Gallic acid triphenylphosphonium derivatives TPP+-C10 and TPP+-C12 inhibit mitochondrial function in Candida albicans exerting antifungal and antibiofilm effects.

AIMS: To evaluate the antifungal and antibiofilm activity of gallic acid derivatives TPP+-C10 and TPP+-C12 and their effects on mitochondrial function on two Candida albicans reference strains (ATCC 90029 and ATCC 10231). METHODS AND RESULTS: First, we determined minimal inhibitory concentration (MIC) using a microdilution assay. Both compounds exerted antifungal effects, and their MICs ranged from 3.9 to 13 µM, with no statistically significant differences between them (P > 0.05, t-test). These concentrations served as references for following assays. Subsequently, we measured oxygen consumption with a Clark electrode. Our observations revealed that both drugs inhibited oxygen consumption in both strains with TPP+-C12 exerting a more pronounced inhibitory effect. We then employed flow cytometry with TMRE as a probe to assess mitochondrial membrane potential. For each strain assayed, the compounds induced a decay in transmembrane potential by 75%-90% compared to the control condition (P < 0.05, ANOVA). Then, we measured ATP levels using a commercial kit. TPP+-C12 showed a 50% decrease of ATP content (P < 0.05 ANOVA), while TPP+-C10 exhibited a less pronounced effect. Finally, we assessed the antibiofilm effect using the MTT reduction assay. Both compounds were effective, but TPP+-C12 displayed a greater potency, requiring a lower concentration to inhibit 50% of biofilms viability (P < 0.05, t-test). CONCLUSIONS: Derivatives of gallic acid linked to a TPP+ group exert antifungal and antibiofilm activity through impairment of mitochondrial function in C. albicans.

Proteomic profile of human gingival crevicular fluid reveals specific biological and molecular processes during clinical progression of periodontitis.

BACKGROUND AND OBJECTIVE: There is no clear understanding of molecular events occurring in the periodontal microenvironment during clinical disease progression. Our aim was to explore qualitative and quantitative differences in gingival crevicular fluid (GCF) protein profiles from patients diagnosed with periodontitis between non-progressive and progressive periodontal sites. METHODS: Five systemically healthy patients diagnosed with periodontitis were monitored weekly in their progression of the disease and GCF samples from 10 candidate sites were obtained. Two groups of five sites, matched from an equal number of teeth, were selected from the five patients: Progression (PG) and Non-Progression (NP). Global protein identification was performed with high-throughput proteomic approaches and label-free analysis determined their relative abundances. Proteins were identified by Proteome Discoverer v2.4 and searched against human SwissProt protein databases. Enrichment bioinformatic analyses were performed in STRING-DB and ShinyGO environment. RESULTS: 1504 and 1500 proteins were identified in NP and PG respectively. Forty-eight proteins were exclusively identified in PG, while 52 were identified in NP. Moreover, 35 proteins were more abundant in PG and 29 proteins in NP (twofold change, p < .05). The NP group was mainly represented by proteins from "response to biotic stimuli and other organisms," "processes of cell death regulation," "peptidase regulation," "protein ubiquitination," and "ribosomal activity" GO categories. The most represented GO categories of the PG group were "assembly of multiprotein complexes," "catabolic processes," "lipid metabolism," and "binding to hemoglobin and haptoglobin." CONCLUSIONS: There are quantitative and qualitative differences in the proteome of GCF from periodontal sites according to the status of clinical progression of periodontitis. Progressive periodontitis sites are characterized by a protein profile associated with catabolic processes, immune response, and response to cellular stress, while stable periodontitis sites show a protein profile mainly related to wound repair and healing processes, cell death regulation, and chaperone-mediated autophagy. Understanding the etiopathogenic role of these profiles in progressive periodontitis may help to develop new diagnostic and therapeutic approaches.

TDP-43 loss of cellular function through aggregation requires additional structural determinants beyond its C-terminal Q/N prion-like domain.

