Protein Damage Research Articles

O-038 Impact of maternal aging on the DNA repair landscape in mouse oocytes

Abstract Study question How does maternal aging impact DNA damage accumulation and DNA repair capacity in mammalian oocytes? Summary answer Age-related changes in DNA repair compartments and chromatin organisation drive DNA damage accumulation in aged oocytes, ultimately contributing to the decline in DNA repair capacity. What is known already Oocyte loss occurs progressively from birth and accelerates as women approach their mid-30s, posing a significant challenge to female reproductive health. Recent studies have highlighted the role of the DNA repair response in driving ovarian ageing and oocyte loss. Aged oocytes accumulate elevated levels of DNA damage. Unless repaired, persistent DNA damage activates DNA repair checkpoints, causing the elimination of defective oocytes. Although we know DNA double-strand breaks (DSBs) in oocytes increase with maternal age, surprisingly, little is known about why this damage is not repaired efficiently. Study design, size, duration Oocytes were isolated from ovaries of 8 weeks or 68-86-week-old CD1 mice, which correspond to reproductively young and old females respectively. Over 600 and 1000 oocytes from aged any young females were used to analyse DNA damage levels, DNA repair effciency, DNA repair compartments and for other live assays. Participants/materials, setting, methods DNA damage was induced in CD1 oocytes from young and aged mice using neocarzinostatin. Levels of DNA damage and DNA repair proteins were quantified using immunofluoresnce confocal/STED microscopy. High-resolution light sheet microscopy was used to perform live imaging of dynamics of DNA damage foci and chromosome segregation during meiosis. Main results and the role of chance Our work demonstrates that aged oocytes have a lower DNA repair capacity and reduced mobility of DNA damage sites compared to young oocytes. We further show that incomplete DNA repair results in defective chromosome integrity and partitioning, thereby compromising oocyte quality. To investigate the causes of the age-related decline in DNA repair, we systematically studied the localization and abundance of several DNA repair proteins in oocytes from young and aged mice. We found that DNA repair proteins localized in spatially distinct DNA repair compartments in oocyte nuclei, that form during the late stages of oocyte growth, accompanied by changes in the activity of DNA repair pathways. Several DNA repair proteins, their corresponding compartments, and their response to DNA damage were altered in aged oocytes. Lastly, we demonstrate that age-related cohesin loss increases DNA damage levels and reduces DNA repair capacity. We hypothesize that cohesin dissociation with maternal ageing may make chromosomes prone to accumulate DNA damage without proper DNA repair. Thus, age-related changes in DNA repair compartments and chromatin organisation drive DNA damage accumulation in aged oocytes, ultimately contributing to the decline in reproductive potential. Limitations, reasons for caution Neocarzinostatin, a radiomimetic drug used to induce DNA DSBs in mouse oocytes in vitro, may not fully represent sources of DNA damage during aging. The CD1 mouse model and ages were selected to recapitulate equivalent advanced maternal age in women. Further investigation is needed to confirm these findings in humans. Wider implications of the findings Overall, we propose that altered DNA repair machinery and cohesin loss contribute to persistent DNA damage and reduced DNA repair capacity in aged oocytes, which can cause chromosome defects and fragmentation, and eventually trigger oocyte death, thereby accelerating the loss of female fertility. Trial registration number Not Applicable

Biosynthesis, Antibacterial and Antifungal Activities of Ag Nanoparticles Prepared Using Piper nigrum Fruit Extract

Nanomaterials are promising alternatives to antibiotics with the potential to handle the menace of emerging multidrug resistance in pathogenic microbes. We report a simple biosynthetic approach to prepare Ag nanoparticles (NPs) with strong antibacterial and antifungal actions by using Piper nigrum fruit extract as a bioreducing agent. The biosynthesized material was characterized by SEM, AFM, TEM, HRTEM, XRD and UV–Visible absorption spectroscopy. SEM, AFM and TEM analyses provided evidence that the average diameter of the Ag NPs was 18[Formula: see text]nm, while XRD and HRTEM confirmed the FCC structure of Ag NPs. The biosynthesized Ag NPs demonstrated extremely strong antibacterial activity against Bacillus oceanisediminis and Escherichia coli, and showed extremely strong antifungal action against Schizosaccharomyces pombe, inhibiting their growth at very low concentrations of 3[Formula: see text][Formula: see text]g/mL, 4[Formula: see text][Formula: see text]g/mL and 3[Formula: see text][Formula: see text]g/mL, respectively. The molecular origin of their antibacterial and antifungal activity was studied using various molecular and biochemical assays. The results of these assays revealed a major role for reactive oxygen species (ROS) in the antifungal and antibacterial actions of the biosynthesized Ag NPs. Furthermore, morphological changes in cells and cell wall damage upon Ag NP treatment were observed by scanning electron microscopy. In addition, significant enhancement in protein leakage and fragmentation of DNA was also observed upon treatment of S. pombe, B. oceanisediminis and E. coli with Ag NPs. In conclusion, the observed extremely strong antibacterial and antifungal activities of biosynthesized Ag NPs are due to the oxidative stress triggered by ROS, causing cell wall damage and subsequent protein leakage and DNA fragmentation.

