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A hypercaloric fatty diet predisposes an individual to metabolic syndrome and cardiovascular complications. Sirtuin1 (SIRT1) belongs to the class III histone deacetylase family and sustains anabolism, mitochondrial biogenesis, and fat distribution. Epididymal white adipose tissue (eWAT) is involved in inflammation, whilst interscapular brown adipose tissue (iBAT) drives metabolism in obese rodents. Melatonin, a pineal indoleamine, acting as a SIRT1 modulator, may alleviate cardiometabolic damage. In the present study, we morphologically characterized the heart, eWAT, and iBAT in male heterozygous SIRT1+/− mice (HET mice) on a high-fat diet (60%E lard) versus a standard rodent diet (8.5% E fat) and drinking melatonin (10 mg/kg) for 16 weeks. Wild-type (WT) male C57Bl6/J mice were similarly fed for comparison. Cardiomyocyte fibrosis and endoplasmic reticulum (ER) stress response worsened in HET mice on a high-fat diet vs. other groups. Lipid peroxidation, ER, and mitochondrial stress were assessed by 4 hydroxy-2-nonenal (4HNE), glucose-regulated protein78 (GRP78), CCAA/enhancer-binding protein homologous protein (CHOP), heat shock protein 60 (HSP60), and mitofusin2 immunostainings. Ultrastructural analysis indicated the prevalence of atypical inter-myofibrillar mitochondria with short, misaligned cristae in HET mice on a lard diet despite melatonin supplementation. Abnormal eWAT adipocytes, crown-like inflammatory structures, tumor necrosis factor alpha (TNFα), and iBAT whitening characterized HET mice on a hypercaloric fatty diet and were maintained after melatonin supply. All these data suggest that melatonin's mechanism of action is strictly linked to full SIRT1 expression, which is required for the exhibition of effective antioxidant and anti-inflammatory properties. [ABSTRACT FROM AUTHOR]

Serbian spruce (Picea omorika (Pancic) Purk.) is tertiary relict and endemic species with restricted and fragmented natural range in Serbia and Bosnia and Herzegovina, mainly around the mid-course of the Drina river. Serbian spruce has been on The International Union for Conservation of Nature's Red List (IUCN) of Threatened Species since 1998. In the beginning it was marked as a vulnerable species and since 2010 as an endangered species. Serbian spruce is a tree species which has a wide ecological aspect in relation to the basic ecological factors, and the forest associations that were the subject of this research are among the most valuable forest associations in the region. The research described in this paper conducted with an aim to define the type of forests that contain Serbian spruce as an edifier in the area of mountain Radava in the Republic of Srpska (Bosnia and Herzegovina) in order to genetically preserve this rare and endangered tree species from the Balkans. Based on the research of ecological factors of habitats and the definition of production stand characteristics, the production type of forest was singled out - Forest type of European beech, silver fir, Norway spruce and Serbian spruce (Piceo omorikae-Abietetum [5]) on a series of soils on limestone. [ABSTRACT FROM AUTHOR]

Background: The effect of insulin on the endocrine pancreas has been the subject of extensive study, but quantitative morphometric investigations of the exocrine pancreas are scarce. This study was therefore undertaken to investigate the effect of acute and chronic insulin administration (two doses, 0.4 IU and 4 IU) on the morphology of rat pancreas acini.Materials and Methods: Semi-fine sections stained with methylene blue and basic fuchsine or haematoxylin and eosin-stained 5-micrometer thick paraffin sections were used for fractal and stereological analysis of exocrine acini. Acute insulin treatment, independent of applied doses increased fractal dimension in line with decreased lacunarity of pancreas acini. Chronic low dose insulin decreased fractal dimension and increased lacunarity of pancreas acini, but a high dose had the opposite effect. The volume densities (Vv) of cytoplasm, granules and nucleus are affected differently: acute low dose and high chronic dose significantly decreased granules Vv, and in line increased cytoplasmic Vv, whereas other examined structures showed slight changes without statistical significance.Results: The results obtained from this investigation indicate that insulin treatment induced structural remodelling of the exocrine pancreas suggesting a substantial role of insulin in its functioning.Conclusions: Additionally, we showed that fine architectural changes in acini could be detected by fractal analysis, suggesting this method as an alternative or addition to routine stereology. [ABSTRACT FROM AUTHOR]