TDP-43 aggregates are the neurohistological landmark of diseases like amyotrophic lateral sclerosis and frontotemporal dementia. Their role in the pathogenesis of these conditions is not yet clear mainly due to the lack of proper models of aggregation that may allow the study of the mechanism of formation, their interactions with other cellular components and their effect on the cell metabolism. In this work, we have used tandem repeats of the prion like Q/N-rich region of TAR DNA-binding protein (TDP-43) fused to additional TDP-43 protein sequences to trigger aggregate formation in neuronal and non-neuronal cell lines. At the functional level, these aggregates are able to sequester endogenous TDP-43 depleting its nuclear levels and inducing loss of function at the pre-mRNA splicing level. No apparent direct cellular toxicity of the aggregates seems to be present beyond the lack of functional TDP-43. To our knowledge, this is the only system that achieves full functional TDP 43 depletion with effects similar to RNAi depletion or gene deletion. As a result, this model will prove useful to investigate the loss-of-function effects mediated by TDP-43 aggregation within cells without affecting the expression of the endogenous gene. We have identified the N-terminus sequence of TDP-43 as the domain that enhances its interaction with the aggregates and its insolubilization. These data show for the first time that cellular TDP-43 aggregation can lead to total loss of function and to defective splicing of TDP-43-dependent splicing events in endogenous genes.

Aggregate formation prevents dTDP-43 neurotoxicity in the Drosophila melanogaster eye.

TDP-43 inclusions are an important histopathological feature in various neurodegenerative disorders, including Amyotrophic Lateral Sclerosis and Fronto-Temporal Lobar Degeneration. However, the relation of these inclusions with the pathogenesis of the disease is still unclear. In fact, the inclusions could be toxic themselves, induce loss of function by sequestering TDP-43 or a combination of both. Previously, we have developed a cellular model of aggregation using the TDP-43 Q/N rich amino acid sequence 331-369 repeated 12 times (12xQ/N) and have shown that these cellular inclusions are capable of sequestering the endogenous TDP-43 both in non-neuronal and neuronal cells. We have tested this model in vivo in the Drosophila melanogaster eye. The eye structure develops normally in the absence of dTDP-43, a fact previously seen in knock out fly strains. We show here that expression of EGFP 12xQ/N does not alter the structure of the eye. In contrast, TBPH overexpression is neurotoxic and causes necrosis and loss of function of the eye. More important, the neurotoxicity of TBPH can be abolished by its incorporation to the insoluble aggregates induced by EGFP 12xQ/N. This data indicates that aggregation is not toxic per se and instead has a protective role, modulating the functional TBPH available in the tissue. This is an important indication for the possible pathological mechanism in action on ALS patients.

A multi-platform analysis of human gingival crevicular fluid reveals ferroptosis as a relevant regulated cell death mechanism during the clinical progression of periodontitis.

Ferroptosis is implicated in the pathogenesis of numerous chronic-inflammatory diseases, yet its association with progressive periodontitis remains unexplored. To investigate the involvement and significance of ferroptosis in periodontitis progression, we assessed sixteen periodontitis-diagnosed patients. Disease progression was clinically monitored over twelve weeks via weekly clinical evaluations and gingival crevicular fluid (GCF) collection was performed for further analyses. Clinical metrics, proteomic data, in silico methods, and bioinformatics tools were combined to identify protein profiles linked to periodontitis progression and to explore their potential connection with ferroptosis. Subsequent western blot analyses validated key findings. Finally, a single-cell RNA sequencing (scRNA-seq) dataset (GSE164241) for gingival tissues was analyzed to elucidate cellular dynamics during periodontitis progression. Periodontitis progression was identified as occurring at a faster rate than traditionally thought. GCF samples from progressing and non-progressing periodontal sites showed quantitative and qualitatively distinct proteomic profiles. In addition, specific biological processes and molecular functions during progressive periodontitis were revealed and a set of hub proteins, including SNCA, CA1, HBB, SLC4A1, and ANK1 was strongly associated with the clinical progression status of periodontitis. Moreover, we found specific proteins - drivers or suppressors - associated with ferroptosis (SNCA, FTH1, HSPB1, CD44, and GCLC), revealing the co-occurrence of this specific type of regulated cell death during the clinical progression of periodontitis. Additionally, the integration of quantitative proteomic data with scRNA-seq analysis suggested the susceptibility of fibroblasts to ferroptosis. Our analyses reveal proteins and processes linked to ferroptosis for the first time in periodontal patients, which offer new insights into the molecular mechanisms of progressive periodontal disease. These findings may lead to novel diagnostic and therapeutic strategies.

