Biology subjects

Vasilaki, A.

Publications and source records attributed to Vasilaki, A..

9 recordsLinked to original sources

bioRxiv2026

Consistent gut bacterial microbiota in European sea bass fed aquafeeds containing sustainable plant and invasive fish-based ingredients

The aim of this study was to evaluate the impact of two sustainable dietary protein sources on the structure and composition of the gut microbiota in European sea bass (Dicentrarchus labrax) juveniles. These protein sources were incorporated to the aquafeeds containing (a) Lupinus albus meal, treated with either exogenous enzymes (Solid state hydrolysis-SSH) or fermented with Saccharomyces cerevisiae (Solid state fermentation, SSF) and (b) Lagocephalus sceleratus meal. In the first case (a), the control aquafeed simulated a standard commercial diet, containing soybean meal whereas in the rest of the diets soybean meal was partially or totally replaced by hydrolysed or fermented Lupin meal. In the second case (b) the fish were fed Lagocephalus sceleratus unprocessed fishmeal as well as treated at different temperatures to deactivate tetrodotoxin (TTX). A control diet with 30% commercial fish meal was also fed as a reference diet. Both diets in all inclusion levels did not cause any significant gut microbiota change, suggesting their neutral role in this aspect. However, the gut bacterial communities of the fish fed with 12.5% lupin meal inclusion, had increased amino acid biosynthetic pathways suggesting a beneficial effect.

microbiology↗

bioRxiv2024

Unveiling Ageing-Associated and Caloric Restriction-Associated Changes in miRNA Expression in Rat Skeletal Muscle and the Mechanisms Mediating their Effects on Muscle Cell Function

The mechanisms underlying skeletal muscle ageing, whilst poorly understood, are thought to involve dysregulated micro (mi)RNA expression. Using young and aged rat skeletal muscle tissue, we applied high-throughput RNA sequencing to comprehensively study alterations in miRNA expression occurring with age, as well as the impact of caloric restriction (CR) on these changes. Furthermore, the function of the proteins targeted by these age- and CR-associated miRNAs was ascertained. Numerous known and novel age-associated miRNAs were identified of which CR normalised 45.5% to youthful levels. Our results suggested miRNAs upregulated with age to downregulated proteins involved in muscle tissue development and metabolism, as well as longevity pathways, such as AMPK and autophagy. Furthermore, our results found miRNAs downregulated with age to upregulate pro-inflammatory proteins, particularly those involved in innate immunity and the complement and coagulation cascades. Interestingly, CR was particularly effective at normalising miRNAs upregulated with age, rescuing their associated protein coding genes but was less effective at rescuing anti-inflammatory miRNAs downregulated with age. Lastly, the effects of a specific miRNA, miR-96-5p, identified by our analysis to be upregulated with age, were studied in culture C2C12 myoblasts. We demonstrated miR-96-5p to decrease cell viability and markers of mitochondrial biogenesis, myogenic differentiation and autophagy. Overall, our results provide useful information regarding how miRNA expression changes in skeletal muscle, as well as the consequences of these changes and how they are ameliorated by CR.

molecular biology↗

bioRxiv2024

Defining the most potent osteoinductive culture conditions for MC3T3-E1 cells reveals no implication of oxidative stress or energy metabolism

MC3T3-E1 preosteoblastic cell line is widely utilised as a reliable in vitro system to assess bone formation. However, the experimental growth conditions for these cells hugely diverge and, particularly, the osteogenic medium (OSM) composition varies in research studies. Therefore, we aimed to define the ideal culture conditions for MC3T3-E1 subclone 4 cells with regards to mineralization capacity and explore if oxidative stress or cellular metabolism processes are implicated. Cells were treated with 9 different combinations of long-lasting ascorbate (Asc) and {beta}-glycerophosphate ({beta}GP) and osteogenesis/calcification were evaluated at 3 different time-points by qPCR, Western blotting and bone nodule staining. Key molecules of oxidative and metabolic pathways were also assessed. It was found that sufficient mineral deposition was achieved only in 150g.mL-1/2mM Asc/{beta}GP combination at 21d in OSM and this was supported by Runx2, Alpl, Bglap and Col1a1 expression levels increase. NOX2 and SOD2 as well as PGC1 and Tfam were also monitored as indicators of redox and metabolic processes, respectively, where no differences were observed. Elevation in OCN protein levels and ALP activity showed that mineralisation comes as a result of these differences. This work defines the most appropriate culture conditions for MC3T3-E1 cells and could be used by other research laboratories in this field.

cell biology↗

bioRxiv2023

Lifelong dietary protein restriction accelerates skeletal muscle loss and reduces muscle fibre size by impairing proteostasis and mitochondrial homeostasis

