Cellular Physiology and Biochemistry最新文献

Background/aims: All body functions are activated, synchronized and controlled by a substantial, complex network, the nervous system. Upon injury, pathophysiology of the nerve injury proceeds through different paths. The axon may undergo a degenerative retraction from the site of injury for a short distance unless the injury is near to the cell body, in which case it continues to the soma and undergoes retrograde neuronal degeneration. Otherwise, the distal section suffers from Wallerian degeneration, which is marked by axonal swelling, spheroids, and cytoskeleton degeneration. The objective of the study was to evaluate the potential of mesenchymal stem cell laden neural scaffold and insulin-like growth factor I (IGF-I) in nerve regeneration following sciatic nerve injury in a rat model.

Methods: The animals were anaesthetized and a cranio-lateral incision over left thigh was made. Sciatic nerve was exposed and crush injury was introduced for 90 seconds using haemostat at second locking position. The muscle and skin were sutured in routine fashion and thus the rat model of sciatic crush injury was prepared. The animal models were equally distributed into 5 different groups namely A, B, C, D and E and treated with phosphate buffer saline (PBS), carbon nanotubes based neural scaffold only, scaffold with IGF-I, stem cell laden scaffold and stem cell laden scaffold with IGF-I respectively. In vitro scaffold testing was performed. The nerve regeneration was assessed based on physico-neuronal, biochemical, histopathological examination, and relative expression of NRP-1, NRP-2 and GAP-43 and scanning electron microscopy.

Results: Sciatic nerve injury model with crush injury produced for 90 seconds was standardized and successfully used in this study. All the biochemical parameters were in normal range in all the groups indicating no scaffold related changes. Physico-neuronal, histopathological, relative gene expression and scanning electron microscopy observations revealed appreciable nerve regeneration in groups E and D, followed by C and B. Restricted to no regeneration was observed in group A.

Conclusion: Carbon nanotubes based scaffold provided electro-conductivity for proper neuronal regeneration while rat bone marrow-derived mesenchymal stem cells were found to induce axonal sprouting, cellular transformation; whereas IGF-I induced stem cell differentiation, myelin synthesis, angiogenesis and muscle differentiation.

Background/aims: Currently, it is proven that the cellular metabolism of nitric oxide is necessary to maintain optimal health and adaptation of the organism to the impact of various environmental factors. The aim of this work was to reveal the biological role of nitric oxide, its metabolic changes, and its mechanism of action in tissues under hypoxia, as well as the possibility of tissue metabolism correction through NO-dependent systems under the influence of Krebs cycle intermediates.

Methods: A systematic assessment of the effect of succinate (SC, 50 mg/kg b.w.) and α-ketoglutarate (KGL, 50 mg/kg b.w.) in the regulation of oxygendependent processes in rats (mitochondrial oxidative phosphorylation, microsomal oxidation, intensity of lipid peroxidation processes, and the state of the antioxidant defense system) depending on functional changes in nitric oxide production during hypoxia was evaluated. The state of the nitric oxide system was estimated spectrophotometrically by determination of the concentration of its stable nitrite anion metabolite (NO₂ -). The levels of catecholamines were estimated from the content of epinephrine and norepinephrine using the differentially fluorescent method. The activity of cytochrome P450-dependent aminopyrine-N-demethylase was determined with the Nash reagent.

Results: Tissue hypoxia and metabolic disorders caused by this condition through changes in the content of catecholamines (epinephrine, norepinephrine, dopamine, DOPA) as well as the cholinesterase-related system (acetylcholine content and acetylcholinesterase activity) were the studied experimental parameters under acute hypoxia (AH, 7% O₂ in N₂, 30 min). The activation of lipid peroxidation and oxidatively modified proteins and an increase in the epinephrine content in AH are associated with an increased role of SC and a decrease in KGL as substrates of oxidation in mitochondria. A more pronounced effect of exogenous KGL, compared to SC, on the content of nitrite anion as a stable metabolite of nitric oxide in the liver under acute hypoxia against the background of a decrease in the intensity of lipid peroxidation processes was revealed. The activation of SC-dependent mitochondrial oxidative processes caused by AH was found to decrease in animals after an intermittent hypoxia training (IHT) course. IHT (7% O₂ in N₂, 15-min, 5 times daily, 14 days) prevented the activation of oxidative stress in tissues and blood after the AH impact and increased the efficiency of energy-related reactions in the functioning of hepatic mitochondria through increased oxidation of KGL.