Identification of Early Protein Damage-Associated Molecular Pattern (DAMPs) Candidates from Cardiac Cells Subjected to an In Vitro Myocardial Ischemic Injury

Damage-associated molecular patterns (DAMPs) are intracellular molecules that are released from cells that undergo injury. Protein-DAMPs are abundant biomolecules that could potentially be a novel biomarker for pathology. Myocardial ischemia injury is a causative process for ischemic heart disease, which is now the leading cause of global deaths. Early diagnosis is necessary to save patient lives, so the discovery of new early cardiac biomarkers is crucial. Here, we examined the protein-DAMPs expression in ischemic buffer collected from adult ventricular myocytes cells subjected to various timepoints of simulated ischemia (sI). Adult ventricular myocytes cells (AC-16) were subjected to sublethal simulated ischemia (sI) by treatment with ischemic buffer for 5, 10, 20, and 30 minutes (I5, I10, I20, and I30, respectively). After simulated ischemia was achieved, the ischemic buffer was collected and determined for proteins profiling by Shotgun proteomics approach. Cell viability was reduced in a time dependent manner in ischemia. Targeted proteomics reveals 21 proteins found to highly increase in early ischemic injury and can still be detected until 30 minutes of ischemia. Lactotransferrin (LTF) was determined to be the protein with the greatest impact, exhibiting both fast and sustained release throughout the whole study time. The present study identified the protein damage associated molecular pattern (DAMPs) released specifically from ischemia-induced cardiomyocytes injury, which could potentially be candidates to be early biomarkers for myocardial ischemic injury. Further studies should be focused on in vivo validation of potential protein markers that could be used in practical clinical applications.

Unveiling the crucial role of oxidative stress on steroid hormone receptors

ABSTRACT Oxidative stress is widely recognized as a major contributor to male infertility. Reactive oxygen species (ROS) can interact with various cellular components, causing irreversible damage to the male reproductive system. This damage results in several adverse effects, including impaired sperm motility, abnormal spermatogenesis, sperm deoxyribonucleic acid (DNA) damage, and altered steroidogenesis. Furthermore, oxidative damage to steroid hormone receptors contributes to their functional impairment. These factors, individually or collectively, lead to infertility or subfertility in men. ROS can damage proteins, lipids, and nucleic acids, with oxidative DNA damage potentially causing mutations, particularly in germ cells, as studies have shown. Such damage is also observed in steroid hormones and their receptors in men. Understanding the relationship between oxidative stress and its impact on genes is crucial for the accurate diagnosis, recognition, and treatment of male infertility. High-dose antioxidant supplementation, a beacon of hope, may eliminate, scavenge, or neutralize ROS, thereby mitigating ROS-induced genomic damage and oxidative harm to steroid hormones. Consequently, this approach may be considered the primary remedy against oxidative stress-induced male infertility.

Novel triphenylamine-pyrene-based AIEgens: Specific detection and imaging of H2O2 in aqueous solution and cells

H2O2 plays a key regulatory role as a bioendogenous reactive oxygen species in cells and organisms. However, excessive production or accumulation of H2O2 during mitochondrial oxidative stress may lead to oxidative damage of cellular proteins and trigger rheumatic diseases, cancers, and a variety of neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. In addition, H2O2 is a very useful chemical widely employed in the textile and chemical industries, and its excessive emission not only pollutes the environment but also jeopardizes human health. Therefore, the sensitive and specific detection and removal of H2O2 is important for early diagnosis of diseases, treatment prognosis and environmental pollution monitoring. We have designed two novel triphenylamine-based AIEgens MOTPP and MOTPP-B, which each have a high solid-state fluorescence quantum yield and excellent aggregation-induced emission properties. MOTPP-B has high selectivity and anti-interference ability toward H2O2, a wide pH tolerance range, a sensing process that is complete in under 40 min, and a low detection limit of 120.77 nM. It has been successfully applied for the detection of low concentrations of H2O2 in the environment and to dual-channel imaging of low concentrations of exogenous H2O2 in living cells.