The early life environment significantly affects the development of age-related skeletal muscle disorders. However, the long-term effects of lactational protein restriction on skeletal muscle are still poorly defined. Our study revealed that male mice nursed by dams fed a low-protein diet during lactation exhibited skeletal muscle growth restriction. This was associated with a dysregulation in the expression levels of genes related to the ribosome, mitochondria and skeletal muscle development. We reported that lifelong protein restriction accelerated loss of type-IIa muscle fibres and reduced muscle fibre size by impairing mitochondrial homeostasis and proteostasis at 18 months of age. However, feeding a normal-protein diet following lactational protein restriction prevented accelerated fibre loss and fibre size reduction in later life. These findings provide novel insight into the mechanisms by which lactational protein restriction hinders skeletal muscle growth and includes evidence that lifelong dietary protein restriction accelerated skeletal muscle loss in later life.

physiology↗

bioRxiv2023

The effect of lactational low protein diet on skeletal muscle during adulthood and ageing in male and female mouse offspring

Sarcopenia is characterised by loss of skeletal muscle mass and function associated with a reduction in muscle fibres. External factors, like exercise and diet, can also influence skeletal muscle mass and contribute to muscle fibre loss. Maternal programming refers to the effect of maternal environmental factors such as nutrition that lead to phenotypic changes in the offspring. Maternal malnutrition has been linked to a reduction in body weight and impaired development of skeletal muscle of the offspring; however, there are no studies that reported the long-term effect of maternal low protein diet on the ageing of skeletal muscles. This study aimed to examine how maternal protein deficiency during lactation affects skeletal muscle development and ageing in the offspring. Pups born from normally fed mothers were lactated by low protein fed mothers. Post-weaning, mice were either maintained on a low protein diet (LPD) or switched to normal protein diet (NPD). Pups born from normally fed mothers and maintained on NPD during lactation and afterwards were used as control. In males, the diet mainly affected the size of the myofibres without major effect on fibre number and led to a reduced grip strength of ageing mice (24 months). Female mice had a lower body and muscle weight at weaning but caught up with control mice at 3 months. During ageing, muscle weight, myofibre number and survival rate of female pups were significantly affected. These findings highlight longitudinal animal research for nutritional programming and the importance of sexual dimorphism in response to challenges. HighlightsO_LIPostnatal low protein diet significantly decreases the survival rate of female but not male mice. C_LIO_LIDuring ageing, female mice fed a low protein diet during lactation have lower muscle weight. C_LIO_LIDuring ageing, female mice fed a low protein diet postnatally maintain their myofibre number. C_LIO_LIMale mice fed a low protein diet postnatally have lower body weight and muscle weight throughout their lifespan. C_LIO_LILow protein diet affects myofibres size of TA muscle of male but not female mice at 3 months of age however this effect is lost during ageing. C_LI

physiology↗

bioRxiv2022

Postnatal protein intake as a determinant of skeletal muscle structure and function in mice - a pilot study

Sarcopenia is characterised by an age-related decrease in the number of muscle fibres and additional weakening of the remaining fibres, resulting in a reduction in muscle mass and function. Many studies associate poor maternal nutrition during gestation and/or lactation with altered skeletal muscle homeostasis in the offspring and the development of sarcopenia. The aim of this study was to determine whether the musculoskeletal physiology in offspring born to mouse dams fed a low-protein diet during pregnancy was altered and whether any physiological changes could be modulated by the nutritional protein content in early postnatal stages. Thy1-YFP female mice were fed ad libitum on either a normal (20%) or a low-protein (5%) diet. Newborn pups were cross-fostered to different lactating dams (maintained on 20% or 5% diet) to generate 3 groups analysed at weaning (21 days): Normal-to-Normal (NN), Normal-to-Low (NL) and Low-to-Normal (LN). Further offspring were maintained ad libitum on the same diet as during lactation until 12 weeks of age creating another 3 groups (NNN, NLL, LNN). Mice on a low protein diet postnatally (NL, NLL) exhibited a significant reduction in body and muscle weight persisting up to 12 weeks, unlike mice on a low protein diet only prenatally (LN, LNN). Muscle fibre size was reduced in mice from the NL but not LN group, showing recovery at 12 weeks of age. Muscle force was reduced in NLL mice, concomitant with changes in the NMJ site and changes in atrophy-related and myosin genes. In addition, CT scans of mouse tibiae at 12 weeks of age revealed changes in bone mass and morphology, resulting in a higher bone mass in the NLL group than the control NNN group. Finally, changes in the expression of miR-133 in the muscle of NLL mice suggest a regulatory role for this microRNA in muscle development in response to postnatal diet changes. Overall, this data shows that a low maternal protein diet and early postnatal life low-protein intake in mice can impact skeletal muscle physiology and function in early life while postnatal low protein diet favors bone integrity in adulthood.

physiology↗

bioRxiv2022

Deletion of Sod1 in motor neurons exacerbates age-related changes in axons and NMJs associated with premature muscle atrophy in aging mice

