Flavobacterium psychraquaticum sp. nov., isolated from water system of Atlantic salmon (Salmo salar) smolts cultured in Chile.

Strain LB-N7T, a novel Gram-negative, orange, translucent, gliding, rod-shaped bacterium, was isolated from water samples collected from an open system of Atlantic salmon (Salmo salar) smolts in a fish farm in Chile during a flavobacterial infection outbreak in 2015. Phylogenetic analysis based on 16S rRNA sequences (1337 bp) revealed that strain LB-N7T belongs to the genus Flavobacterium and is closely related to the type strains Flavobacterium ardleyense A2-1T (98.8 %) and Flavobacterium cucumis R2A45-3T (96.75 %). The genome size of strain LB-N7T was 2.93 Mb with a DNA G+C content 32.6 mol%. Genome comparisons grouped strain LB-N7T with Flavobacterium cheniae NJ-26T, Flavobacterium odoriferum HXWNR29T, Flavobacterium lacisediminis TH16-21T and Flavobacterium celericrescens TWA-26T. The calculated digital DNA-DNA hybridization values between strain LB-N7T and the closest related Flavobacterium strains were 23.3 % and the average nucleotide identity values ranged from 71.52 to 79.39 %. Menaquinone MK-6 was the predominant respiratory quinone, followed by MK-7. The major fatty acids were iso-C15 : 0 and anteiso-C15 : 0. The primary polar lipids detected included nine unidentified lipids, two amounts of aminopospholipid and phospholipids, and a smaller amount of aminolipid. Phenotypic, genomic, and chemotaxonomic data suggest that strain LB-N7T (=CECT 30406T=RGM 3221T) represents as a novel bacterial species, for which the name Flavobacterium psychraquaticum sp. nov. is proposed.

Identification of breadfruit (Artocarpus altilis) and South American crops introduced during early settlement of Rapa Nui (Easter Island), as revealed through starch analysis.

Starch residue analysis was carried out on stone tools recovered from the bottom layer of the Anakena site on Rapa Nui (Easter Island). These deposits have been dated to AD 1000-1300 AD and so far, represent the earliest evidence of human settlement on this island. Twenty obsidian tools were analyzed. Analysis of 46 starch grains recovered from 20 obsidian tools from the earliest dated level of the Anakena site on Rapa Nui provides direct evidence for translocation of traditional crop plants at initial stages of the colonization of this island. The analysis of starch grains was based mainly on statistical methods for species identification but was complemented by visual inspection in some cases. Our results identify taxons previously unknown to have been cultivated on the island, such as breadfruit (Artocarpus altilis), Zingiber officinale (ginger), and starch grains of the Spondias dulcis and Inocarpus fagifer tropical trees. Additionally, starch grains of Colocasia esculenta (taro) and Dioscorea sp. (yam), both common species in Pacific agriculture, were identified. Furthermore, the presence of four American taxa Ipomoea batatas (sweet potato), Canna sp. (achira), Manihot esculenta (manioc), and Xanthosoma sp., was detected. The occurrence of Canna sp., M. esculenta, and Xanthosoma sp. starch grains suggests the translocation of previously not described South American cultivars into the Pacific. The detection of I. batatas from this site in Rapa Nui constitutes the earliest record of this cultigen in the Pacific. Our study provides direct evidence for translocation of a set of traditional Polynesian and South American crop plants at the initial stages of colonization in Rapa Nui.

Mitochondrial Quality Control via Mitochondrial Unfolded Protein Response (mtUPR) in Ageing and Neurodegenerative Diseases.