PKD2 regulates autophagy and forms a protein complex with BECN1 at the primary cilium of hypothalamic neuronal cells.

The primary cilium, hereafter cilium, is an antenna-like organelle that modulates intracellular responses, including autophagy, a lysosomal degradation process essential for cell homeostasis. Dysfunction of the cilium is associated with impairment of autophagy and diseases known as "ciliopathies". The discovery of autophagy-related proteins at the base of the cilium suggests its potential role in coordinating autophagy initiation in response to physiopathological stimuli. One of these proteins, beclin-1 (BECN1), it which is necessary for autophagosome biogenesis. Additionally, polycystin-2 (PKD2), a calcium channel enriched at the cilium, is required and sufficient to induce autophagy in renal and cancer cells. We previously demonstrated that PKD2 and BECN1 form a protein complex at the endoplasmic reticulum in non-ciliated cells, where it initiates autophagy, but whether this protein complex is present at the cilium remains unknown. Anorexigenic pro-opiomelanocortin (POMC) neurons are ciliated cells that require autophagy to maintain intracellular homeostasis. POMC neurons are sensitive to metabolic changes, modulating signaling pathways crucial for controlling food intake. Exposure to the saturated fatty acid palmitic acid (PA) reduces ciliogenesis and inhibits autophagy in these cells. Here, we show that PKD2 and BECN1 form a protein complex in N43/5 cells, an in vitro model of POMC neurons, and that both PKD2 and BECN1 locate at the cilium. In addition, our data show that the cilium is required for PKD2-BECN1 protein complex formation and that PA disrupts the PKD2-BECN1 complex, suppressing autophagy. Our findings provide new insights into the mechanisms by which the cilium controls autophagy in hypothalamic neuronal cells.

Cellular model of TAR DNA-binding protein 43 (TDP-43) aggregation based on its C-terminal Gln/Asn-rich region.

TDP-43 is one of the major components of the neuronal and glial inclusions observed in several neurodegenerative diseases such as amyotrophic lateral sclerosis and frontotemporal lobar degeneration. These characteristic aggregates are a "landmark" of the disease, but their role in the pathogenesis is still obscure. In previous works, we have shown that the C-terminal Gln/Asn-rich region (residues 321-366) of TDP-43 is involved in the interaction of this protein with other members of the heterogeneous nuclear ribonucleoprotein protein family. Furthermore, we have shown that the interaction through this region is important for TDP-43 splicing inhibition of cystic fibrosis transmembrane regulator exon 9, and there were indications that it was involved in the aggregation process. Our experiments show that in cell lines and primary rat neuronal cultures, the introduction of tandem repeats carrying the 331-369-residue Gln/Asn region from TDP-43 can trigger the formation of phosphorylated and ubiquitinated aggregates that recapitulate many but not all the characteristics observed in patients. These results establish a much needed cell-based TDP-43 aggregation model useful to investigate the mechanisms involved in the formation of inclusions and the gain- and loss-of-function consequences of TDP-43 aggregation within cells. In addition, it will be a powerful tool to test novel therapeutic strategies/effectors aimed at preventing/reducing this phenomenon.

Administration of Secretome Derived from Human Mesenchymal Stem Cells Induces Hepatoprotective Effects in Models of Idiosyncratic Drug-Induced Liver Injury Caused by Amiodarone or Tamoxifen.