Whole body knock out of Cu, Zn superoxide dismutase1 (Sod1KO) results in accelerated, age-related loss of muscle mass and function associated with a breakdown of neuromuscular junctions (NMJ) similar to sarcopenia. In order to determine whether altered redox in motor neurons is integral to this phenotype, an inducible neuron specific deletion of Sod1 (i-mnSod1KO) was compared with wild type (WT) mice of different ages (adult, mid-age and old) and whole body Sod1KO mice. Nerve oxidative damage, motor neuron numbers and structural changes to neurons and NMJ were examined. Deletion of neuronal Sod1 (induced by tamoxifen injection at 6 months of age) caused the exaggerated, age-associated loss of muscle mass and force generation previously reported. No effect of age or lack of neuronal Sod1 was seen on oxidation in the sciatic nerve assessed by electron paramagnetic resonance of the in vivo spin probe 1-hydroxy-3-carboxy-2,2,5,5 tetramethylpyrrolidine (CPH), analysis of protein 3-nitrotyrosines or carbonyl content. i-mnSod1KO mice showed increased numbers of denervated NMJs, a reduced number of large axons and increased number of small axons compared with age-matched old WT mice. A large proportion of the remaining innervated NMJs in i-mnSod1KO mice also displayed a much simpler structure than that seen in WT mice. Thus, while Sod1KO mice recapitulate substantially the neuromuscular phenotypes of old WT mice, deletion of Sod1 specifically in neurons induces exaggerated loss of muscle mass and force only in old (24-29 month) mice indicating that significant muscle declines require the accumulation of age-related changes such that a threshold is reached past which maintenance of structure and function is not possible. Significance statementSarcopenia is the age-related loss of muscle mass and function. It is a significant contributor to frailty and to increased falls in the elderly. While multifactorial, changes in redox status have been shown to have significant influence over neuromuscular aging, recent work suggests that changes in motor neurons may be the driving factor in muscle atrophy. The current study confirmed that a specific lack of Sod1 in the motor neuron causes significant alteration in axonal architecture and the neuromuscular junctions which can drive reduced muscle mass and function. Pinpointing early changes in motor neurons may provide therapeutic targets critical for maintaining muscle in the elderly.

physiology↗

bioRxiv2021

Small-RNA sequencing reveals altered skeletal muscle microRNAs and snoRNAs signatures in weanling male offspring from mouse dams fed a low protein diet during lactation

Nutrition plays a key role in pre- and postnatal growth of the musculoskeletal system. Maternal diet during gestation and lactation affects the development of skeletal muscles in the offspring and determines muscle health in later life, however, the molecular mechanisms that govern these effects are largely unknown. In this study, we aim to describe the association between maternal low protein diet-induced changes in offspring skeletal muscle and the differential expression (DE) of small non-coding RNAs (sncRNAs). We used a mouse model of maternal protein restriction to characterise the impact of early-life undernutrition on skeletal muscle morphology in male offspring at weaning. Mouse dams were fed either a normal (N, 20%) or a low protein (L, 8%) diet during gestation and newborn pups were cross-fostered to N or L lactating dams, resulting in the generation of NN, NL and LN offspring groups. Total body and tibialis anterior (TA) weights were decreased in NL males but not different in the LN group, as compared to NN, although neonates from low protein fed dams were smaller at birth than those born to dams fed a normal protein. However, histological evaluation of TA muscle revealed reduced muscle fibre size in both groups at the end of lactation. Small RNA-seq analysis demonstrated DE of multiple classes of sncRNAs, including miRs, snoRNAs and snRNAs. Bioinformatic analyses of miRs-15a, -34a, -122 and -199a, in combination with known myomiRs, confirmed their implication in key muscle-specific biological processes and cellular functions and suggest a promising set of miRs in muscle physiology studies. To our knowledge, this is the first comprehensive report for the DE of sncRNAs in nutrition-associated programming of skeletal muscle development, highlighting the need for further research.

molecular biology↗

bioRxiv2020

Low protein intake compromises the recovery of lactation-induced bone loss in female mouse dams without affecting skeletal muscles.

ABSTRACTLactation-induced bone loss occurs due to high calcium requirements for fetal growth but skeletal recovery is normally achieved promptly post-weaning. Dietary protein is vital for fetus and mother but the effects of protein undernutrition on the maternal skeleton and skeletal muscles is largely unknown. We used mouse dams fed with normal (N, 20%) or low (L, 8%) protein diet during gestation and lactation and maintained on the same diets (NN, LL) or switched from low to normal (LN) during a 28d skeletal restoration period post lactation. Skeletal muscle morphology and neuromuscular junction integrity was not different between any of the groups. However, dams fed the low protein diet showed extensive bone loss by the end of lactation, followed by full skeletal recovery in NN dams, partial recovery in LN and poor bone recovery in LL dams. Primary osteoblasts from low protein diet fed mice showed decreased in vitro bone formation and decreased osteogenic marker gene expression; promoter methylation analysis by pyrosequencing showed no differences in Bmpr1a, Ptch1, Sirt1, Osx and Igf1r osteoregulators, while miR-26a, -34a and -125b expression was found altered in low protein fed mice. Therefore, normal protein diet is indispensable for maternal musculoskeletal health during the reproductive period.Competing Interest StatementThe authors have declared no competing interest.View Full Text

physiology↗