Corrigendum: 1270 nm near-infrared light as a novel vaccine adjuvant acts on mitochondrial photoreception in intradermal vaccines.

[This corrects the article DOI: 10.3389/fimmu.2022.1028733.].

Dietary fat types consumption association with obesity and coronary indices.

This article aims to study the different dietary fat types associated with obesity and coronary indices. A sample of 491 healthy adults was included in a cross-sectional manner. Dietary fats intake, obesity indices (conicity index (CI), body adiposity index (BAI), abdominal volume index (AVI), body roundness index (BRI), and weight-adjusted-waist index (WWI)), and cardiovascular indices (cardiometabolic index (CMI), lipid accumulation product (LAP), and atherogenic index of plasma (AIP)) were calculated and studied. Participants with an acceptable intake of omega-3 had a higher BRI score (1⋅90 ± 0⋅06 v. 1⋅70 ± 0⋅06). Participants with an unacceptable intake of cholesterol had a higher CI (1⋅31 ± 0⋅11 v. 1⋅28 ± 0⋅12; P = 0⋅011), AVI (20⋅24 ± 5⋅8 v. 18⋅33 ± 6⋅0; P < 0⋅001), BRI (2⋅00 ± 1⋅01 v. 1⋅70 ± 1⋅00; P = 0⋅003), WWI (11⋅00 ± 0⋅91 v. 10⋅80 ± 0⋅97; P = 0⋅032), and lower AIP (0⋅46 ± 0⋅33 v. 0⋅53 ± 0⋅33; P = 0⋅024). Total fat, saturated fat (SFA), and polyunsaturated fat (PUFA) intake had a significant moderate correlation with AVI and BRI. The monounsaturated fat (MUFA) intake had a significantly weak correlation with CI, AVI, BRI, WWI, and AIP. Cholesterol and omega-6 had weak correlations with all indices. Similar correlations were seen among male and female participants. The different types of fat intake significantly affected obesity and coronary indices, especially SFA and PUFA, as well as omega-3 and cholesterol. Gender and the dietary type of fat intake have a relationship to influence the indicators of both obesity and coronary indices.

Human papillomavirus expression in relation to biological behavior, Ki-67 proliferative marker, and P53 prognostic marker in Schneiderian papilloma.

Various malignant and benign tumors can arise in the sinonasal cavity, including inverted papilloma (IP), a benign neoplasm with unique clinical characteristics. However, the mechanisms involved in the recurrence, occurrence, and malignant transformation of IP remain debatable. This study aimed to investigate the impact of human papillomavirus (HPV) infections on IP by comparing the number of infections in cases with epithelial tissue dysplasia and explore the predictive role of proliferative and prognostic markers in dysplasia. Tissue blocks from 35 cases of sinonasal papilloma, collected between 2015 and 2021 from the laboratory archives of the Medical City of Ghazi Al-Hererri Hospital in Baghdad, Iraq, were immunohistochemically stained with monoclonal antibodies (mAbs) to detect Ki-67 and p53. A quantitative immunohistochemical analysis was conducted to analyze the results. Polymerase chain reaction (PCR) was performed to detect HPV genotypes 16/18 and 6/11 in the tissues. There was an insignificant increase in Ki-67 and p53 expression in inverted papillomas with dysplasia. HPV11 was the most prevalent genotype in 34.3% of the patients, followed by HPV16 and HPV18 in 31.4% of the patients for each virus. The least common virus detected was human papillomavirus 6 (8.6%), which did not show any significant association with the degree of dysplasia. Viral detection proliferation and apoptosis had no impact on tumor dysplasia amongst all the patients, showing no relationship with the evaluated cases.

Short-chain fatty acids reprogram metabolic profiles with the induction of reactive oxygen species production in human colorectal adenocarcinoma cells.