Drug-induced liver injury (DILI) is one of the leading causes of acute liver injury. While many factors may contribute to the susceptibility to DILI, obese patients with hepatic steatosis are particularly prone to suffer DILI. The secretome derived from mesenchymal stem cell has been shown to have hepatoprotective effects in diverse in vitro and in vivo models. In this study, we evaluate whether MSC secretome could improve DILI mediated by amiodarone (AMI) or tamoxifen (TMX). Hepatic HepG2 and HepaRG cells were incubated with AMI or TMX, alone or with the secretome of MSCs obtained from human adipose tissue. These studies demonstrate that coincubation of AMI or TMX with MSC secretome increases cell viability, prevents the activation of apoptosis pathways, and stimulates the expression of priming phase genes, leading to higher proliferation rates. As proof of concept, in a C57BL/6 mouse model of hepatic steatosis and chronic exposure to AMI, the MSC secretome was administered endovenously. In this study, liver injury was significantly attenuated, with a decrease in cell infiltration and stimulation of the regenerative response. The present results indicate that MSC secretome administration has the potential to be an adjunctive cell-free therapy to prevent liver failure derived from DILI caused by TMX or AMI.

Methods for studying primary cilia in heart tissue after ischemia-reperfusion injury.

Cardiovascular diseases are the leading cause of death and disability worldwide. After heart injury triggered by myocardial ischemia or myocardial infarction, extensive zones of tissue are damaged and some of the tissue dies by necrosis and/or apoptosis. The loss of contractile mass activates a series of biochemical mechanisms that allow, through cardiac remodeling, the replacement of the dysfunctional heart tissue by fibrotic material. Our previous studies have shown that primary cilia, non-motile antenna-like structures at the cell surface required for the activation of specific signaling pathways, are present in cardiac fibroblasts and required for cardiac fibrosis induced by ischemia/reperfusion (I/R) in mice. I/R-induced myocardial fibrosis promotes the enrichment of ciliated cardiac fibroblasts where the myocardial injury occurs. Given discussions about the existence of cilia in specific cardiac cell types, as well as the functional relevance of studying cilia-dependent signaling in cardiac fibrosis after I/R, here we describe our methods to evaluate the presence and roles of primary cilia in cardiac fibrosis after I/R in mice.

Autophagy in aging-related oral diseases.

Autophagy is an intracellular degradation mechanism that allows recycling of organelles and macromolecules. Autophagic function increases metabolite availability modulating metabolic pathways, differentiation and cell survival. The oral environment is composed of several structures, including mineralized and soft tissues, which are formed by complex interactions between epithelial and mesenchymal cells. With aging, increased prevalence of oral diseases such as periodontitis, oral cancer and periapical lesions are observed in humans. These aging-related oral diseases are chronic conditions that alter the epithelial-mesenchymal homeostasis, disrupting the oral tissue architecture affecting the quality of life of the patients. Given that autophagy levels are reduced with age, the purpose of this review is to discuss the link between autophagy and age-related oral diseases.

Origanum vulgare L. essential oil inhibits virulence patterns of Candida spp. and potentiates the effects of fluconazole and nystatin in vitro.

BACKGROUND: Recurrence and resistance of Candida spp. infections is associated with the ability of these microorganisms to present several virulence patterns such as morphogenesis, adhesion, and biofilm formation. In the search for agents with antivirulence activity, essential oils could represent a strategy to act against biofilms and to potentiate antifungal drugs. OBJECTIVE: To evaluate the antivirulence effect of Origanum vulgare L. essential oil (O-EO) against Candida spp. and to potentiate the effect of fluconazole and nystatin. METHODS: The effect of O-EO was evaluated on ATCC reference strains of C. albicans and non-albicans Candida species. Minimum inhibitory concentration (MIC) was determined through broth microdilution assay. Adhesion to microplates was determined by crystal violet (CV) assay. An adapted scratch assay in 24-well was used to determine the effect of essential oil on biofilms proliferation. Viability of biofilms was evaluated by MTT reduction assay and through a checkerboard assay we determined if O-EO could act synergistically with fluconazole and nystatin. RESULTS: MIC for C. albicans ATCC-90029 and ATCC-10231 was 0.01 mg/L and 0.97 mg/L, respectively. For non-albicans Candida strains MIC values were 2.6 mg/L for C. dubliniensis ATCC-CD36 and 5.3 mg/L for C. krusei ATCC-6258. By using these concentrations, O-EO inhibited morphogenesis, adhesion, and proliferation at least by 50% for the strains assayed. In formed biofilms O-EO decreased viability in ATCC 90029 and ATCC 10231 strains (IC50 7.4 and 2.8 mg/L respectively). Finally, we show that O-EO interacted synergistically with fluconazole and nystatin. CONCLUSIONS: This study demonstrate that O-EO could be considered to improve the antifungal treatment against Candida spp.