Cardiomyocytes are particularly sensitive to oxidative damage due to the link between mitochondria and sarcoplasmic reticulum necessary for calcium flux and contraction. Melatonin, important indoleamine secreted by the pineal gland during darkness, also has important cardioprotective properties. We designed the present study to define morphological and ultrastructural changes in cardiomyocytes and mainly in mitochondria of an animal model of obesity (ob/ob mice), when treated orally or not with melatonin at 100 mg/kg/day for 8 weeks (from 5 up to 13 week of life). We observed that ob/ob mice mitochondria in sub-sarcolemmal and inter-myofibrillar compartments are often devoid of cristae with an abnormally large size, which are called mega-mitochondria. Moreover, in ob/ob mice the hypertrophic cardiomyocytes expressed high level of 4hydroxy-2-nonenal (4HNE), a marker of lipid peroxidation but scarce degree of mitofusin2, indicative of mitochondrial sufferance. Melatonin oral supplementation in ob/ob mice restores mitochondrial cristae, enhances mitofusin2 expression and minimizes 4HNE and p62/SQSTM1, an index of aberrant autophagic flux. At pericardial fat level, adipose tissue depot strictly associated with myocardium infarction, melatonin reduces adipocyte hypertrophy and inversely regulates 4HNE and adiponectin expressions. In summary, melatonin might represent a safe dietary adjuvant to hamper cardiac mitochondria remodeling and the hypoxic status that occur in pre-diabetic obese mice at 13 weeks of life. [ABSTRACT FROM AUTHOR]

Thyroid hormone (TH) receptors (TRs α and β) are homologous ligand-dependent transcription factors (TFs). While the TRs display distinct actions in development, metabolic regulation and other processes, comparisons of TRα and TRβ dependent gene regulation mostly reveal similar mechanisms of action and few TR subtype specific genes. Here, we show that TRα predominates in multipotent human adipose derived stem cells (hADSC) whereas TRβ is expressed at lower levels and is upregulated during hADSC differentiation. The TRs display several unusual properties in parental hADSC. First, TRs display predominantly cytoplasmic intracellular distribution and major TRα variants TRα1 and TRα2 colocalize with mitochondria. Second, knockdown experiments reveal that endogenous TRs influence hADSC cell morphology and expression of hundreds of genes in the absence of hormone, but do not respond to exogenous TH. Third, TRα and TRβ affect hADSC in completely distinct ways; TRα regulates cell cycle associated processes while TRβ may repress aspects of differentiation. TRα splice variant specific knockdown reveals that TRα1 and TRα2 both contribute to TRα-dependent gene expression in a gene specific manner. We propose that TRs work in a non-canonical and hormone independent manner in hADSC and that prominent subtype-specific activities emerge in the context of these unusual actions. [ABSTRACT FROM AUTHOR]

Developmental dysfunction in embryos, such as a lethal level of fragmentation, is assumed to be mitochondrial in origin. This study investigated the molecular basis of mitochondrial impairment in embryo fragmentation. Transcription patterns of factors that determine mitochondrial functionality: (i) components of the oxidative phosphorylation (OXPHOS) – complex I, cytochrome b, complex IV and ATP synthase; (ii) mitochondrial membrane potential (MMP); (iii) mitochondrial DNA (mtDNA) content and (iv) proteins involved in mitochondrial dynamics, mitofusin 1 (Mfn1) and dynamin related protein 1 (Drp1) were examined in six-cells Day 3 non-fragmented (control), low-fragmented (LF) and high-fragmented (HF) human embryos. Gene expression of mitochondria-encoded components of complex I and IV, cytochrome b and mtDNA were increased in HF embryos compared with control and LF embryos. In LF embryos, expression of these molecules was decreased compared with control and HF embryos. Both classes of fragmented embryos had decreased MMP compared with control. LF embryos had increased gene expression of Mfn1 accompanied by decreased expression of Drp1, while HF embryos had decreased Mfn1 expression but increased Drp1 expression. The study revealed that each improper transcriptional (in)activation of mitochondria-encoded components of the OXPHOS during early in vitro embryo development is associated with a decrease in MMP and with embryo fragmentation. The results also showed the importance of mitochondrial dynamics in fragmentation, at least in the extent of this process. [ABSTRACT FROM AUTHOR]