Short-chain fatty acids (SCFAs) exhibit anticancer activity in cellular and animal models of colon cancer. Acetate, propionate, and butyrate are the three major SCFAs produced from dietary fiber by gut microbiota fermentation and have beneficial effects on human health. Most previous studies on the antitumor mechanisms of SCFAs have focused on specific metabolites or genes involved in antitumor pathways, such as reactive oxygen species (ROS) biosynthesis. In this study, we performed a systematic and unbiased analysis of the effects of acetate, propionate, and butyrate on ROS levels and metabolic and transcriptomic signatures at physiological concentrations in human colorectal adenocarcinoma cells. We observed significantly elevated levels of ROS in the treated cells. Furthermore, significantly regulated signatures were involved in overlapping pathways at metabolic and transcriptomic levels, including ROS response and metabolism, fatty acid transport and metabolism, glucose response and metabolism, mitochondrial transport and respiratory chain complex, one-carbon metabolism, amino acid transport and metabolism, and glutaminolysis, which are directly or indirectly linked to ROS production. Additionally, metabolic and transcriptomic regulation occurred in a SCFAs types-dependent manner, with an increasing degree from acetate to propionate and then to butyrate. This study provides a comprehensive analysis of how SCFAs induce ROS production and modulate metabolic and transcriptomic levels in colon cancer cells, which is vital for understanding the mechanisms of the effects of SCFAs on antitumor activity in colon cancer.

Computational tools for exploring peptide-membrane interactions in gram-positive bacteria.

The vital cellular functions in Gram-positive bacteria are controlled by signaling molecules known as quorum sensing peptides (QSPs), considered promising therapeutic interventions for bacterial infections. In the bacterial system QSPs bind to membrane-coupled receptors, which then auto-phosphorylate and activate intracellular response regulators. These response regulators induce target gene expression in bacteria. One of the most reliable trends in drug discovery research for virulence-associated molecular targets is the use of peptide drugs or new functionalities. In this perspective, computational methods act as auxiliary aids for biologists, where methodologies based on machine learning and in silico analysis are developed as suitable tools for target peptide identification. Therefore, the development of quick and reliable computational resources to identify or predict these QSPs along with their receptors and inhibitors is receiving considerable attention. The databases such as Quorumpeps and Quorum Sensing of Human Gut Microbes (QSHGM) provide a detailed overview of the structures and functions of QSPs. The tools and algorithms such as QSPpred, QSPred-FL, iQSP, EnsembleQS and PEPred-Suite have been used for the generic prediction of QSPs and feature representation. The availability of compiled key resources for utilizing peptide features based on amino acid composition, positional preferences, and motifs as well as structural and physicochemical properties, including biofilm inhibitory peptides, can aid in elucidating the QSP and membrane receptor interactions in infectious Gram-positive pathogens. Herein, we present a comprehensive survey of diverse computational approaches that are suitable for detecting QSPs and QS interference molecules. This review highlights the utility of these methods for developing potential biomarkers against infectious Gram-positive pathogens.

Focal segmental glomerulosclerosis with a mutation in the mitochondrially encoded NADH dehydrogenase 5 gene: A case report.

NADH dehydrogenase 5 (ND5) is one of 44 subunits composed of Complex I in mitochondrial respiratory chain. Therefore, a mitochondrially encoded ND5 (MT-ND5) gene mutation causes mitochondrial oxidative phosphorylation (OXPHOS) disorder, resulting in the development of mitochondrial diseases. Focal segmental glomerulosclerosis (FSGS) which had podocytes filled with abnormal mitochondria is induced by mitochondrial diseases. An MT-ND5 mutation also causes FSGS. We herein report a Japanese woman who was found to have proteinuria and renal dysfunction in an annual health check-up at 29 years old. Because her proteinuria and renal dysfunction were persistent, she had a kidney biopsy at 33 years of age. The renal histology showed FSGS with podocytes filled with abnormal mitochondria. The podocytes also had foot process effacement and cytoplasmic vacuolization. In addition, the renal pathological findings showed granular swollen epithelial cells (GSECs) in tubular cells, age-inappropriately disarranged and irregularly sized vascular smooth muscle cells (AiDIVs), and red-coloured podocytes (ReCPos) by acidic dye. A genetic analysis using peripheral mononuclear blood cells and urine sediment cells detected the m.13513 G > A variant in the MT-ND5 gene. Therefore, this patient was diagnosed with FSGS due to an MT-ND5 gene mutation. Although this is not the first case report to show that an MT-ND5 gene mutation causes FSGS, this is the first to demonstrate podocyte injuries accompanied with accumulation of abnormal mitochondria in the cytoplasm.