Palmitic and Stearic Acids Inhibit Chaperone-Mediated Autophagy (CMA) in POMC-like Neurons In Vitro.

The intake of food with high levels of saturated fatty acids (SatFAs) is associated with the development of obesity and insulin resistance. SatFAs, such as palmitic (PA) and stearic (SA) acids, have been shown to accumulate in the hypothalamus, causing several pathological consequences. Autophagy is a lysosomal-degrading pathway that can be divided into macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA). Previous studies showed that PA impairs macroautophagy function and insulin response in hypothalamic proopiomelanocortin (POMC) neurons. Here, we show in vitro that the exposure of POMC neurons to PA or SA also inhibits CMA, possibly by decreasing the total and lysosomal LAMP2A protein levels. Proteomics of lysosomes from PA- and SA-treated cells showed that the inhibition of CMA could impact vesicle formation and trafficking, mitochondrial components, and insulin response, among others. Finally, we show that CMA activity is important for regulating the insulin response in POMC hypothalamic neurons. These in vitro results demonstrate that CMA is inhibited by PA and SA in POMC-like neurons, giving an overview of the CMA-dependent cellular pathways that could be affected by such inhibition and opening a door for in vivo studies of CMA in the context of the hypothalamus and obesity.

Palmitic acid control of ciliogenesis modulates insulin signaling in hypothalamic neurons through an autophagy-dependent mechanism.

Palmitic acid (PA) is significantly increased in the hypothalamus of mice, when fed chronically with a high-fat diet (HFD). PA impairs insulin signaling in hypothalamic neurons, by a mechanism dependent on autophagy, a process of lysosomal-mediated degradation of cytoplasmic material. In addition, previous work shows a crosstalk between autophagy and the primary cilium (hereafter cilium), an antenna-like structure on the cell surface that acts as a signaling platform for the cell. Ciliopathies, human diseases characterized by cilia dysfunction, manifest, type 2 diabetes, among other features, suggesting a role of the cilium in insulin signaling. Cilium depletion in hypothalamic pro-opiomelanocortin (POMC) neurons triggers obesity and insulin resistance in mice, the same phenotype as mice deficient in autophagy in POMC neurons. Here we investigated the effect of chronic consumption of HFD on cilia; and our results indicate that chronic feeding with HFD reduces the percentage of cilia in hypothalamic POMC neurons. This effect may be due to an increased amount of PA, as treatment with this saturated fatty acid in vitro reduces the percentage of ciliated cells and cilia length in hypothalamic neurons. Importantly, the same effect of cilia depletion was obtained following chemical and genetic inhibition of autophagy, indicating autophagy is required for ciliogenesis. We further demonstrate a role for the cilium in insulin sensitivity, as cilium loss in hypothalamic neuronal cells disrupts insulin signaling and insulin-dependent glucose uptake, an effect that correlates with the ciliary localization of the insulin receptor (IR). Consistently, increased percentage of ciliated hypothalamic neuronal cells promotes insulin signaling, even when cells are exposed to PA. Altogether, our results indicate that, in hypothalamic neurons, impairment of autophagy, either by PA exposure, chemical or genetic manipulation, cause cilia loss that impairs insulin sensitivity.

Chaperone Mediated Autophagy Substrates and Components in Cancer.