Background: Obesity is a common risk factor for non-alcoholic fatty liver disease (NAFLD). Currently, there are no specific treatments against NAFLD. Thus, examining any molecule with potential benefits against this condition emerged melatonin as a molecule that influences metabolic dysfunctions. The aim of this study was to determine whether melatonin would function against NAFDL, studying morphological, ultrastuctural and metabolic markers that characterize the liver of ob/ob mice. Methods: Lean and ob/ob mice were supplemented with melatonin in the drinking water for 8 weeks. Histology and stereology were performed to assess hepatic steatosis and glycogen deposition. Ultrastructural features of mitochondria, endoplasmic reticulum (ER) and their juxtapositions were evaluated in livers of all experimental groups. Furthermore, hepatic distribution and expression of markers of ER and mitochondria (calnexin, ATP sintase β, GRP78 and CHOP) and metabolic dysfunction (RPB4, β-catenin) and cellular longevity (SIRT1) were analyzed. Results: Melatonin significantly reduced glycemia, identified also by a decrease of hepatic RBP4 expression, reversed macrosteatosis in microsteatosis at the hepatic pericentral zone, enlarged ER-mitochondrial distance and ameliorated the morphology and organization of these organelles in ob/ob mouse liver. Furthermore, in ob/ob mice, calnexin and ATP synthase β were partially restored, GRP78 and CHOP decreased in periportal and midzonal hepatocytes and β-catenin expression was, in part, restored in peripheral membranes of hepatocytes. Melatonin supplementation to ob/ob mice improves hepatic morphological, ultrastructural and metabolic damage that occurs as a result of NAFLD. Conclusions: Melatonin may be a potential adjuvant treatment to limit NAFLD and its progression into irreversible complications. [ABSTRACT FROM AUTHOR]

This study examined the molecular basis of energy-related regulatory mechanisms underlying metabolic recruitment of skeletal muscle during cold acclimation and possible involvement of the L-arginine/nitric oxide-producing pathway. Rats exposed to cold (4±1°C) for periods of 1, 3, 7, 12, 21 and 45 days were divided into three groups: untreated, L-arginine treated and Nɷ-nitro-Larginine methyl ester (L-NAME) treated. Compared with controls (22±1°C), there was an initial increase in the protein level of 5'- AMP-activated protein kinase a (day 1), followed by an increase in peroxisome proliferator-activated receptor-? coactivator-1a (PGC-1ɑ) and peroxisome proliferator-activated receptors (PPARs): PPARa and PPARɣ from day 1 and PPARd from day 7 of cold acclimation. Activation of the PGC-1ɑ/PPAR transcription program was accompanied by increased protein expression of the key metabolic enzymes in ß-oxidation, the tricarboxylic acid cycle and oxidative phosphorylation, with the exceptions in complex I (no changes) and ATP synthase (decreased at day 1). Cold did not affect hexokinase and GAPDH protein levels, but increased lactate dehydrogenase activity compared with controls (1-45 days). L-arginine sustained, accelerated and/or intensified cold-induced molecular remodeling throughout cold acclimation. L-NAME exerted phase-dependent effects: similar to L-arginine in early cold acclimation and opposite after prolonged cold exposure (from day 21). It seems that upregulation of the PGC-1ɑ/PPAR transcription program early during cold acclimation triggers the molecular recruitment of skeletal muscle underlying the shift to more oxidative metabolism during prolonged cold acclimation. Our results suggest that nitric oxide has a role in maintaining the skeletal muscle oxidative phenotype in late cold acclimation but question its role early in cold acclimation. [ABSTRACT FROM AUTHOR]