Adipocytes in obesity: A perfect reservoir for SARS-CoV-2?

Research evidence suggests that adipocytes in obesity might facilitate SARS-CoV-2 replication, for it was only found in adipose tissue of individuals with overweight or obesity but not lean individuals who died from COVID-19. As lipid metabolism is key to adipocyte function, and viruses are capable of exploiting and manipulating lipid metabolism of host cells for their own benefit of infection, we hypothesize that adipocytes could not only impair host immune defense against viral infection, but also facilitate SARS-CoV-2 entry, replication and assembly as a reservoir to boost the viral infection in obesity. The latter of which could mainly be mediated by SARS-CoV-2 hijacking the abnormal lipid metabolism in the adipocytes. If these were to be confirmed, an approach to combat COVID-19 in people with obesity by taking advantage of the abnormal lipid metabolism in adipocytes might be considered, as well as modifying lipid metabolism of other host cells as a potential adjunctive treatment for COVID-19.

Hybrid computational models of multicellular tumour growth considering glucose metabolism.

Cancer cells metabolize glucose through metabolic pathways that differ from those used by healthy and differentiated cells. In particular, tumours have been shown to consume more glucose than their healthy counterparts and to use anaerobic metabolic pathways, even under aerobic conditions. Nevertheless, scientists have still not been able to explain why cancer cells evolved to present an altered metabolism and what evolutionary advantage this might provide them. Experimental and computational models have been increasingly used in recent years to understand some of these biological questions. Multicellular tumour spheroids are effective experimental models as they replicate the initial stages of avascular solid tumour growth. Furthermore, these experiments generate data which can be used to calibrate and validate computational studies that aim to simulate tumour growth. Hybrid models are of particular relevance in this field of research because they model cells as individual agents while also incorporating continuum representations of the substances present in the surrounding microenvironment that may participate in intracellular metabolic networks as concentration or density distributions. Henceforth, in this review, we explore the potential of computational modelling to reveal the role of metabolic reprogramming in tumour growth.

Expression, regulating mechanism and therapeutic target of KIF20A in multiple cancer.

Kinesin family member 20A (KIF20A) is a member of the kinesin family. It transports chromosomes during mitosis, plays a key role in cell division. Recently, studies proved that KIF20A was highly expressed in cancer. High expression of KIF20A was correlated with poor overall survival (OS). In this review, we summarized all the cancer that highly expressed KIF20A, described the role of KIF20A in cancer. We also organized phase I and phase II clinical trials of KIF20A peptides vaccine. All results indicated that KIF20A was a promising therapeutic target for multiple cancer.

Identifying Novel Genes and Variants in Immune and Coagulation Pathways Associated with Macular Degeneration.

Purpose: To select individuals and families with a low genetic burden for age-related macular degeneration (AMD), to inform the clinical diagnosis of macular disorders, and to find novel genetic variants associated with maculopathies. Design: Genetic association study based on targeted and whole-exome sequencing. Participants: A total of 758 subjects (481 individuals with maculopathy and 277 controls), including 316 individuals in 72 families. Methods: We focused on 150 genes involved in the complement, coagulation, and inflammatory pathways. Single-variant tests were performed on 7755 variants shared among ≥ 5 subjects using logistic regression. Gene-based tests were used to evaluate aggregate effects from rare and low-frequency variants (at minor allele frequency [MAF] ≤ 5% or ≤ 1%) in a gene using burden tests. For families whose affected members had a low burden of genetic risk based on known common and rare variants related to AMD, we searched for rare variants (MAF < 0.001) whose risk alleles occurred in ≥ 80% of affected individuals but not in controls. Immunohistochemistry was performed to determine the protein expression of a novel gene (coagulation factor II thrombin receptor-like 2 [F2RL2]) in retinal tissues. Main Outcome Measures: Genotypes and phenotypes of macular degeneration. Results: We confirmed the association of a synonymous variant in complement factor H (Ala473, rs2274700, proxy to intronic rs1410996, r 2  = 1) with maculopathy (odds ratio, 0.64; P = 4.5 × 10-4). Higher AMD polygenic risk scores (PRSs) were associated with intermediate and advanced AMD. Among families with low PRSs and no known rare variants for maculopathy, we identified 2 novel, highly penetrant missense rare variants in ADAM15, A disintegrin and metalloprotease, metallopeptidase domain 15 (p.Arg288Cys) and F2RL2 (p.Leu289Arg). Immunohistochemistry analyses revealed F2RL2 protein expression in cone photoreceptor outer segments and Müller glia cells of human and pig retinas. Coagulation factor II thrombin receptor-like 2 expression appeared increased in fibrotic areas in advanced AMD samples with neovascularization, suggesting that F2RL2 may play a role in the progression to advanced macular disease. Conclusions: New missense rare variants in the genes ADAM15 and F2RL2 were associated with maculopathies. Results suggest that novel genes related to the coagulation and immune pathways may be involved in the pathogenesis of macular diseases.