Conclusion: The studied effects of adaptation are mediated by an increase in the role of NO-dependent mechanisms, as assessed by changes in the pool of nitrates, nitrites, carbamides, and total polyamines.

Background/aims: Microglial cells play a crucial role in the development of neuroinflammation in response to harmful stimuli, such as infection, ischemia or injury. Their chronic activation, however, is associated with a progression of neurodegenerative diseases. Therefore, looking for potential factors limiting microglial activation, the effect of docosahexaenoic acid (DHA) on the inflammatory response and TREM2-dependent phagocytic activity in microglia was investigated.

Methods: In LPS-induced primary microglia preincubated with DHA, or without preincubation the expression of ATF3 and TREM2 genes and TREM2, Syk, Akt proteins were determined by RT-PCR and WB, respectively. Cell viability was assayed by MTT and cytokine and chemokine expression was determined by the Proteome Profiler assay. Moreover, the phagocytic activity of microglia was assayed using immunofluorescence.

Results: We found that DHA significantly increased the expression of ATF3 , and decreased the levels of CINC-1, CINC-2αβ, CINC-3 chemokines, IL-1α and IL-1β cytokines, and ICAM-1 adhesion protein. Additionally, preincubation of microglia with DHA resulted in increased Src/Syk kinases activation associated with increased phagocytic microglia activity.

Conclusion: These findings indicate that DHA efficiently inhibits ATF3-dependent release of proinflammatory mediators and enhances phagocytic activity of microglia. The study provides a new mechanism of DHA action in reactive microglia, which may help limit neuronal damage caused by the pro-inflammatory milieu in the brain.

Suppressor of Ty homolog-5 (SPT5) discovered in the yeast mutant screens as a suppressor of mutation caused by the insertion of the Transposons of yeast (Ty) element along with SPT4, with which it forms a holoenzyme complex known as DRB sensitivity-inducing factor (DSIF) and plays an essential role in the regulation of transcription. SPT5 is a highly conserved protein across all three domains of life and performs critical functions in transcription, starting from promoter-proximal pausing to termination. We also highlight the emerging role of SPT5 in other non-canonical functions, such as the regulation of post-translational modifications (PTM) and the transcriptional regulation of non-coding genes. Also, in brief, we highlight the clinical implications of SPT5 dysregulation.

Background/aims: Swine erysipelas is a disease caused by Erysipelothrix rhusiopathiae, a Gram-positive bacillus, which has great economic importance because it leads to the loss of the swine herd. To control this disease, animals are immunized with a cellular vaccine of killed or attenuated E. rhusiopathiae, but even with herd vaccination, cases of swine erysipelas outbreaks have been reported in the United States, China and Japan, leading to the search for other antigenic components of the bacteria that may promote greater protection against E. rhusiopathiae. The surface protein SpaA from E. rhusiopathiae has been shown to be a candidate to constitute a subunit vaccine, since it has already been reported to induce a host immune response against the bacterium. DnaK, a hsp70 molecular chaperone, also seems to be a good candidate in the composition of a vaccine, as it has been demonstrated to be an antigenic protein of the bacteria.

Methods: This work evaluated the immunogenicity and protection induced by the E. rhusiopathiaee SpaA and DnaK recombinant proteins in a murine model, by intramuscular administration to mice with two doses of 100 µg at 21-day interval between them. The candidate proteins were tested either separately and together, compared with the commercial vaccine and the non-vaccination condition, and mice were challenged with a virulent strain of E. rhusiopathiae. Serum was collected to assess the produced antibodies and peripheral blood cells, whereas spleen and kidney tissues were assayed for E. rhusiopathiae presence by colony counting.

Results: A survival curve of the animals was performed, which confirmed the protection induced by the proteins. IgG antibodies increased in the animal serum inoculated with the proteins when compared to the control, and a significant delay in disease symptoms was observed.

Conclusion: These results suggest that E. rhusiopathiae DnaK and SpaA are immunogenic in mice and interfere with the disease development.