Placental Protein 13 and Syncytiotrophoblast Basement Membrane Ultrastructures in Preeclampsia.

Background and Objectives: Preeclampsia has been linked to an inflammatory response that may be brought on by endothelial cell dysfunction. This paper investigates the pathomechanism of syncytiotrophoblast basement membrane (STBM) damage and Placental Protein 13 (PP13) release, which may have a role in systemic endothelial dysfunction in preeclampsia. Materials and Methods: This comparative cross-sectional study involves 54 preeclampsia patients (27 early-onset preeclampsia and 27 late-onset preeclampsia) and 27 pregnant women with normal blood pressure. An enzyme-linked immunosorbent assay was performed to evaluate maternal blood levels of PP13. Following birth, a portion of the placenta was collected for transmission electron microscope (TEM) and immunohistochemical (IHC) analysis. The data were analyzed using STATA version 15. Results: PP13 expression in the placental syncytiotrophoblast was significantly lower in the early-onset preeclampsia, compared to late-onset preeclampsia and normotensive pregnancy, group (p < 0.001). In contrast, serum PP13 levels were found to be the highest in the early-onset preeclampsia group, although no significant difference were found in mean maternal serum levels of PP13 between the three groups. The decreased PP13 expression in placental syncytiotrophoblast can be attributed to the greater extent of damage in the STBM in early-onset preeclampsia that leads to the release of a larger amount of PP13 into maternal circulation. The hypothesis aligns with the TEM analysis results. Preeclamptic pregnancies showed placental syncytiotrophoblast aponeurosis, whereas normotensive pregnancies did not. Placental lesions and STBM shedding were found to be more pronounced in early-onset preeclampsia compared to late-onset preeclampsia. Conclusions: PP13 and STBM damage may play a role in systemic endothelial dysfunction in preeclampsia.

Exposure to O3 and NO2 on the interfacial chemistry of the pulmonary surfactant and the mechanism of lung oxidative damage

Exposure to ozone (O3) and nitrogen dioxide (NO2) are related to pulmonary dysfunctions and various lung diseases, but the underlying biochemical mechanisms remain uncertain. Herein, the effect of inhalable oxidizing gas pollutants on the pulmonary surfactant (PS, extracted from porcine lungs), a mixture of active lipids and proteins that plays an important role in maintaining normal respiratory mechanics, is investigated in terms of the interfacial chemistry using in-vitro experiments; and the oxidative stress induced by oxidizing gases in the simulated lung fluid (SLF) supplemented with the PS is explored. The results showed that O3 and NO2 individually increased the surface tension of the PS and reduced its foaming ability; this was accompanied by the surface pressure-area isotherms of the PS monolayers shifting toward lower molecular areas, with O3 exhibiting more severe effects than NO2. Moreover, both O3 and NO2 produced reactive oxygen species (ROS) resulting in lipid peroxidation and protein damage to the PS. The formation of superoxide radicals (O2•–) was correlated with the decomposition of O3 and the reactions of O3 and NO2 with antioxidants in the SLF. These radicals, in the presence of antioxidants, led to the formation of hydrogen peroxide and hydroxyl radicals (•OH). Additionally, the direct oxidation of unsaturated lipids by O3 and NO2 further caused an increase in the ROS content. This change in the ROS chemistry and increased •OH production tentatively explain how inhalable oxidizing gases lead to oxidative stress and adverse health effects. In summary, our results indicated that inhaled O3 and NO2 exposure can significantly alter the interfacial properties of the PS, oxidize its active ingredients, and induce ROS formation in the SLF. The results of this study provide a basis for the elucidation of the potential hazards of inhaled oxidizing gas pollutants in the human respiratory system.

In situ stoichiometry amounts of p62 and poly-ubiquitin exceed the increase of alpha-synuclein during degeneration of catecholamine cells induced by autophagy inhibition in vitro.