Hexane fraction of Globimetula braunii induces mitochondria-mediated apoptosis in Plasmodium berghei-infected mice.

Background: Apoptosis is a common pathology in malaria and most antimalarial drugs induce apoptosis during chemotherapy. Globimetula braunii is an African mistletoe used for the treatment of malaria but its effect on mitochondria-mediated apoptosis is not known. Methods: Malarial infection was induced by the intraperitoneal injection of NK 65 strain Plasmodium berghei-infected erythrocytes into mice which were treated with graded doses (100-400 mg/kg) of methanol extract (ME), and fractions of n-hexane, dichloromethane, ethylacetate and methanol (HF, DF, EF and MF) for 9 days after the confirmation of parasitemia. Artequine (10 mg/kg) was used as control drug. The fraction with the highest antiplasmodial activity was used (same dose) to treat mice infected with chloroquine-resistant (ANKA) strain for 5 consecutive days after the confirmation of parasitemia. P-alaxin (10 mg/kg) was used as control drug. On the last day of the treatment, liver mitochondria were isolated and mitochondrial Permeability Transition (mPT) pore opening, mitochondrial F0F1 ATPase (mATPase) activity, lipid peroxidation (mLPO) and liver deoxyribonucleic acid (DNA) fragmentation were assessed spectrophotometrically. Caspases 3 and 9 were determined by Enzyme-Linked Immunosorbent Assay (ELISA) technique. Cytochrome c, P53, Bcl-2-associated X protein (Bax), and B-cell lymphoma-2 (Bcl2) were determined via immunohistochemistry. Phytochemical constituents of the crude methanol extract of Globimetula braunii were determined via the Gas Chromatography-Mass Spectrometry (GC-MS) analysis. Results: There was large amplitude mPT induction by malaria parasites, extract and fractions of Globimetula braunii. At 400 mg/kg, HF significantly (p < 0.01) downregulated mATPase activity, and mLPO in both (susceptible and resistant) models, caused DNA fragmentation (P < 0.0001), induced caspases activation, P53, bax and cytochrome c release but downregulated Bcl2 in both models. The GC-MS analysis of methanol extract of Globimetula braunii showed that α-amyrin is the most abundant phytochemical. Conclusion: The n-hexane fraction of Globimetula braunii induced mitochondrial-mediated apoptosis through the opening of the mitochondrial pore, fragmentation of genomic DNA, increase in the levels of P53, bax, caspase 3 and 9 activation and cytochrome c release with concomitant decrease in the level of Bcl2. α-Amyrin is a triterpene with apoptotic effects.

Clinical Benefits of Sodium-Glucose Cotransporter 2 Inhibitors and the Mechanisms Underlying Their Cardiovascular Effects.

In addition to showing antidiabetic effects, sodium-glucose cotransporter 2 (SGLT2) inhibitors also reduce cardiovascular events in patients with type 2 diabetes mellitus. In major trials of cardiovascular outcomes, SGLT2 inhibitors have been shown to improve cardiovascular and renal outcomes, including reduced rehospitalization in patients with heart failure, regardless of the presence of diabetes. A recent report showed that the benefits of SGLT2 inhibitors in terms of cardiovascular deaths/admissions caused by heart failure and reduced ejection fraction were greater in Asians than in Whites. In this review, the first part demonstrates the results of recent clinical trials and their clinical implications and outlines current trials and upcoming research areas. The second part provides a general overview of the current understanding of the mechanisms of the cardiovascular benefits of SGLT2 inhibitors.