Mitochondria play a key role in cellular functions, including energy production and oxidative stress regulation. For this reason, maintaining mitochondrial homeostasis and proteostasis (homeostasis of the proteome) is essential for cellular health. Therefore, there are different mitochondrial quality control mechanisms, such as mitochondrial biogenesis, mitochondrial dynamics, mitochondrial-derived vesicles (MDVs), mitophagy, or mitochondrial unfolded protein response (mtUPR). The last item is a stress response that occurs when stress is present within mitochondria and, especially, when the accumulation of unfolded and misfolded proteins in the mitochondrial matrix surpasses the folding capacity of the mitochondrion. In response to this, molecular chaperones and proteases as well as the mitochondrial antioxidant system are activated to restore mitochondrial proteostasis and cellular function. In disease contexts, mtUPR modulation holds therapeutic potential by mitigating mitochondrial dysfunction. In particular, in the case of neurodegenerative diseases, such as primary mitochondrial diseases, Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), Amyotrophic Lateral Sclerosis (ALS), or Friedreich's Ataxia (FA), there is a wealth of evidence demonstrating that the modulation of mtUPR helps to reduce neurodegeneration and its associated symptoms in various cellular and animal models. These findings underscore mtUPR's role as a promising therapeutic target in combating these devastating disorders.

Actin Polymerization Defects Induce Mitochondrial Dysfunction in Cellular Models of Nemaline Myopathies.

Nemaline myopathy (NM) is one of the most common forms of congenital myopathy and it is identified by the presence of "nemaline bodies" (rods) in muscle fibers by histopathological examination. The most common forms of NM are caused by mutations in the Actin Alpha 1 (ACTA1) and Nebulin (NEB) genes. Clinical features include hypotonia and muscle weakness. Unfortunately, there is no curative treatment and the pathogenetic mechanisms remain unclear. In this manuscript, we examined the pathophysiological alterations in NM using dermal fibroblasts derived from patients with mutations in ACTA1 and NEB genes. Patients' fibroblasts were stained with rhodamine-phalloidin to analyze the polymerization of actin filaments by fluorescence microscopy. We found that patients' fibroblasts showed incorrect actin filament polymerization compared to control fibroblasts. Actin filament polymerization defects were associated with mitochondrial dysfunction. Furthermore, we identified two mitochondrial-boosting compounds, linoleic acid (LA) and L-carnitine (LCAR), that improved the formation of actin filaments in mutant fibroblasts and corrected mitochondrial bioenergetics. Our results indicate that cellular models can be useful to study the pathophysiological mechanisms involved in NM and to find new potential therapies. Furthermore, targeting mitochondrial dysfunction with LA and LCAR can revert the pathological alterations in NM cellular models.

Variation of Plasma Damage-Associated Molecular Patterns in Patients with Advanced Solid Tumors after Standard of Care Systemic Treatment.

BACKGROUND: Immunogenic cell death (ICD) is known for releasing damage-associated molecular patterns (DAMPs) from tumor cells. We aimed to find ICD signals by assessing the variation of plasmatic DAMPs (HMGB1, S100A8) before-after standard of care (SoC) systemic treatment in patients with advanced solid tumors. METHODS: Patients scheduled to start a new line of systemic treatment were included. Plasmatic concentrations of HMGB1 and S100A8 were measured (ng/mL) before and after three months of treatment. RESULTS: Fifty-two patients were included. Forty-four patients (85%) had metastases, and 8 (15%) were treated for stage III tumors. The most frequent tumor sites were colorectal (35%) and lung (25%). Forty-two patients (81%) received this treatment in the first-line setting. Thirty-six patients (69%) were treated chemotherapy (CT) alone, ten (19%) CT plus targeted therapy, two (3.8%) carboplatin-pemetrexed-pembrolizumab, three (5.8%) pembrolizumab alone and one (1.9%) cetuximab alone. Median plasmatic concentration of S100A8 was significantly higher before than after treatment in the whole population (3.78 vs. 2.91 ng/mL; p = 0.011) and more markedly in the subgroups of patients who experienced RECIST-assessed tumor response (5.70 vs. 2.63 ng/mL; p = 0.002). Median plasmatic concentration of HMGB1was not significantly different before and after treatment (10.23 vs. 11.85 ng/mL; p = 0.382) and did not differ depending on tumor response. Median PFS was not significantly different between patients whose plasma HMBG1 concentration decreased or increased (8.0 vs. 10.6 months; p = 0.29) after treatment. Median PFS was significantly longer in those patients in whom the plasma concentration of S100A8 decreased after treatment (12 vs. 4.7 months; p < 0.001). Median OS was not significantly different between patients whose plasma HMBG1 concentration decreased or increased (13.1 vs. 14.7 months; p = 0.46) after treatment. Median OS was significantly longer in those patients in whom the plasma concentration of S100A8 decreased after treatment (16.7 vs. 9.0 months; p < 0.001). CONCLUSIONS: Signals of ICD were not observed. S100A8 behaves as an inflammatory marker with decreased concentration after treatment, mostly in RECIST-responders. PFS and OS were significantly prolonged in those patients who experienced a decrease of S100A8 compared with those patients who experienced increase of plasma S100A8 at three months.