Neurodegenerative disorders are typically featured by the occurrence of neuronal inclusions. In the case of Parkinson's disease (PD) these correspond to Lewy bodies (LBs), which are routinely defined as proteinaceous inclusions composed of alpha-synuclein (alpha-syn). In turn, alpha-syn is considered to be the key protein in producing PD and fostering its progression. Recent studies challenged such a concept and emphasized the occurrence of other proteins such as p62 and poly-ubiquitin (Poly-ub) in the composition of LBs, which are also composed of large amounts of tubulo-vesicular structures. All these components, which accumulate within the cytosol of affected neurons in PD, may be the consequence of a dysfunction of major clearing pathways. In fact, autophagy-related systems are constantly impaired in inherited PD and genetic models of PD. The present study was designed to validate whether a pharmacological inhibition of autophagy within catecholamine cells produces cell damage and accumulation of specific proteins and tubulo-vesicular structures. The stoichiometry counts of single proteins, which accumulate within catecholamine neurons was carried out along with the area of tubulo-vesicular structures. In these experimental conditions p62 and Poly-ub accumulation exceeded at large the amounts of alpha-syn. In those areas where Poly-ub and p62 were highly expressed, tubulo-vesicular structures were highly represented compared with surrounding cytosol. The present study confirms new vistas about LBs composition and lends substance to the scenario that autophagy inhibition rather than a single protein dysfunction as key determinant of PD.

Autophagy markers LC3 and p62 in aging lumbar motor neurons

Autophagy is a ubiquitous process through which damaged cytoplasmic structures are recycled and degraded within cells. Aging can affect autophagy regulation in different steps leading to the accumulation of damaged organelles and proteins, which can contribute to cell dysfunction and death. Motor neuron (MN) loss and sarcopenia are prominent features of neuromuscular aging. Previous studies on phrenic MNs showed increased levels of the autophagy proteins LC3 and p62 in 24 month compared to 6 month old mice, consistent with the onset of diaphragm muscle sarcopenia. In the present study, we hypothesized that aging leads to increased expression of the autophagy markers LC3 and p62 in single lumbar MNs. Expression of LC3 and p62 in lumbar MNs (spinal levels L1-L6) was assessed using immunofluorescence and confocal imaging of male and female mice at 6, 18 and 24 months of age, reflecting 100 %, 90 % and 75 % survival, respectively. A mixed linear model with animal as a random effect was used to compare relative LC3 and p62 expression in choline acetyl transferase-positive MNs across age groups. Expression of LC3 and p62 decreased in the white matter of the lumbar spinal cord with aging, with ~29 % decrease in LC3 and ~ 7 % decrease in p62 expression at 24 months of age compared to 6 months of age. There was no change in LC3 or p62 expression in the gray matter with age. LC3 expression in MNs relative to white matter increased significantly with age, with 150 % increase at 24 months of age compared to 6 months of age. Similarly, p62 expression in MNs relative to white matter increased significantly with age, with ~14 % increase at 24 months of age compared to 6 months of age. No effect of sex or MN pool was observed in LC3 and p62 expression in MNs. Overall, these data suggest autophagy impairment during elongation (increased LC3) and degradation (increased p62) phases with aging in lumbar MNs.

The Interactive Effects of the Anti-Sea Lice Pesticide Azamethiphos and Temperature on Oxidative Damage and Antioxidant Responses in the Oyster Ostrea chilensis.

Azamethiphos is used in the salmon industry to treat sea lice and is subsequently discharged into the sea, which may affect non-target species (NTS). A rise in seawater temperature could enhance the sensitivity of NTS. Thus, in the present investigation, the combined effects of azamethiphos (0 µg L-1, 15 µg L-1 and 100 µg L-1) and temperature (12 °C and 15 °C) was assessed over time (7 days) in the gonads and gills of the oyster Ostrea chilensis, assessing its oxidative damage (lipid peroxidation and protein carbonyls) and total antioxidant capacity. Our results indicated that in gonads and gills, lipid peroxidation levels increased over time during exposure to both pesticide concentrations. Protein carbonyl levels in gills increased significantly in all experimental treatments; however, in gonads, only pesticide concentration and exposure time effected a significant increase in protein damage. In both, gill and gonad temperature did not influence oxidative damage levels. Total antioxidant capacity in gonads was influenced only by temperature treatment, whereas in the gills, neither temperature nor azamethiphos concentration influenced defensive responses. In conclusion, our results indicated the time of pesticide exposure (both concentrations) had a greater influence than temperature on the cellular damage in this oyster.