Chaperone-mediated autophagy (CMA) represents a specific way of lysosomal protein degradation and contrary to macro and microautophagy is independent of vesicles formation. The role of CMA in different physiopathological processes has been studied for several years. In cancer, alterations of the CMA principal components, Hsc70 and Lamp2A protein and mRNA levels, have been described in malignant cells. However, changes in the expression levels of these CMA components are not always associated with changes in CMA activity and their biological significance must be carefully interpreted case by case. The objective of this review is to discuss whether altering the CMA activity, CMA substrates or CMA components is accurate to avoid cancer progression. In particular, this review will discuss about the evidences in which alterations CMA components Lamp2A and Hsc70 are associated or not with changes in CMA activity in different cancer types. This analysis will help to better understand the role of CMA activity in cancer and to elucidate whether CMA can be considered as target for therapeutics. Further, it will help to define whether the attention of the investigation should be focused on Lamp2A and Hsc70 because they can have an independent role in cancer progression beyond of their participation in altered CMA activity.

Chaperone Mediated Autophagy Degrades TDP-43 Protein and Is Affected by TDP-43 Aggregation.

TAR DNA binding protein 43 kDa (TDP-43) is a ribonuclear protein regulating many aspects of RNA metabolism. Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Lobar Degeneration (FTLD) are fatal neurodegenerative diseases with the presence of TDP-43 aggregates in neuronal cells. Chaperone Mediated Autophagy (CMA) is a lysosomal degradation pathway participating in the proteostasis of several cytosolic proteins including neurodegenerative associated proteins. In addition, protein oligomers or aggregates can affect the status of CMA. In this work, we studied the relationship between CMA and the physiological and pathological forms of TDP-43. First, we found that recombinant TDP-43 was specifically degraded by rat liver's CMA+ lysosomes and that endogenous TDP-43 is localized in rat brain's CMA+ lysosomes, indicating that TDP-43 can be a CMA substrate in vivo. Next, by using a previously reported TDP-43 aggregation model, we have shown that wild-type and an aggregate-prone form of TDP-43 are detected in CMA+ lysosomes isolated from cell cultures. In addition, their protein levels increased in cells displaying CMA down-regulation, indicating that these two TDP-43 forms are CMA substrates in vitro. Finally, we observed that the aggregate-prone form of TDP-43 is able to interact with Hsc70, to co-localize with Lamp2A, and to up-regulate the levels of these molecular components of CMA. The latter was followed by an up-regulation of the CMA activity and lysosomal damage. Altogether our data shows that: (i) TDP-43 is a CMA substrate; (ii) CMA can contribute to control the turnover of physiological and pathological forms of TDP-43; and (iii) TDP-43 aggregation can affect CMA performance. Overall, this work contributes to understanding how a dysregulation between CMA and TDP-43 would participate in neuropathological mechanisms associated with TDP-43 aggregation.

Autophosphorylation of carboxy-terminal residues inhibits the activity of protein kinase CK1alpha.

CK1 constitutes a protein kinase subfamily that is involved in many important physiological processes. However, there is limited knowledge about mechanisms that regulate their activity. Isoforms CK1delta and CK1epsilon were previously shown to autophosphorylate carboxy-terminal sites, a process which effectively inhibits their catalytic activity. Mass spectrometry of CK1alpha and splice variant CK1alphaL has identified the autophosphorylation of the last four carboxyl-end serines and threonines and also for CK1alphaS, the same four residues plus threonine-327 and serine-332 of the S insert. Autophosphorylation occurs while the recombinant proteins are expressed in Escherichia coli. Mutation of four carboxy-terminal phosphorylation sites of CK1alpha to alanine demonstrates that these residues are the principal but not unique sites of autophosphorylation. Treatment of autophosphorylated CK1alpha and CK1alphaS with lambda phosphatase causes an activation of 80-100% and 300%, respectively. Similar treatment fails to stimulate the CK1alpha mutants lacking autophosphorylation sites. Incubation of dephosphorylated enzymes with ATP to allow renewed autophosphorylation causes significant inhibition of CK1alpha and CK1alphaS. The substrate for these studies was a synthetic canonical peptide for CK1 (RRKDLHDDEEDEAMS*ITA). The stimulation of activity seen upon dephosphorylation of CK1alpha and CK1alphaS was also observed using the known CK1 protein substrates DARPP-32, beta-catenin, and CK2beta, which have different CK1 recognition sequences. Autophosphorylation effects on CK1alpha activity are not due to changes in Km(app) for ATP or for peptide substrate but rather to the catalytic efficiency per pmol of enzyme. This work demonstrates that CK1alpha and its splice variants can be regulated by their autophosphorylation status.