Antioxidants Prevent Iron Accumulation and Lipid Peroxidation, but Do Not Correct Autophagy Dysfunction or Mitochondrial Bioenergetics in Cellular Models of BPAN.

Neurodegeneration with brain iron accumulation (NBIA) is a group of rare neurogenetic disorders frequently associated with iron accumulation in the basal nuclei of the brain. Among NBIA subtypes, ß-propeller protein-associated neurodegeneration (BPAN) is associated with mutations in the autophagy gene WDR45. The aim of this study was to demonstrate the autophagic defects and secondary pathological consequences in cellular models derived from two patients harboring WDR45 mutations. Both protein and mRNA expression levels of WDR45 were decreased in patient-derived fibroblasts. In addition, the increase of LC3B upon treatments with autophagy inducers or inhibitors was lower in mutant cells compared to control cells, suggesting decreased autophagosome formation and impaired autophagic flux. A transmission electron microscopy (TEM) analysis showed mitochondrial vacuolization associated with the accumulation of lipofuscin-like aggregates containing undegraded material. Autophagy dysregulation was also associated with iron accumulation and lipid peroxidation. In addition, mutant fibroblasts showed altered mitochondrial bioenergetics. Antioxidants such as pantothenate, vitamin E and α-lipoic prevented lipid peroxidation and iron accumulation. However, antioxidants were not able to correct the expression levels of WDR45, neither the autophagy defect nor cell bioenergetics. Our study demonstrated that WDR45 mutations in BPAN cellular models impaired autophagy, iron metabolism and cell bioenergetics. Antioxidants partially improved cell physiopathology; however, autophagy and cell bioenergetics remained affected.

Patient-Derived Cellular Models for Polytarget Precision Medicine in Pantothenate Kinase-Associated Neurodegeneration.

The term neurodegeneration with brain iron accumulation (NBIA) brings together a broad set of progressive and disabling neurological genetic disorders in which iron is deposited preferentially in certain areas of the brain. Among NBIA disorders, the most frequent subtype is pantothenate kinase-associated neurodegeneration (PKAN) caused by pathologic variants in the PANK2 gene codifying the enzyme pantothenate kinase 2 (PANK2). To date, there are no effective treatments to stop the progression of these diseases. This review discusses the utility of patient-derived cell models as a valuable tool for the identification of pharmacological or natural compounds for implementing polytarget precision medicine in PKAN. Recently, several studies have described that PKAN patient-derived fibroblasts present the main pathological features associated with the disease including intracellular iron overload. Interestingly, treatment of mutant cell cultures with various supplements such as pantothenate, pantethine, vitamin E, omega 3, α-lipoic acid L-carnitine or thiamine, improved all pathophysiological alterations in PKAN fibroblasts with residual expression of the PANK2 enzyme. The information provided by pharmacological screenings in patient-derived cellular models can help optimize therapeutic strategies in individual PKAN patients.

Tenacibaculum bernardetii sp. nov., isolated from Atlantic salmon (Salmo salar L.) cultured in Chile.