SLC10A1 rs2296651 variant (S267F mutation) predicts biochemical traits, hepatitis B virus infection susceptibility and the risk of gallstone disease.

Sodium taurocholate co-transporting polypeptide (NTCP), a bile acid transporter, plays a crucial role in regulating bile acid levels and influencing the risk of HBV infection. Genetic variations in the SLC10A1 gene, which encodes NTCP, affect these functions. However, the impact of SLC10A1 gene variants on the metabolic and biochemical traits remained unclear. We aimed to investigate the association of SLC10A1 gene variants with the clinical and biochemical parameters, and the risk of different HBV infection statuses and gallstone disease in the Taiwanese population. Genotyping data from 117,679 Taiwan Biobank participants were analyzed using the Axiom genome-wide CHB arrays. Regional-plot association analysis demonstrated genome-wide significant association between the SLC10A1 rs2296651 genotypes and lipid profile, gamma glutamyl transferase (γGT) level and anti-HBc-positivity. Genotype-phenotype association analyses revealed significantly lower total cholesterol, low-density lipoprotein (LDL) cholesterol and uric acid levels, a higher γGT level and a higher gallstone incidence in rare rs2296651-A allele carrier. Participants with the rs2296651 AA-genotype exhibited significantly lower rates of anti-HBc-positivity and HBsAg-positivity. Compared to those with the GG-genotype, individuals with non-GG-genotypes had reduced risks for various HBV infection statuses: the AA-genotype showed substantially lower risks, while the GA-genotype demonstrated modestly lower risks. Predictive tools also suggested that the rs2296651 variant potentially induced protein damage and pathogenic effects. In conclusion, our data revealed pleiotropic effects of the SLC10A1 rs2296651 genotypes on the levels of biochemical traits and the risk of HBV infection and gallstone disease. This confirms SLC10A1's versatility and implicates its genotypes in predicting both biochemical traits and disease susceptibility.

Effects of ultrashort wave on neuronal damage and heat shock protein 70 expression after cerebral ischemia-reperfusion injury in rats

BackgroundUltrashort wave (USW) therapy has been reported to alleviate cerebral ischemia/reperfusion (IR) injury, however the underlying mechanisms remain elusive. The aim of this study was to observe the effect of non-thermal USW therapy on neuronal damage and expression of heat shock protein 70 (HSP70) after cerebral IR in rats. MethodsFocal ischemia-reperfusion (IR) was induced in Sprague–Dawley rats by middle cerebral artery occlusion/reperfusion (MCAO/R). The Ninety-two rats (both male and female) were screened using the Zea-Longa 5 grade evaluation. Included rats were then randomly divided into blank, sham, model 1-day, model 3-day, model 7-day, USW 1-day, USW 3-day, or USW 7-day groups. All rats in the model groups received sham USW treatment, while rats in the USW groups received USW treatment, for 1, 3, or 7 days. We assessed the National Institutes of Health Stroke Scale, brain infarction volumes, ultrastructural damage scores using electron microscopy, and HSP70 expression by western blotting between the different groups. ResultsUSW treatment reduced the National Institutes of Health Stroke Scale, infarction volume, and ultrastructural neuronal damage, and increased expression of HSP70, in the hippocampal CA1 region. ConclusionsNon-thermal USW therapy may improve neurological function, decrease infarction volume, and reduce neuronal damage by increasing HSP70 expression following cerebral IR injury.

Uncovering the impact of alcohol on internal organs and reproductive health: Exploring TLR4/NF-kB and CYP2E1/ROS/Nrf2 pathways.