Background/Aims: Study elucidates and compares the mitochondrial bioenergetic-related molecular basis of sevoflurane and propofol cardioprotection during aortic valve replacement surgery due to aortic valve stenosis. Methods: Twenty-two patients were prospectively randomized in two groups regarding the anesthetic regime: sevoflurane and propofol. Hemodynamic parameters, biomarkers of cardiac injury and brain natriuretic peptide (BNP) were measured preoperatively and postoperatively. In tissue samples, taken from the interventricular septum, key mitochondrial molecules were determined by Western blot, real time PCR, as well as confocal microscopy and immunohisto- and immunocyto-chemical analysis. Results: The protein levels of cytochrome c oxidase and ATP synthase were higher in sevoflurane than in propofol group. Nevertheless, cytochrome c protein content was higher in propofol than sevoflurane receiving patients. Propofol group also showed higher protein level of connexin 43 (Cx43) than sevoflurane group. Besides, immunogold analysis showed its mitochondrial localization. The mRNA level of mtDNA and uncoupling protein (UCP2) were higher in propofol than sevoflurane patients, as well. On the other hand, there were no significant differences between groups in hemodynamic assessment, intensive care unit length of stay, troponin I and BNP level. Conclusions: Our data indicate that sevoflurane and propofol lead to cardiac protection via different mitochondrially related molecular mechanisms. It appears that sevoflurane acts regulating cytochrome c oxidase and ATP synthase, while the effects of propofol occur through regulation of cytochrome c, Cx43, mtDNA transcription and UCP2. [ABSTRACT FROM AUTHOR]

The increased ambient temperature affects the function of hypothalamic-pituitary-adrenal (HPA) axis. Since the correlation among vasopressin (VP), adrenocorticotropic hormone (ACTH) and corticosterone (CORT) responses to various stressors have been long recognized, the aim of this study was to reveal the aforementioned hormones production and morphology of the pituitary gland after exposure to acute heat. Rats were exposed to high ambient temperature (38°C) for 20 or 60 minutes. The circulating hormones were determined by an ELISA test or chemiluminescence's method. The results obtained show the elevation in ACTH and CORT secretion depending on the duration of heat exposure. The VP concentration increased only after prolonged exposure to heat (60 min). The pituitary morphology was examined by routine and fluorescent immunohistochemistry as well as electron microscopy. Observed changes in the anterior and posterior pituitary well corresponded to circulating hormones, regarding the volume density of ACTH-immunopositive cells, percentage of ACTH immunopositive area v. total area and number of VP-immunopositive containing varicose fibers per total area. Acute heat exposure also induced changes in shapes of ACTH-immunopositive cells. Cells appeared stellate with numerous slender cytoplasmic processes and degranulated, which is the most obvious after 20 min. In addition, immunopositivity of endothelial and anterior pituitary cells for VP suggests its influence on ACTH secretion. [ABSTRACT FROM AUTHOR]

Despite peroxisomes being important partners of mitochondria by carrying out fatty acid oxidation in brown adipocytes, no clear evidence concerning peroxisome origin and way(s) of biogenesis exists. Herein we used methimazole-induced hypothyroidism for 7, 15, and 21 days to study peroxisomal remodeling and origin in rat brown adipocytes. We found that peroxisomes originated via both canonic, and de novo pathways. Each pathway operates in euthyroid control and over the course of hypothyroidism, in a time-dependent manner. Hypothyroidism increased the peroxisomal number by 1.8-, 3.6- and 5.8-fold on days 7, 15, and 21. Peroxisomal presence, their distribution, and their degree of maturation were heterogeneous in brown adipocytes in a Harlequin-like manner, reflecting differences in their origin. The canonic pathway, through numerous dumbbell-like and "pearls on strings" structures, supported by high levels of Pex11β and Drp1, prevailed on day 7. The de novo pathway of peroxisomal biogenesis started on day 15 and became dominant by day 21. The transition of peroxisomal biogenesis from canonic to the de novo pathway was driven by increased levels of Pex19, PMP70, Pex5S, and Pex26 and characterized by numerous tubular structures. Furthermore, specific peroxisomal origin from mitochondria, regardless of thyroid status, indicates their mutual regulation in rat brown adipocytes. [ABSTRACT FROM AUTHOR]