Strain PVT-9aT, a novel Gram-stain-negative, aerobic, non-spore-forming, motile-by-gliding and rod-shaped bacterium, was isolated from a skin lesion of Atlantic salmon (Salmo salar L.) during a tenacibaculosis outbreak that occurred in 2016 at a Chilean fish farm. Phylogenetic analysis based on 16S rRNA gene sequencing confirmed that strain PVT-9aT belonged to the genus Tenacibaculum, being related to the closest type strains Tenacibaculum haliotis KCTC 52419T (98.49 % sequence similarity), Tenacibaculum aestuariivivum JDTF-79T (97.36 %), Tenacibaculum insulae JDTF-31T (97.29 %) and Tenacibaculum ovolyticum IFO 15947T (97.15 %). The genome size of strain PVT-9aT was 2.73 Mb with a DNA G+C content 31.09 mol%. Average nucleotide identity analysis among 30 Tenacibaculum species rendered the most similar strains as follows: T. haliotis KCTC 52419T (87.91 %), T. ovolyticum IFO 15947T (82.47 %), Tenacibaculum dicentrarchi 35/09T (81.08 %), Tenacibaculum finnmarkense gv finnmarkense TNO006T (80.91 %) and T. finnmarkense gv ulcerans TNO010T (80.96 %). Menaquinone MK-6 was the predominant respiratory quinone. The predominant cell fatty acids (>10 %) were iso-C15 : 0, iso-C15 : 1 G and iso-C15 : 0 3-OH. Phenotypic, chemotaxonomic and genomic data supported the assignment of strain PVT-9aT (=DSM 115155T=RGM 3472T) as representing a novel species of Tenacibaculum, for which the name Tenacibaculum bernardetii sp. nov. is proposed.

In vitro phenotypic evidence for the utilization of iron from different sources and siderophores production in the fish pathogen Tenacibaculum dicentrarchi.

Iron uptake during infection is an essential pathogenicity factor of several bacteria, including Tenacibaculum dicentrarchi, an emerging pathogen for salmonid and red conger eel (Genypterus chilensis) farms in Chile. Iron-related protein families were recently found in eight T. dicentrarchi genomes, but biological studies have not yet confirmed functions. The investigation reported herein clearly demonstrated for the first time that T. dicentrarchi possesses different systems for iron acquisition-one involving the synthesis of siderophores and another allowing for the utilization of heme groups. Using 38 isolates of T. dicentrarchi and the type strain CECT 7612T , all strains grew in the presence of the chelating agent 2.2'-dipyridyl (from 50 to 150 µM) and produced siderophores on chrome azurol S plates. Furthermore, 37 of the 38 T. dicentrarchi isolates used at least four of the five iron sources (i.e. ammonium iron citrate, ferrous sulfate, iron chloride hexahydrate, haemoglobin and/or hemin) when added to iron-deficient media, although the cell yield was less when using hemin. Twelve isolates grew in the presence of hemin, and 10 of them used only 100 µM. Under iron-supplemented or iron-restricted conditions, whole cells of three isolates and the type strain showed at least one membrane protein induced in iron-limiting conditions (c.a. 37.9 kDa), regardless of the isolation host. All phenotypic results were confirmed by in-silico genomic T. dicentrarchi analysis. Future studies will aim to establish a relationship between iron uptake ability and virulence in T. dicentrarchi through in vivo assays.

Alpha-lipoic acid supplementation corrects pathological alterations in cellular models of pantothenate kinase-associated neurodegeneration with residual PANK2 expression levels.

BACKGROUND: Neurodegeneration with brain iron accumulation (NBIA) disorders are a group of neurodegenerative diseases that have in common the accumulation of iron in the basal nuclei of the brain which are essential components of the extrapyramidal system. Frequent symptoms are progressive spasticity, dystonia, muscle rigidity, neuropsychiatric symptoms, and retinal degeneration or optic nerve atrophy. One of the most prevalent subtypes of NBIA is Pantothenate kinase-associated neurodegeneration (PKAN). It is caused by pathogenic variants in the gene of pantothenate kinase 2 (PANK2) which encodes the enzyme responsible for the first reaction on the coenzyme A (CoA) biosynthesis pathway. Thus, deficient PANK2 activity induces CoA deficiency as well as low expression levels of 4'-phosphopantetheinyl proteins which are essential for mitochondrial metabolism. METHODS: This study is aimed at evaluating the role of alpha-lipoic acid (α-LA) in reversing the pathological alterations in fibroblasts and induced neurons derived from PKAN patients. Iron accumulation, lipid peroxidation, transcript and protein expression levels of PANK2, mitochondrial ACP (mtACP), 4''-phosphopantetheinyl and lipoylated proteins, as well as pyruvate dehydrogenase (PDH) and Complex I activity were examined. RESULTS: Treatment with α-LA was able to correct all pathological alterations in responsive mutant fibroblasts with residual PANK2 enzyme expression. However, α-LA had no effect on mutant fibroblasts with truncated/incomplete protein expression. The positive effect of α-LA in particular pathogenic variants was also confirmed in induced neurons derived from mutant fibroblasts. CONCLUSIONS: Our results suggest that α-LA treatment can increase the expression levels of PANK2 and reverse the mutant phenotype in PANK2 responsive pathogenic variants. The existence of residual enzyme expression in some affected individuals raises the possibility of treatment using high dose of α-LA.