This review delves into the detrimental impact of alcohol consumption on internal organs and reproductive health, elucidating the underlying mechanisms involving the Toll-like receptor 4 (TLR4)/Nuclear factor kappa light chain enhancer of activated B cells (NF-kB) pathway and the Cytochrome P450 2E1 (CYP2E1)/reactive oxygen species (ROS)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathways. The TLR4/NF-kB pathway, crucial for inflammatory and immune responses, triggers the production of pro-inflammatory agents and type-1 interferon, disrupting the balance between inflammatory and antioxidant responses when tissues are chronically exposed to alcohol. Alcohol-induced dysbiosis in gut microbes heightens gut wall permeability to pathogen-associated molecular patterns (PAMPs), leading to liver cell infection and subsequent inflammation. Concurrently, CYP2E1-mediated alcohol metabolism generates ROS, causing oxidative stress and damaging cells, lipids, proteins, and deoxyribonucleic acid (DNA). To counteract this inflammatory imbalance, Nrf2 regulates gene expression, inhibiting inflammatory progression and promoting antioxidant responses. Excessive alcohol intake results in elevated liver enzymes (ADH, CYP2E1, and catalase), ROS, NADH, acetaldehyde, and acetate, leading to damage in vital organs such as the heart, brain, and lungs. Moreover, alcohol negatively affects reproductive health by inhibiting the hypothalamic-pituitary-gonadal axis, causing infertility in both men and women. These findings underscore the profound health concerns associated with alcohol-induced damage, emphasizing the need for public awareness regarding the intricate interplay between immune responses and the multi-organ impacts of alcohol consumption.

Altered autophagic flux in GNE mutant cells of Indian origin: Potential drug target for GNE myopathy

Autophagy phenomenon in the cell maintains proteostasis balance by eliminating damaged organelles and protein aggregates. Imbalance in autophagic flux may cause accumulation of protein aggregates in various neurodegenerative disorders. Regulation of autophagy by either calcium or chaperone play a key role in the removal of protein aggregates from the cell. The neuromuscular rare genetic disorder, GNE Myopathy, is characterized by accumulation of rimmed vacuoles having protein aggregates of β-amyloid and tau that may result from altered autophagic flux. In the present study, the autophagic flux was deciphered in HEK cell-based model for GNE Myopathy harbouring GNE mutations of Indian origin. The refolding activity of HSP70 chaperone was found to be reduced in GNE mutant cells compared to wild type controls. The autophagic markers LC3II/I ratio was altered with increased number of autophagosome formation in GNE mutant cells compared to wild type cells. The cytosolic calcium levels were also increased in GNE mutant cells of Indian origin. Interestingly, treatment of GNE mutant cells with HSP70 activator, BGP-15, restored the expression and refolding activity of HSP70 along with autophagosome formation. Treatment with calcium chelator, BAPTA-AM restored the cytoplasmic calcium levels and autophagosome formation but not LC3II/I ratio significantly. Our study provides insights towards GNE mutation specific response for autophagy regulation and opens up a therapeutic advancement area in calcium signalling and HSP70 function for GNE related Myopathy.

The new kids on the block: RNA-binding proteins regulate autophagy in disease.

Mammalian autophagy is a highly regulated and conserved cellular homeostatic process. Its existence allows the degradation of self-components to mediate cell survival in different stress conditions. Autophagy is involved in the regulation of cellular metabolic needs, protecting the cell or tissue from starvation through the degradation and recycling of cytoplasmic materials and organelles to basic molecular building blocks. It also plays a critical role in eliminating damaged or harmful proteins, organelles, and intracellular pathogens. Thus, a deterioration of the process may result in pathological conditions, such as aging-associated disorders and cancer. Understanding the crucial role of autophagy in maintaining the normal physiological function of cells, tissue, or organs has led to copious and expansive research regarding the regulation of this process. So far, most of the research has revolved around transcriptional and post-translational regulation. Here, we discuss the regulation of autophagy-related (ATG) mRNA transcripts by RNA-binding proteins (RBPs). This analysis focuses on how RBPs modulate autophagy in disease. A deeper understanding of the involvement of RBPs in autophagy can facilitate further research and treatment of a variety of human diseases.

Coevolution of longevity and female germline maintenance.

An often-overlooked aspect of life-history optimization is the allocation of resources to protect the germline and secure safe transmission of genetic information. While failure to do so renders significant fitness consequences in future generations, germline maintenance comes with substantial costs. Thus, germline allocation should trade off with other life-history decisions and be optimized in accordance with an organism's reproductive schedule. Here, we tested this hypothesis by studying germline maintenance in lines of seed beetle, selected for early (E) or late (L) reproduction for 350 and 240 generations, respectively. Female animals provide maintenance and screening of male gametes in their reproductive tract and oocytes. Here, we reveal the ability of young and aged E- and L-females to provide this form of germline maintenance by mating them to males with ejaculates with artificially elevated levels of protein and DNA damage. We find that germline maintenance in E-females peaks at young age and then declines, while the opposite is true for L-females, in accordance with the age of reproduction in the respective regime. These findings identify the central role of allocation to secure germline integrity in life-history evolution and highlight how females can play a crucial role in mitigating the effects of male germline decisions on mutation rate and offspring quality.