Prospective bacterial and fungal sources of hyaluronic acid: A review.

The unique biological and rheological properties make hyaluronic acid a sought-after material for medicine and cosmetology. Due to very high purity requirements for hyaluronic acid in medical applications, the profitability of streptococcal fermentation is reduced. Production of hyaluronic acid by recombinant systems is considered a promising alternative. Variations in combinations of expressed genes and fermentation conditions alter the yield and molecular weight of produced hyaluronic acid. This review is devoted to the current state of hyaluronic acid production by recombinant bacterial and fungal organisms.

Development of appropriate fatty acid formulations to raise the contractility of constructed myocardial tissues.

Introduction: Heart disease is a major cause of mortality worldwide, and the annual number of deaths due to heart disease has increased in recent years. Although heart failure is usually managed with medicines, the ultimate treatment for end-stage disease is heart transplantation or an artificial heart. However, the use of these surgical strategies is limited by issues such as thrombosis, rejection and donor shortages. Regenerative therapies, such as the transplantation of cultured cells and tissues constructed using tissue engineering techniques, are receiving great attention as possible alternative treatments for heart failure. Research is ongoing into the potential clinical use of cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs). However, the energy-producing capacity of cardiomyocytes maintained under previous culture conditions is lower than that of adult primary cardiomyocytes due to immaturity and a reliance on glucose metabolism. Therefore, the aims of this study were to compare the types of fatty acids metabolized between cardiomyocytes in culture and heart cells in vivo and investigate whether the addition of fatty acids to the culture medium affected energy production by cardiomyocytes. Methods: A fatty acid-containing medium was developed based on an analysis of fatty acid consumption by rat primary cardiomyocytes (rat-CMs), and the effects of this medium on adenosine triphosphate (ATP) production were investigated through bioluminescence imaging of luciferase-expressing rat-CMs. Next, the fatty acid content of the medium was further adjusted based on analyses of fatty acid utilization by porcine hearts and hiPSC-CMs. Oxygen consumption analyses were performed to explore whether the fatty acid-containing medium induced hiPSC-CMs to switch from anaerobic metabolism to aerobic metabolism. Furthermore, the effects of the medium on contractile force generated by hiPSC-CM-derived tissue were evaluated. Results: Rat serum, human serum and porcine plasma contained similar types of fatty acid (oleic acid, stearic acid, linoleic acid, palmitic acid and arachidonic acid). The types of fatty acid consumed were also similar between rat-CMs, hiPSC-CMs and porcine heart. The addition of fatty acids to the culture medium increased the bioluminescence of luciferase-expressing rat-CMs (an indirect measure of ATP level), oxygen consumption by hiPSC-CMs, and contractile force generated by cardiac tissues constructed from hiPSC-CMs. Conclusions: hiPSC-CMs metabolize similar types of fatty acid to those consumed by rat-CMs and porcine hearts. Furthermore, the addition of these fatty acids to the culture medium increased energy production by rat-CMs and hiPSC-CMs and enhanced the contractility of myocardial tissue generated from hiPSC-CMs. These findings suggest that the addition of fatty acids to the culture medium stimulates aerobic energy production by cardiomyocytes through ß-oxidation. Since cardiomyocytes cultured in standard media rely primarily on anaerobic glucose metabolism and remain in an immature state, further research is merited to establish whether the addition of fatty acids to the culture medium would improve the energy-producing capacity and maturity of hiPSC-CMs and cardiac tissue constructed from these cells. It is possible that optimizing the metabolism of cultured cardiomyocytes, which require high energy production to sustain their contractile function, will improve the properties of hiPSC-CM-derived tissue, allowing it to be better utilized for disease modeling, drug screening and regenerative therapies for heart failure.

Trabecular Meshwork Mitochondrial Function and Oxidative Stress: Clues to Racial Disparities of Glaucoma.