Neurodegeneration, Mitochondria, and Antibiotics.

Neurodegenerative diseases are characterized by the progressive loss of neurons, synapses, dendrites, and myelin in the central and/or peripheral nervous system. Actual therapeutic options for patients are scarce and merely palliative. Although they affect millions of patients worldwide, the molecular mechanisms underlying these conditions remain unclear. Mitochondrial dysfunction is generally found in neurodegenerative diseases and is believed to be involved in the pathomechanisms of these disorders. Therefore, therapies aiming to improve mitochondrial function are promising approaches for neurodegeneration. Although mitochondrial-targeted treatments are limited, new research findings have unraveled the therapeutic potential of several groups of antibiotics. These drugs possess pleiotropic effects beyond their anti-microbial activity, such as anti-inflammatory or mitochondrial enhancer function. In this review, we will discuss the controversial use of antibiotics as potential therapies in neurodegenerative diseases.

Draft Genome Sequence of Tenacibaculum haliotis Strain RA3-2T, Isolated from Korean Wild Abalone (Haliotis discus hannai).

Here, we present the draft genome sequence of Tenacibaculum haliotis strain RA3-2T (i.e., KCTC 52419T and NBRC 112382T), isolated from Korean wild abalone (Haliotis discus hannai). As the only strain for this Tenacibaculum species worldwide, the information is of use for comparative genomic analyses delineating Tenacibaculum species.

Development of a PCR assay for the specific identification of the fish pathogen Tenacibaculum piscium.

Tenacibaculosis is an emerging disease that severely affects salmonid farming in Chile, producing high mortalities and causing great economic losses. This work describes a novel PCR assay for the specific detection of Tenacibaculum piscium, a species recently described and identified in tenacibaculosis outbreaks in Norway and Chile. The designed primers amplified a 678-bp fragment of the peptidase gene (peptidase M23 family) from T. piscium. This method is specific for T. piscium; no other chromosomal DNA amplification products were obtained for other Tenacibaculum species. In pure cultures, the PCR assay detected up to 500 pg of DNA, or the equivalent of 2.44 ± 0.06 × 104 CFU/ml. For seeded fish samples (i.e., gills, liver, kidney, and mucus), the sensitivity limit was 4.88 ± 0.11 × 106 CFU/g, sufficient to detect T. piscium in acute infections in fish. Notably, this sensitivity level was 100-fold lower for DNA extracted from mucus samples. As compared to other existing methodologies (e.g., gene sequencing), the PCR approach described in this work allowed for the easiest detection of T. piscium in mucus samples obtained from challenged fish, an important outcome considering that the identification of this bacterium is difficult. Our results indicate that the designed specific primers and PCR method provide a rapid and specific diagnosis of T. piscium.

mtUPR Modulation as a Therapeutic Target for Primary and Secondary Mitochondrial Diseases.

Mitochondrial dysfunction is a key pathological event in many diseases. Its role in energy production, calcium homeostasis, apoptosis regulation, and reactive oxygen species (ROS) balance render mitochondria essential for cell survival and fitness. However, there are no effective treatments for most primary and secondary mitochondrial diseases to this day. Therefore, new therapeutic approaches, such as the modulation of the mitochondrial unfolded protein response (mtUPR), are being explored. mtUPRs englobe several compensatory processes related to proteostasis and antioxidant system mechanisms. mtUPR activation, through an overcompensation for mild intracellular stress, promotes cell homeostasis and improves lifespan and disease alterations in biological models of mitochondrial dysfunction in age-related diseases, cardiopathies, metabolic disorders, and primary mitochondrial diseases. Although mtUPR activation is a promising therapeutic option for many pathological conditions, its activation could promote tumor progression in cancer patients, and its overactivation could lead to non-desired side effects, such as the increased heteroplasmy of mitochondrial DNA mutations. In this review, we present the most recent data about mtUPR modulation as a therapeutic approach, its role in diseases, and its potential negative consequences in specific pathological situations.

