Biology subjects

Luna, L.

Publications and source records attributed to Luna, L..

4 recordsLinked to original sources

bioRxiv2024

Functional Impact of Nth-like DNA glycosylase on Mitochondrial Dynamics

NTH-like DNA glycosylase (NTHL1), a key enzyme in the base excision repair (BER) pathway, has long been considered essential for maintaining both nuclear and mitochondrial genome integrity. In this study, we integrate in vitro biochemical assays, in-cellulo molecular biology experiments, and bioinformatic analyses to investigate the impact of NTHL1 loss on mitochondrial DNA (mtDNA) stability and function. Our findings challenge the conventional view by showing that the loss of NTHL1 confers a positive phenotype. Although NTHL1 deletion in human cells results in a significant accumulation of mtDNA lesions, it is unexpectedly accompanied by a substantial increase in mtDNA copy number (CN), which correlates with elevated oxidative phosphorylation (OXPHOS) protein levels and enhanced mitochondrial respiratory capacity. Additionally, NTHL1-knockout cells exhibit larger mitochondria and increased levels of the mitochondrial biogenesis regulator peroxisome proliferator-activated receptor {gamma} coactivator 1 (PGC1) and the membrane fusion protein Dynamin-like GTPase OPA1. These changes suggest an adaptive response to stress or altered cellular demands, aimed at enhancing mitochondrial function and capacity. Consequently, NTHL1-knockout cells showed resistance to 1-methyl-4-phenylpyridinium (MPP+)-induced mitochondrial stress along with increased phosphorylation of eIF2. Together, this suggests that the loss of NTHL1 may enhance cellular resilience to oxidative stress by activating protective integrated stress response and mitohormesis pathways thereby contributing to cellular survival under adverse conditions. Collectively, our findings position NTHL1 as a key player in mtDNA stability and mitochondrial function, linking its DNA repair activity to the integrated stress response. Its loss triggers a shift from canonical oxidative phosphorylation to stress-adaptive pathways, ultimately enhancing cellular resistance against oxidative stress through the activation of the mitochondrial hormetic response.

cell biology↗

bioRxiv2022

First detection of Leptospira santarosai in the reproductive track of a boar: a potential threat to swine production and public health

BackgroundLeptospirosis causes significant economic losses and is an occupational risk in the swine industry, especially in developing tropical regions where social and geoclimatic conditions are favorable for the transmission of this disease. Although vaccination can reduce infection risk, efficacy is diminished if local genetic and antigenic variants of the pathogen are not accounted for in the vaccine. Identifying and characterizing strains that circulate in different populations is therefore critical for public health mitigation practices. Methodology/Principal findingsOur study was conducted on a rural breeding farm in Ecuador, where we identified, for the first time, Leptospira santarosai in the kidneys, testicles, and ejaculate of a vaccinated boar. L. santarosai was detected with a PCR assay that targets lipL32, and identified by target MLST gene sequencing using an Oxford Nanopore MinION sequencer. Conclusions/SignificanceAs L. santarosai is pathogenic in other livestock species and humans, our finding highlights the need to evaluate the prevalence and epidemiological significance of this pathogen in pigs. In addition, further studies are needed to identify and characterize local serovars that may impact diagnosis and vaccination programs to better control leptospirosis in pigs and spillover into the human population. Author summaryLeptospirosis poses a significant threat to human and animal health. In tropical countries, leptospirosis is very common, and responsible of economic losses in the livestock industry. In peridomestic and rural farms, the spillover of leptospira to humans is particularly likely as humans live and work in close proximity to animals. Although animal vaccination can reduce risk of infection, efficacy is diminished when local variants are not included in the vaccine. This report describes, for the first time, the presence of Leptospira santarosai in the reproductive tract of a vaccinated domestic boar from a rural farm in Ecuador. We detected the pathogen in its semen and urine, and despite no tissue damage, was observed in the kidneys, testes or epididymis. The farm veterinarian reported reproductive problems in sows inseminated with the semen from this boar. Our results highlight the importance of recognizing locally circulating serovars and species so that they can be included in vaccines to prevent infection and disease. Effective control of leptospirosis in livestock not only reduces economic losses for breeders, but also reduces the risk of infection and disease in humans.

microbiology↗

bioRxiv2021

NEIL1 and NEIL2 DNA glycosylases regulate anxiety and learning in a cooperative manner

Oxidative DNA damage in the brain has been implicated in neurodegeneration and cognitive decline. DNA glycosylases initiate base excision repair (BER), the main pathway for oxidative DNA base lesion repair. NEIL1 and NEIL3 DNA glycosylases alter cognition in mice, the role of NEIL2 remains unclear. Here, we investigate the impact of NEIL2 and its potential overlap with NEIL1 on behavior in single and double knock-out mouse models. Neil1-/-Neil2-/- mice displayed hyperactivity, reduced anxiety and improved learning. Hippocampal oxidative DNA base lesion levels were comparable between genotypes, no mutator phenotype was found. Impaired canonical repair was thus not the cause of altered behavior. Electrophysiology indicated reduced stratum oriens afferents in the hippocampal CA1 region in Neil1-/-Neil2-/-. Within CA1, NEIL1 and NEIL2 jointly regulated transcription in genes relevant for synaptic function. Thus, we postulate a cooperative function of NEIL1 and NEIL2 in genome regulation beyond canonical BER modulating memory formation and anxiety.

molecular biology↗

bioRxiv2020

Genomic diversity, population structure and accessory genome analysis of Pasteurella multocida: New Insights into host adaptation and disease specialization

Pasteurella multocida is a multi-host pathogen that infects a wide spectrum of domestic and wild animals including humans. Despite its impact on health and economics, P. multocida is considered an enigmatic pathogen and the genetic basis of its pathogenicity and host adaptation still remains unclear. Here we present a detailed genomic framework based on 336 whole-genome sequences of P. multocida isolates from different animal species and countries. Our data provide genomic support of the existence of two very divergent phylogroups (PmI and PmII), which present a barrier to homologous recombination suggesting genetic isolation. Additionally, a torCAD operon, which reduces TMAO (trimethylamine N-oxide) to produce energy during bacterial anaerobic respiration, is present only in PmI and can act as a hypothetical driver of niche segregation between phylogroups. The PmI phylogroup harbors strains that infect a wider range of hosts than PmII, and shows a highly diverse phylogeny and accessory genome. We identified nine clonal lineages for PmI, seven of which are associated with specific hosts or diseases and contain distinct accessory gene pools that can confer ecologically relevant phenotypes. We found differential presence of a trehalose metabolism operon in the bovine lineage associated with pneumonic pasteurellosis; while, citrate, L-arabinose, L-fucose, and D-allose operons are only present in avian lineages. These findings suggest that alternative metabolic pathways may facilitate the establishment of P. multocida during host colonization in the early stages of infection promoting the adaptation of P. multocida lineages to certain hosts.

microbiology↗