Purpose: To identify racial differences of oxidative damage and stress and mitochondrial function in human trabecular meshwork (TM). Design: Experimental study. Participants: One hundred seventy-three eyes of 173 patients undergoing intraocular surgery provided aqueous humor (AH) for analysis. Trabecular meshwork tissues from eye bank donors were used as healthy controls for primary cell culture. Methods: Enzyme-linked immunosorbent assay methods were used to measure 8-hydroxy-2-deoxyguanosine (8-OHdG), an oxidative damage marker, in AH comparing Black and White Americans. Human TM primary cultured cells from Black and White donors were used for adenosine triphosphate (ATP) measurement under high and low oxygen culture conditions. Complex I activity was measured in mitochondrial fractions isolated from cultured TM cells. Mitochondrial quantification was performed by translocase of outer mitochondrial membrane 20 (TOMM20) Western blot. Intracellular reactive oxygen species (ROS) production was measured in live TM cells. Main Outcome Measures: Oxidative damage in AH, ATP production, complex I activity, mitochondrial quantification, and intracellular ROS in cultured TM cells stratified by racial background. Results: Aqueous humor samples (75 Black, 98 White) displayed significantly higher 8-OHdG levels (P = 0.024) in Black compared with White patients with severe stage glaucoma. Using cultured healthy donor TM cells, ATP production was higher in Black than White TM cells (P = 0.002) in low oxygen culture conditions. Complex I activity was not statistically different in Black compared with White TM cells, but TOMM20 expression was higher in Black versus White cells (P = 0.001). In response to hydrogen peroxide challenge, ROS production was significantly higher in Black compared to White TM cells (P = 0.004). Conclusions: Significantly higher 8-OHdG levels in AH of Black compared with White patients with severe glaucoma indicated that oxidative damage may be a risk factor in glaucoma pathogenesis or the result of distinct pathologic features in the Black population. To identify potential origins or causes of this damage, our data showed that healthy Black cultured TM cells have higher ATP and ROS levels, with increased quantity of mitochondria, compared with White TM cells. These findings indicate that mitochondrial alterations and increased oxidative stress may influence racial disparities of glaucoma.

Puerarin improves skeletal muscle strength by regulating gut microbiota in young adult rats.

Background: Sarcopenia is an age-related skeletal muscle dysfunction syndrome that is lacking validated treatments. Maximizing muscle strength in young adulthood may be a promising way to prevent sarcopenia in the elderly. The phytomolecule puerarin has been extensively used in clinical practice and reported to increase energy metabolism in skeletal muscle by directly targeting the skeletal muscle fiber. However, the bioavailability of puerarin is very poor, and almost 93% of puerarin stays in the intestine until excretion. Therefore, we hypothesize that puerarin may regulate gut microbiota to improve skeletal muscle strength and/or mass in adults. Methods: Twenty three-month old male Sprague Dawley rats were divided into two groups according to average weights, puerarin group (puerarin dissolved in 0.5% CMC-Na, 150 â€‹mg/kg/day, N â€‹= â€‹10), and control group (equal volume 0.5% CMC-Na, N â€‹= â€‹10). The treatment lasted for 8 weeks. Muscle weight, muscle fiber types and cross-sectional area (CSA), ex vivo muscle contraction test and grip strength were measured. 16S rDNA sequencing was employed to evaluate the gut microbiota composition in the sample of cecal content. Short-chain fatty acids (SCFAs) in cecal and serum were analyzed by gas chromatography-mass spectrometry. Adenosine triphosphate (ATP) concentration in skeletal muscle was also detected. Pearson's correlation was used to analyze the relations between SCFAs, ATP concentration and muscle function. Results: After puerarin treatment, grip strength, the specific twitch force, and the tetanic forces in the soleus (SOL) and extensor digitorum longus (EDL) muscle were significantly higher than those of the control group. The percentage and CSA of type II muscle fiber in EDL was higher in the puerarin group than those in the control group. Puerarin treatment significantly changed the gut microbial constitutes. Two SCFAs-productive microbiota, the families Peptococcaceae and Closteridiales, were significantly higher in the puerarin group than those in the control group, while the ratio of Prevotellaceae/Bacteroidaceae (P/B), a muscle atrophy indicator, was lower in the puerarin group. As expected, there were significant linear correlations between the concentrations of SCFAs, including cecal total SCFAs, serum n-butyric acid and total SCFAs, and skeletal muscle strength and function, including the twitch force and tetanic force of SOL and EDL, as well as the forelimb grip strength. Conclusion: In conclusion, puerarin improved the forelimb grip strength and muscle contraction function in young adult rats. The underlying mechanism may include that puerarin increased SCFAs production by regulating gut microbiota, augmented ATP synthesis and skeletal muscle strength. The translational potential of this article : Our study finds that a clinical used phytomolecule puerarin has the potential of improving skeletal muscle strength in young adult rats. As puerarin has long-term clinical experience and shows good safety, it might be a potential candidate for developing muscle strengthening agents.