Vicious cycle of lipid peroxidation and iron accumulation in neurodegeneration.

Lipid peroxidation and iron accumulation are closely associated with neurodegenerative diseases, such as Alzheimer's, Parkinson's, and Huntington's diseases, or neurodegeneration with brain iron accumulation disorders. Mitochondrial dysfunction, lipofuscin accumulation, autophagy disruption, and ferroptosis have been implicated as the critical pathomechanisms of lipid peroxidation and iron accumulation in these disorders. Currently, the connection between lipid peroxidation and iron accumulation and the initial cause or consequence in neurodegeneration processes is unclear. In this review, we have compiled the known mechanisms by which lipid peroxidation triggers iron accumulation and lipofuscin formation, and the effect of iron overload on lipid peroxidation and cellular function. The vicious cycle established between both pathological alterations may lead to the development of neurodegeneration. Therefore, the investigation of these mechanisms is essential for exploring therapeutic strategies to restrict neurodegeneration. In addition, we discuss the interplay between lipid peroxidation and iron accumulation in neurodegeneration, particularly in PLA2G6-associated neurodegeneration, a rare neurodegenerative disease with autosomal recessive inheritance, which belongs to the group of neurodegeneration with brain iron accumulation disorders.

Pantothenate and L-Carnitine Supplementation Improves Pathological Alterations in Cellular Models of KAT6A Syndrome.

Mutations in several genes involved in the epigenetic regulation of gene expression have been considered risk alterations to different intellectual disability (ID) syndromes associated with features of autism spectrum disorder (ASD). Among them are the pathogenic variants of the lysine-acetyltransferase 6A (KAT6A) gene, which causes KAT6A syndrome. The KAT6A enzyme participates in a wide range of critical cellular functions, such as chromatin remodeling, gene expression, protein synthesis, cell metabolism, and replication. In this manuscript, we examined the pathophysiological alterations in fibroblasts derived from three patients harboring KAT6A mutations. We addressed survival in a stress medium, histone acetylation, protein expression patterns, and transcriptome analysis, as well as cell bioenergetics. In addition, we evaluated the therapeutic effectiveness of epigenetic modulators and mitochondrial boosting agents, such as pantothenate and L-carnitine, in correcting the mutant phenotype. Pantothenate and L-carnitine treatment increased histone acetylation and partially corrected protein and transcriptomic expression patterns in mutant KAT6A cells. Furthermore, the cell bioenergetics of mutant cells was significantly improved. Our results suggest that pantothenate and L-carnitine can significantly improve the mutant phenotype in cellular models of KAT6A syndrome.

Therapeutic approach with commercial supplements for pantothenate kinase-associated neurodegeneration with residual PANK2 expression levels.

BACKGROUND: Neurodegeneration with brain iron accumulation (NBIA) is a group of rare neurogenetic disorders frequently associated with iron accumulation in the basal nuclei of the brain characterized by progressive spasticity, dystonia, muscle rigidity, neuropsychiatric symptoms, and retinal degeneration or optic nerve atrophy. Pantothenate kinase-associated neurodegeneration (PKAN) is one of the most widespread NBIA subtypes. It is caused by mutations in the gene of pantothenate kinase 2 (PANK2) that result in dysfunction in PANK2 enzyme activity, with consequent deficiency of coenzyme A (CoA) biosynthesis, as well as low levels of essential metabolic intermediates such as 4'-phosphopantetheine, a necessary cofactor for essential cytosolic and mitochondrial proteins. METHODS: In this manuscript, we examined the therapeutic effectiveness of pantothenate, panthetine, antioxidants (vitamin E and omega 3) and mitochondrial function boosting supplements (L-carnitine and thiamine) in mutant PANK2 cells with residual expression levels. RESULTS: Commercial supplements, pantothenate, pantethine, vitamin E, omega 3, carnitine and thiamine were able to eliminate iron accumulation, increase PANK2, mtACP, and NFS1 expression levels and improve pathological alterations in mutant cells with residual PANK2 expression levels. CONCLUSION: Our results suggest that several commercial compounds are indeed able to significantly correct the mutant phenotype in cellular models of PKAN. These compounds alone or in combinations are of common use in clinical practice and may be useful for the treatment of PKAN patients with residual enzyme expression levels.