Influence of increasing acclimation temperature on growth, digestion, antioxidant capacity, liver transcriptome and intestinal microflora of Ussruri whitefish Coregonus ussuriensis Berg

For effective restoration, conservation of Ussruri whitefish Coregonus ussuriensis Berg and coping with global climate change, effects of environmental temperature on Ussruri whitefish urgently need to be explored. In current study, the effects of different acclimation temperatures on the growth, digestive physiology, antioxidant ability, liver transcriptional responses and intestinal microflora patterns of Ussruri whitefish were investigated. Ussruri whitefish (15.20 g ± 1.23 g) were reared for 42 days under different acclimation temperatures, i.e., 10, 13, 16, 19, 22 and 25 °C, respectively. Result first determined 28 °C as the semi-lethal temperature in order to design the temperature gradient test. Highest main gain rate (MGR) and specific growth rate (SGR) were observed in fish group having acclimation temperature of 19 °C. Significantly decrease (P < 0.05) in triglyceride (TG) content appeared at 19 °C as compared to the 10 °C and 13 °C temperature groups. 19 °C notablely increased protease activities of stomach and intestine and intestinal lipase and amylase activities. 19 °C group obtained the highest activities of chloramphnicol acetyltransferase (CAT) and total antioxidant capacity (T-AOC) and higher activities of superoxide dismutase (SOD). The intestinal microflora composition was most conducive to maintaining overall intestinal health when the temperature was 19 °C, compared to 10 °C and 25 °C. Ussruri whitefish exposed to 10 °C and 25 °C possessed the lower Lactobacillus abundance compared to exposure to 19 °C. Temperature down to 10 °C or up to 25 °C, respectively, triggered cold stress and heat stress, which leading to impairment in intestinal digestion, liver antioxidant capacity and intestinal microflora structure. Liver transcriptome response to 10 °C, 19 °C and 25 °C revealed that Ussruri whitefish might require the initiation of endoplasmic reticulum stress to correct protein damage from cold-temperature and high-temperature stress, and it was speculated that DNAJB11 could be regarded as a biomarker of cold stress response.Based on the quadratic regression analysis of MGR and SGR against temperature, the optimal acclamation temperature were, respectively, 18.0 °C and 18.1 °C. Our findings provide valuable theoretical insights for an in-depth understanding of temperature acclimation mechanisms and laid the foundation for conservation and development of Ussruri whitefish germplasm resources.

Tyrosinase deficiency impairs social novelty preference in mice.

Tyrosinase is a rate-limiting enzyme for the biosynthesis of melanin pigment in peripheral tissues, such as skin and the retina. We recently reported the expression and enzymatic activity of tyrosinase as well as its protective effects against oxidative stress-induced protein damage in the mouse brain. The functional role of tyrosinase in the central nervous system, however, remains largely unknown. In the present study, we investigated the involvement of tyrosinase in social behavior in mice. Pigmented C57BL/10JMsHir (B10) and tyrosinase-deficient albino B10.C- Tyr c /Hir (B10-c) mice were subjected to the three-chamber sociability test to assess sociability and social novelty preference. In addition, we measured the mRNA expression of genes involved in catecholamine metabolism in the hippocampus by real-time quantitative PCR analysis. The results obtained showed that tyrosinase deficiency impaired social novelty preference, but not sociability in mice. We also found that the hippocampal expression of genes involved in catecholamine metabolism, such as monoamine oxidase A and catechol-O-methyltransferase , were significantly decreased in tyrosinase-deficient B10-c mice. These results suggest that tyrosinase activity is functionally involved in the phenotypic expression of social behavior, particularly social novelty preference, in mice. The present study will advance our understanding of the functional role of tyrosinase in the central nervous system.

