Muscular atrophy (MA) is a disease of various origins, i.e., genetic or the most common, caused by mechanical injury. So far, there is no universal therapeutic model because this disease is often progressive with numerous manifested symptoms. Moreover, there is no safe and low-risk therapy dedicated to muscle atrophy. For this reason, our research focuses on finding an alternative method using natural compounds to treat MA. This study proposes implementing natural substances such as celastrol and Rhynchophylline on the cellular level, using a simulated and controlled atrophy process. Methods: Celastrol and Rhynchophylline were used as natural compounds against simulated atrophy in C2C12 cells. Skeletal muscle C2C12 cells were stimulated for the differentiation process. Atrophic conditions were obtained by the exposure to the low concertation of doxorubicin and validated by FoxO3 and MAFbx. The protective and regenerative effect of drugs on cell proliferation was determined by the MTT assay and MT-CO1, VDAC1, and prohibitin expression. Results: The obtained results revealed that both natural substances reduced atrophic symptoms. Rhynchophylline and celastrol attenuated atrophic cells in the viability studies, morphology analysis by diameter measurements, modulated prohibitin VDAC, and MT-CO1 expression. Conclusions: The obtained results revealed that celastrol and Rhynchophylline could be effectively used as a supportive treatment in atrophy-related disorders. Thus, natural drugs seem promising for muscle regeneration.

Heat shock factor 1 (HSF1) is a master transcription regulator that mediates the induction of heat shock protein chaperones for quality control (QC) of the proteome and maintenance of proteostasis as a protective mechanism in response to stress. Research in this particular area has accelerated dramatically over the past three decades following successful isolation, cloning, and characterization of HSF1. The intricate multi-protein complexes and transcriptional activation orchestrated by HSF1 are fundamental processes within the cellular QC machinery. Our primary focus is on the regulation and function of HSF1 in aging and neurodegenerative diseases (ND) which represent physiological and pathological states of dysfunction in protein QC. This chapter presents an overview of HSF1 structural, functional, and energetic properties in healthy cells while addressing the deterioration of HSF1 function viz-à-viz age-dependent and neuron-specific vulnerability to ND. We discuss the structural domains of HSF1 with emphasis on the intrinsically disordered regions and note that disease proteins associated with ND are often structurally disordered and exquisitely sensitive to changes in cellular environment as may occur during aging. We propose a hypothesis that age-dependent changes of the intrinsically disordered proteome likely hold answers to understand many of the functional, structural, and organizational changes of proteins and signaling pathways in aging - dysfunction of HSF1 and accumulation of disease protein aggregates in ND included.Structured AbstractsIntroduction: Heat shock factor 1 (HSF1) is a master transcription regulator that mediates the induction of heat shock protein chaperones for quality control (QC) of the proteome as a cyto-protective mechanism in response to stress. There is cumulative evidence of age-related deterioration of this QC mechanism that contributes to disease vulnerability.
OBJECTIVE: Herein we discuss the regulation and function of HSF1 as they relate to the pathophysiological changes of protein quality control in aging and neurodegenerative diseases (ND).
METHODS: We present an overview of HSF1 structural, functional, and energetic properties in healthy cells while addressing the deterioration of HSF1 function vis-à-vis age-dependent and neuron-specific vulnerability to neurodegenerative diseases.
RESULTS: We examine the impact of intrinsically disordered regions on the function of HSF1 and note that proteins associated with neurodegeneration are natively unstructured and exquisitely sensitive to changes in cellular environment as may occur during aging.
CONCLUSIONS: We put forth a hypothesis that age-dependent changes of the intrinsically disordered proteome hold answers to understanding many of the functional, structural, and organizational changes of proteins - dysfunction of HSF1 in aging and appearance of disease protein aggregates in neurodegenerative diseases included.

Cells have different sets of molecules for performing an array of physiological functions. Nucleic acids have stored and carried the information throughout evolution, whereas proteins have been attributed to performing most of the cellular functions. To perform these functions, proteins need to have a unique conformation and a definite lifespan. These attributes are achieved by a highly coordinated protein quality control (PQC) system comprising chaperones to fold the proteins in a proper three-dimensional structure, ubiquitin-proteasome system for selective degradation of proteins, and autophagy for bulk clearance of cell debris. Many kinds of stresses and perturbations may lead to the weakening of these protective cellular machinery, leading to the unfolding and aggregation of cellular proteins and the occurrence of numerous pathological conditions. However, modulating the expression and functional efficiency of molecular chaperones, E3 ubiquitin ligases, and autophagic proteins may diminish cellular proteotoxic load and mitigate various pathological effects. Natural medicine and small molecule-based therapies have been well-documented for their effectiveness in modulating these pathways and reestablishing the lost proteostasis inside the cells to combat disease conditions. The present article summarizes various similar reports and highlights the importance of the molecules obtained from natural sources in disease therapeutics.