Pharmacological characterization of a novel peptide inhibitor of the Keap1-Nrf2 protein-protein interaction.

LAS200813 is a novel bicyclic lipopeptide that activates Nrf2 by binding to Keap1, thereby antagonising the Keap1-Nrf2 protein-protein interaction. In this work we report the pharmacological characterization of LAS200813 in Nrf2-dependent translational preclinical models. LAS200813 binds to Keap1 with high affinity (IC50: 0.73 nM) and is able to induce the translocation of Nrf2 to the nucleus. Furthermore, LAS200813 increases the expression of Nrf2 target genes in human bronchial epithelial cells (EC50 of 96 and 70 nM for srxn1 and nqo1, respectively). Similarly, the intratracheal administration of LAS200813 to rats increases the expression of Nrf2-dependent genes in lung tissue, an effect that lasts for a few hours. Moreover, in cells exposed to cigarette smoke, LAS200813 shows an antioxidant effect by increasing the production of glutathione and prevents cellular apoptosis. In conclusion, the results described herein demonstrate that LAS200813 is a potent non-electrophilic Nrf2-activating peptide designed to be administered by inhaled route which may be a potential therapeutic strategy for respiratory diseases driven by oxidative stress.

Activation of the Mitochondrial Unfolded Protein Response: A New Therapeutic Target?

Mitochondrial dysfunction is a key hub that is common to many diseases. Mitochondria's role in energy production, calcium homeostasis, and ROS balance makes them essential for cell survival and fitness. However, there are no effective treatments for most mitochondrial and related diseases to this day. Therefore, new therapeutic approaches, such as activation of the mitochondrial unfolded protein response (UPRmt), are being examined. UPRmt englobes several compensation processes related to proteostasis and antioxidant mechanisms. UPRmt activation, through an hormetic response, promotes cell homeostasis and improves lifespan and disease conditions in biological models of neurodegenerative diseases, cardiopathies, and mitochondrial diseases. Although UPRmt activation is a promising therapeutic option for many conditions, its overactivation could lead to non-desired side effects, such as increased heteroplasmy of mitochondrial DNA mutations or cancer progression in oncologic patients. In this review, we present the most recent UPRmt activation therapeutic strategies, UPRmt's role in diseases, and its possible negative consequences in particular pathological conditions.

Modeling Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-Like Episodes Syndrome Using Patient-Derived Induced Neurons Generated by Direct Reprogramming.

Mitochondrial diseases are a heterogeneous group of rare genetic disorders caused by mutations in nuclear or mitochondrial DNA (mtDNA). These diseases are frequently multisystemic, although mainly affect tissues that require large amounts of energy such as the brain. Mutations in mitochondrial transfer RNA (mt-tRNA) lead to defects in protein translation that may compromise some or all mtDNA-encoded proteins. Mitochondrial Encephalomyopathy, Lactic Acidosis and Stroke-like episodes (MELAS) syndrome is mainly caused by the m.3243A>G mutation in the mt-tRNALeu(UUR) (MT-TL1) gene. Owing to the lack of proper animal models, several cellular models have been developed to study the disease, providing insight in the pathophysiological mechanisms of MELAS. In this study, we show a successful direct conversion of MELAS patient-derived fibroblasts into induced neurons (iNs) for the first time, as well as an electrophysiological characterization of iNs cocultured with astrocytes. In addition, we performed bioenergetics analysis to study the consequences of m.3243A>G mutation in this neuronal model of MELAS syndrome.