Polycystin-2 Is Required for Starvation- and Rapamycin-Induced Atrophy in Myotubes.

Muscle atrophy involves a massive catabolism of intracellular components leading to a significant reduction in cellular and tissue volume. In this regard, autophagy, an intracellular mechanism that degrades proteins and organelles, has been implicated with muscle breakdown. Recently, it has shown that polycystin-2 (PC2), a membrane protein that belongs to the transient receptor potential (TRP) family, is required for the maintenance of cellular proteostasis, by regulating autophagy in several cell types. The role of PC2 in the control of atrophy and autophagy in skeletal muscle remains unknown. Here, we show that PC2 is required for the induction of atrophy in C2C12 myotubes caused by nutrient deprivation or rapamycin exposure. Consistently, overexpression of PC2 induces atrophy in C2C12 myotubes as indicated by decreasing of the myogenic proteins myogenin and caveolin-3. In addition, we show that inhibition of mTORC1, by starvation or rapamycin is inhibited in cells when PC2 is silenced. Importantly, even if PC2 regulates mTORC1, our results show that the regulation of atrophy by PC2 is independent of autophagy. This study provides novel evidence regarding the role of PC2 in skeletal muscle cell atrophy.

Chaperone Mediated Autophagy in the Crosstalk of Neurodegenerative Diseases and Metabolic Disorders.

Chaperone Mediated Autophagy (CMA) is a lysosomal-dependent protein degradation pathway. At least 30% of cytosolic proteins can be degraded by this process. The two major protein players of CMA are LAMP-2A and HSC70. While LAMP-2A works as a receptor for protein substrates at the lysosomal membrane, HSC70 specifically binds protein targets and takes them for CMA degradation. Because of the broad spectrum of proteins able to be degraded by CMA, this pathway has been involved in physiological and pathological processes such as lipid and carbohydrate metabolism, and neurodegenerative diseases, respectively. Both, CMA, and the mentioned processes, are affected by aging and by inadequate nutritional habits such as a high fat diet or a high carbohydrate diet. Little is known regarding about CMA, which is considered a common regulation factor that links metabolism with neurodegenerative disorders. This review summarizes what is known about CMA, focusing on its molecular mechanism, its role in protein, lipid and carbohydrate metabolism. In addition, the review will discuss how CMA could be linked to protein, lipids and carbohydrate metabolism within neurodegenerative diseases. Furthermore, it will be discussed how aging and inadequate nutritional habits can have an impact on both CMA activity and neurodegenerative disorders.

Autophagy and Its Impact on Neurodegenerative Diseases: New Roles for TDP-43 and C9orf72.

Autophagy is a catabolic mechanism where intracellular material is degraded by vesicular structures called autophagolysosomes. Autophagy is necessary to maintain the normal function of the central nervous system (CNS), avoiding the accumulation of misfolded and aggregated proteins. Consistently, impaired autophagy has been associated with the pathogenesis of various neurodegenerative diseases. The proteins TAR DNA-binding protein-43 (TDP-43), which regulates RNA processing at different levels, and chromosome 9 open reading frame 72 (C9orf72), probably involved in membrane trafficking, are crucial in the development of neurodegenerative diseases such as Amyotrophic lateral sclerosis (ALS) and Frontotemporal Lobar Degeneration (FTLD). Additionally, recent studies have identified a role for these proteins in the control of autophagy. In this manuscript, we review what is known regarding the autophagic mechanism and discuss the involvement of TDP-43 and C9orf72 in autophagy and their impact on neurodegenerative diseases.