Health span is driven by a precise interplay between genes and the environment. Cell response to environmental cues is mediated by signaling cascades and genetic variants that affect gene expression by regulating chromatin plasticity. Indeed, they can promote the interaction of promoters with regulatory elements by forming active chromatin hubs. FOXO3 encodes a transcription factor with a strong impact on aging and age-related phenotypes, as it regulates stress response, therefore affecting lifespan. A significant association has been shown between human longevity and several FOXO3 variants located in intron 2. This haplotype block forms a putative aging chromatin hub in which FOXO3 has a central role, as it modulates the physical connection and activity of neighboring genes involved in age-related processes. Here we describe the role of FOXO3 and its single-nucleotide polymorphisms (SNPs) in healthy aging, with a focus on the enhancer region encompassing the SNP rs2802292, which upregulates FOXO3 expression and can promote the activity of the aging hub in response to different stress stimuli. FOXO3 protective effect on lifespan may be due to the accessibility of this region to transcription factors promoting its expression. This could in part explain the differences in FOXO3 association with longevity between genders, as its activity in females may be modulated by estrogens through estrogen receptor response elements located in the rs2802292-encompassing region. Altogether, the molecular mechanisms described here may help establish whether the rs2802292 SNP can be taken advantage of in predictive medicine and define the potential of targeting FOXO3 for age-related diseases.

Spinal cord and peripheral nerve injury results in extensive damage to the locally injured cells as well as distant cells that are functionally connected to them. Both primary and secondary damage can cause a broad range of clinical abnormalities, including neuropathic pain and cognitive and memory dysfunction. However, the mechanisms underlying these abnormalities remain unclear, awaiting new methods to identify affected cells to enable examination of their molecular, cellular and physiological characteristics. Here, we report that both primary and secondary damage to cells in mouse models of spinal cord and peripheral nerve injury can be detected in vivo using a novel fluorescent reporter system based on the immediate stress response via activation of Heat Shock Factor 1. We also provide evidence for altered electrophysiological properties of reporter-positive secondarily-injured neurons. The comprehensive identification of injured, but surviving cells located both close and at distant locations from the injury site in vivo will provide a way to study their pathophysiology and possibly prevention of their further deterioration.

Heat shock response is an adaptive mechanism of cells characterized by rapid synthesis of a class of proteins popularly known as heat shock proteins (HSPs) by heat-induced activation of Heat Shock Factor 1 (HSF1). In course of our earlier study to show that HSF1 regulates transcription of HYPK (Huntingtin Yeast two-hybrid protein K), a chaperone-like protein, we observed presence of few other genes within 10 kb of HYPK promoter. In an attempt to understand whether adjacent genes of HYPK are co-regulated, we identified that SERF2 (small EDRK-rich factor 2), an upstream neighboring gene of HYPK, is also regulated by heat stress and HSF1. We also showed that SERF2 promoter can be trans-activated by HSF1 due to the presence of functional heat shock element (HSE). Strikingly, HYPK is linked with SERF2 through a Conjoined Gene (CG) albeit the respective proteins have opposite effect on mutant Huntingtin aggregates and subsequent toxicity. Our study provides the first report on regulation of SERF2 expression and thereby depicts a paradigm where two parent genes of a CG are regulated by a common transcription factor despite the fact that they code for proteins having opposite cellular function in a given context.

Adaptive thermogenesis allows mammals to resist to cold. For instance, in brown adipose tissue (BAT) the facultative uncoupling of the proton gradient from ATP synthesis in mitochondria is used to generate systemic heat. However, this system necessitates an increase of the Uncoupling protein 1 (Ucp1) and its activation by free fatty acids. Here we show that mice without functional Period2 (Per2) were cold sensitive because their adaptive thermogenesis system was less efficient. Upon cold-exposure, Heat shock factor 1 (HSF1) induced Per2 in the BAT. Subsequently, PER2 as a co-activator of PPARα increased expression of Ucp1. PER2 also increased Fatty acid binding protein 3 (Fabp3), a protein important to transport free fatty acids from the plasma to mitochondria to activate UCP1. Hence, in BAT PER2 is important for the coordination of the molecular response of mice exposed to cold by synchronizing UCP1 expression and its activation.