Sirtuin 1 (SIRT1), a conserved member of the family of the silencing information regulator 2 enzymes called sirtuins, is a NAD+ dependent deacetylase, and a key mediator of lifespan, and metabolism [1]. Melatonin, the pineal indolamine, is a potent SIRT1 activator which alleviates the cardiometabolic syndrome in genetically obese leptin-deficient mice [2]. Here, to best characterize its role in dietary obesity, we analysed morphological changes induced in whole body SIRT1 heterozygous mice (HET) on a high fat diet (58.4% E from fat-lard TD03584-Envigo) vs mice on standard maintenance rodent diet (8.4% E from fat). Male wildtype C57BL6/J mice (WT) were placed on above regimens for comparison. HET and WT mice received a standard diet (STD) or a high fat (HFD) diet for 16 weeks and melatonin, in drinking water at 10 mg/kg/day. Cardiac reaction to the hypercaloric lard diet was characterized analysing inter-myofibrillary mitochondria, fibrosis, lipid peroxidation, inflammation, and endoplasmic reticulum stress. Remarkably, round mitochondria with abnormal cristae, fibrosis and inflammation were exacerbated in HET HFD despite melatonin. Oxidative damage, endoplasmic reticulum stress and inflammation have been validated by strong 4HNE, GRP78, CHOP and NLRP3 immunostaining. Unfortunately, melatonin failed to improve cardiac alterations in HET HFD group. These data highlight the strict interdependence between melatonin and SIRT1 in the treatment of cardiac complications in obesity. [ABSTRACT FROM AUTHOR]

The effects of insulin on the bioenergetic and thermogenic capacity of brown adipocyte mitochondria were investigated by focusing on key mitochondrial proteins. Two-month-old male Wistar rats were treated acutely or chronically with a low or high dose of insulin. Acute low insulin dose increased expression of all electron transport chain complexes and complex IV activity, whereas high dose increased complex II expression. Chronic low insulin dose decreased complex I and cyt c expression while increasing complex II and IV expression and complex IV activity. Chronic high insulin dose decreased complex II, III, cyt c, and increased complex IV expression. Uncoupling protein (UCP) 1 expression was decreased after acute high insulin but increased following chronic insulin treatment. ATP synthase expression was increased after acute and decreased after chronic insulin treatment. Only a high dose of insulin increased ATP synthase activity in acute and decreased it in chronic treatment. ATPase inhibitory factor protein expression was increased in all treated groups. Confocal microscopy showed that key mitochondrial proteins colocalize differently in different mitochondria within a single brown adipocyte, indicating mitochondrial mosaicism. These results suggest that insulin modulates the bioenergetic and thermogenic capacity of rat brown adipocytes in vivo by modulating mitochondrial mosaicism. [ABSTRACT FROM AUTHOR]

We previously demonstrated that hypothyroidism increases peroxisomal biogenesis in rat brown adipose tissue (BAT). We also showed heterogeneity in peroxisomal origin and their unique structural association with mitochondria and/or lipid bodies to carry out β-oxidation, contributing thus to BAT thermogenesis. Distinctive heterogeneity creates structural compartmentalization within peroxisomal population, raising the question of whether it is followed by their functional compartmentalization regarding localization/colocalization of two main acyl-CoA oxidase (ACOX) isoforms, ACOX1 and ACOX3. ACOX is the first and rate-limiting enzyme of peroxisomal β-oxidation, and, to date, their protein expression patterns in BAT have not been fully defined. Therefore, we used methimazole-induced hypothyroidism to study ACOX1 and ACOX3 protein expression and their tissue immunolocalization. Additionally, we analysed their specific peroxisomal localization and colocalization in parallel with peroxisomal structural compartmentalization in brown adipocytes. Hypothyroidism caused a linear increase in ACOX1 expression, while a temporary decrease in ACOX3 levels is only recovered to the control level at day 21. Peroxisomal ACOX1 and ACOX3 localization and colocalization patterns entirely mirrored heterogeneous peroxisomal biogenesis pathways and structural compartmentalization, e.g. associations with mitochondria and/or lipid bodies. Hence, different ACOX isoforms localization/colocalization creates distinct functional heterogeneity of peroxisomes and drives their functional compartmentalization in rat brown adipocytes., Competing Interests: We have no competing interests., (© 2023 The Authors.)

