutic targets influencing cancer cell apoptosis is also discussed. Our article summarizes the recent developments in proteasome-associated pathways regulating tumor cell proteome and survival. Additionally, how the engagement and cross functions of these physiological processes can induce apoptosis and may develop regulation over tumor progression. A better understanding of multifaceted protein quality control pathways may inform therapeutic interventions based on cellular proteostasis response determined against complex diseases.