Background/aims: Cancer cell multidrug resistance induced by paclitaxel contributes to the high failure rates of chemotherapy and relapse of the disease. Several mechanisms have been described that underlie the observed resistance, including the overexpression of ABCB1 (P-glycoprotein), which represents an ATP-binding cassette (ABC) transmembrane protein, and its functional occurrence in lysosomal membranes is linked to drug accumulation in these organelles.

Methods: Using clinically-relevant models of paclitaxel-resistant triple-negative breast cancer and non-small cell lung cancer cell lines, we provide evidence for the role of ABCC subfamily members in the lysosomal sequestration of drugs in multidrug resistant phenotypes. Proteins expression level and its cellular localisation was measured using Western Blot and confocal microscopy. Drug accumulation was analysed by confocal microscopy and flow cytometry. Drug cytotoxicity was tested using resasurin assay and anexin V propidium iodide staining.

Results: Regardless of the alteration in gene expression, paclitaxel induced the intracellular redistribution of ABCC3, ABCC5 and ABCC10 and their enrichment in lysosomes. The use of ABCC inhibitors and transient silencing of these three genes limited the accumulation of doxorubicin and paclitaxel-OregonGreen488 in lysosomes, while having little impact on the total drug level inside cells. The cancer cells were also sensitized to various structurally unrelated chemotherapeutics of differing acidity.

Conclusion: The results suggest that lysosome membranes anchored ABCC proteins which remained functionally active and were capable to load chemotherapeutics into lysosomes in paclitaxel-resistant cancer cells. Therefore, targeting of lysosomal ABCC transporters may help to overcome paclitaxel-induced resistance by reducing the accumulation of drugs in lysosomes.

The liver is the main metabolic organ and functions to regulate many physiological functions in the human body. Approximately 70% of liver mass consists of hepatic cells (hepatocytes), which execute the liver's metabolic processes. When liver damage progresses to a chronic condition, such as end-stage liver disease (ESLD) or cirrhosis of the liver, the patient's only option for therapy is organ transplantation if the supply of available transplanted organs is insufficient to meet the patient's needs. The fundamental objective of the search for alternatives to organ transplantation has been to make liver tissue replacement more accessible and to produce hepatic and bioartificial liver tissue. Multiple hepatic cell lineages can be formed from human-induced pluripotent stem cells (hiPSCs) from embryoid bodies to become mature hepatocytes. hiPSCs also show a promising source for manufacturing human liver spheroids and are made to produce three-dimensional hepatobiliary organoids, and in some ways, it also briefly highlights important features of early hepatogenesis. Unquestionably, the art of cell culture has evolved to include the use of organoid technology as a resource for learning human biology in the context of health and illness. Organoids are essentially miniature organs that can grow in a three-dimensional matrix to resemble genuine organs in terms of both structure and function. This review summarized alternative protocols to differentiate hepatocytes from iPSC and to produce liver organoids based on iPSC in various ways. The growth of human iPSCs into liver organoids has been accomplished using several procedures.

Background/aims: Recombinant adeno-associated viruses (rAAV) are an important tool for lung targeted gene therapy. Substitution of tyrosine with phenylalanine residues (Y-F) in the capsid have been shown to protect the AAV vector from ubiquitin/proteasome degradation, increasing transduction efficiency. We tested the mutant Y733F-AAV8 vector for mucus diffusion, as well as the safety and efficacy of pigment epithelium-derived factor (PEDF) gene transfer to the lung.

Methods: For this purpose, Y733F-AAV8-PEDF (10¹⁰ viral genome) was administered intratracheally to C57BL/6 mice. Lung mechanics, morphometry, and inflammation were evaluated 7, 14, 21, and 28 days after injection.

Results: The tyrosine-mutant AAV8 vector was efficient at penetrating mucus in ex vivo assays and at transferring the gene to lung cells after in vivo instillation. Increased levels of transgene mRNA were observed 28 days after vector administration. Overexpression of PEDF did not affect in vivo lung parameters.

Conclusion: These findings provide a basis for further development of Y733F-AAV8-based gene therapies for safe and effective delivery of PEDF, which has anti-angiogenic, anti-inflammatory and anti-fibrotic activities and might be a promising therapy for lung inflammatory disorders.