Location also matters: The oxidative response of the intertidal purple mussel Perumytilus purpuratus during tidal cycle

For sessile intertidal organisms, periods of low tide impose both cellular and physiological challenges that can determine bathymetric distribution. To understand how intertidal location influences the cellular response of the bivalve Perumytilus purpuratus during the tidal cycle (immersion-emersion-immersion), specimens from the upper intertidal (UI) and lower intertidal (LI) of bathymetric distribution were sampled every 2 h over a 10-h period during a summer tidal cycle. Parallelly, organisms from the UI and LI were reciprocally transplanted and sampled throughout the same tidal cycle. Levels of oxidative damage (lipid peroxidation and protein carbonyls) as well as total antioxidant capacity and total carotenoids were evaluated as cellular responses to variations in environmental conditions throughout the tidal cycle. The results indicate that both the location in the intertidal zone (UI/LI), the level of aerial exposure, and the interaction of both factors are determinants of oxidative levels and total antioxidant capacity of P. purpuratus. Although oxidative damage levels are triggered during the low tide period (aerial exposure), it is the UI specimens that induce higher levels of lipid peroxidation compared to those from the LI, which is consistent with the elevated levels of total antioxidant capacity. On the other hand, organisms from the LI transplanted to the UI increase the levels of lipid peroxidation but not the levels of protein carbonyls, a situation that is also reflected in higher levels of antioxidant response and total carotenoids than those from the UI transplanted to the LI. The bathymetric distribution of P. purpuratus in the intertidal zone implies differentiated responses between organisms of the lower and upper limits, influenced by their life history. A high phenotypic plasticity allows this mussel to adjust its metabolism to respond to abrupt changes in the surrounding environmental conditions.

Cardioprotective effect of the anti-ageing protein Klotho on ischemic heart disease

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): ISCIII, Ministerio de Universidades, Education and Research Council of Madrid, Biomedicine Network Comunidad de Madrid Background Cardiovascular diseases are the leading cause of death and disability worldwide. Among them, ischemic heart disease, due to myocardial infarction (MI) remains the first cause of cardiovascular death. The anti-ageing protein Klotho is mainly expressed in membrane at renal level. However, Klotho also has a soluble form with different pleiotropic functions that are still undetermined, including a possible cardioprotective role that is currently the target of several studies. Purpose Firstly, we evaluated circulating Klotho levels related to cardiac damage in a cohort of 146 patients after ST-elevation myocardial infarction (STEMI) and in an experimental post-myocardial infarction (PMI) model. Secondly, we investigated soluble Klotho supplementation as a potential novel therapeutic strategy for the prevention of cardiac dysfunction, deleterious remodeling, cardiomyocyte calcium (Ca2+) mishandling and arrhythmias in PMI mice. Methods Study with human samples: we analysed Klotho and NT-proBNP plasma levels in STEMIpatients with preserved renal function. Experimental study: C57BL6 mice subjected to PMI by ligation of the left anterior descending coronary artery were treated with vehicle solution or recombinant Klotho (10 mg/Kg/day) for 15 days after MI. Cardiac function was studied through non-invasive methods including electrocardiogram (ECG) and cardiac magnetic resonance imaging (CMRI). Intracellular Ca2+ handling was analysed using confocal microscopy in isolated ventricular cardiomyocytes. Cardiac remodeling was studied through histological and biomolecular analysis of several markers of cardiac damage and target proteins involved in Ca2+ handling. Results Plasma Klotho levels decrease rapidly after MI in both STEMI patients and PMI mice. Additionally, MI patients in the lowest Klotho tertile showed significantly elevated NT-proBNP levels. Klotho treatment decreased the infarct area in PMI mice accompanied by a decrease in both cardiac hypertrophy and fibrosis. Moreover, reduction in ejection fraction and MI-related ECG alterations were reduced in PMI mice treated with Klotho, including increased QRS, JT, QTc intervals and occurrence of premature ventricular contractions. Klotho also prevented systolic Ca2+ release and cell shortening disturbances in cardiomyocytes from PMI mice without Klotho. Increased diastolic Ca2+ leak was prevented in mice treated with Klotho via CaMKII-dependent pathway by avoiding its phosphorylation and the RyR2 phosphorylation at CaMKII site. Conclusions Klotho supplementation protect against MI by avoiding deleterious cardiac remodeling and ameliorating one of the main complications of MI such as arrhythmias. Thus, recombinant Klotho prevents the intracardiomyocyte Ca2+ mishandling after MI. Our translational findings support the importance of Klotho as a novel biomarker of ventricular damage just after MI and as a novel therapeutic strategy for prevention cardiac events associated to ischemic heart disease.