Zinc (in the form of Zn 2+ ) is necessary for male fertility. Both Zn 2+ quantity and its localisation have been detected in seminal plasma and ejaculated spermatozoa, suggesting its active uptake via zinc import transporters (ZIPs). Immunofluorescence was used to characterise the expression and localisation of three distinct types of ZIP transporters in ejaculated spermatozoa of normo- and asthenozoospermic sperm samples. ZIP6, ZIP10 and ZIP14 showed heterogeneous sperm cell expression and different compartmental distribution. In both types of sperm samples, ZIP6 and ZIP14 were predominantly localised in the sperm head, while ZIP10 was found along the sperm tail. Compartmental localisation of ZIPs in asthenozoospermia was not changed. However, regarding sub-compartmental localisation in sperm head regions, for ZIP6 asthenozoospermia only decreased its acorn/crescent-like pattern. In contrast, ZIP14 immunostaining was altered in favour of crescent-like, as opposed to acorn-like and acorn/crescent-like patterns. The specific ZIPs localisation may reflect their different roles in sperm cell integrity and motility and may change over time. This is the first report of their specific compartmental and sub-compartmental localisation in ejaculated human sperm cells. Further research will lead to a greater understanding of the roles of ZIPs in sperm cell biology, which could positively influence procedures for human infertility therapy.

The aim of this study was to investigate lipofuscin origin in brown adipocytes of hyperinsulinaemic rats and the possible role of lipid peroxidation and iron in this process. Ultrastructural examination revealed hyperinsulinaemia-induced enhancement in the lipofuscin production, accompanied by an increase of mitochondrial damage in brown adipocytes. Extensive fusions of lipid droplets and mitochondria with lysosomes were also observed. Confocal microscopy showed lipofuscin autofluorescence emission in brown adipose tissue (BAT) after excitation at 488 nm and 633 nm, particularly in the insulin-treated groups. The presence and distribution of lipid peroxidation product, 4-hydroxy-2-nonenal (4-HNE), in brown adipocytes was assessed by immunohistochemical examination revealing its higher content after treatment with insulin. The iron content was quantified by electron dispersive X-ray analysis (EDX) showing its higher content in the hyperinsulinaemic groups. The ultrastucture of the majority of lipofuscin granules suggests their mitochondrial origin, which was additionally confirmed by their co-localization with ATP synthase. In conclusion, our results suggest that increased lipofuscinogenesis in the brown adipocytes of hyperinsulinaemic rats is a consequence of lipid peroxidation, mitochondrial damage and iron accumulation.

Mitochondria play an important role in sperm cell maturation and function. Here, we examined whether (and how) changes in sperm redox milieu affect the functional status of sperm mitochondria, that is, sperm functionality. Compared with the control, incubation in Tyrode's medium for 3 h, under noncapacitating conditions, decreased sperm motility, the amount of nitric oxide ((•)NO), the number of MitoTracker(®) Green FM (MT-G) positive mitochondria, and the expression of complexes I and IV of the mitochondrial respiratory chain. In turn, superoxide dismutase (SOD) mimic (M40403) treatment restored/increased these parameters, as well as the expression of endothelial nitric oxide synthase, manganese SOD, and catalase. These data lead to the hypothesis that M40403 improves mitochondrial functional state and motility of spermatozoa, as well as (•)NO might be involved in the observed effects of the mimic.