Ischemic preconditioning upregulates Mitofusin2 and preserves muscle strength in tourniquet-induced ischemia/reperfusion.

Background: Tourniquet-induced ischemia and reperfusion (I/R) has been related to postoperative muscle atrophy through mechanisms involving protein synthesis/breakdown, cellular metabolism, mitochondrial dysfunction, and apoptosis. Ischemic preconditioning (IPC) could protect skeletal muscle against I/R injury. This study aims to determine the underlying mechanisms of IPC and its effect on muscle strength after total knee arthroplasty (TKA). Methods: Twenty-four TKA patients were randomized to receive either sham IPC or IPC (3 cycles of 5-min ischemia followed by 5-min reperfusion). Vastus medialis muscle biopsies were collected at 30 â€‹min after tourniquet (TQ) inflation and the onset of reperfusion. Western blot analysis was performed in muscle protein for 4-HNE, SOD2, TNF-ɑ, IL-6, p-Drp1ser616, Drp1, Mfn1, Mfn2, Opa1, PGC-1ɑ, ETC complex I-V, cytochrome c, cleaved caspase-3, and caspase-3. Clinical outcomes including isokinetic muscle strength and quality of life were evaluated pre- and postoperatively. Results: IPC significantly increased Mfn2 (2.0 â€‹± â€‹0.2 vs 1.2 â€‹± â€‹0.1, p â€‹= â€‹0.001) and Opa1 (2.9 â€‹± â€‹0.3 vs 1.9 â€‹± â€‹0.2, p â€‹= â€‹0.005) proteins expression at the onset of reperfusion, compared to the ischemic phase. There were no differences in 4-HNE, SOD2, TNF-ɑ, IL-6, p-Drp1ser616/Drp1, Mfn1, PGC-1ɑ, ETC complex I-V, cytochrome c, and cleaved caspase-3/caspase-3 expression between the ischemic and reperfusion periods, or between the groups. Clinically, postoperative peak torque for knee extension significantly reduced in the sham IPC group (-16.6 [-29.5, -3.6] N.m, p â€‹= â€‹0.020), while that in the IPC group was preserved (-4.7 [-25.3, 16.0] N.m, p â€‹= â€‹0.617). Conclusion: In TKA with TQ application, IPC preserved postoperative quadriceps strength and prevented TQ-induced I/R injury partly by enhancing mitochondrial fusion proteins in the skeletal muscle. The translational potential of this article: Mitochondrial fusion is a potential underlying mechanism of IPC in preventing skeletal muscle I/R injury. IPC applied before TQ-induced I/R preserved postoperative quadriceps muscle strength after TKA.

Targeting Myocardial Mitochondria-STING-Polyamine Axis Prevents Cardiac Hypertrophy in Chronic Kidney Disease.

Chronic kidney disease (CKD) is well recognized as a distinct contributor to cardiac hypertrophy, while the underlying mechanism remains incompletely understood. Here, the authors show that myocardial mitochondrial oxidative damage is early and prominent in CKD and distinctively stimulates the STING-NFκB pathway by releasing mitochondrial DNA to drive cardiac hypertrophy. Furthermore, the authors reveal that ornithine decarboxylase (ODC1)-putrescine metabolic flux is transactivated by NFκB and is required for the STING-NFκB pathway to drive cardiac hypertrophy. Finally, genetic or pharmacologic inhibition of the myocardial mitochondria-STING-NFκB-ODC1 axis significantly prevents CKD-associated cardiac hypertrophy. Therefore, targeting the myocardial mitochoandria-STING-NFκB-ODC1 axis is a promising therapeutic strategy for cardiac hypertrophy in patients with CKD.

Functional importance of coacervation to convert calcium polyphosphate nanoparticles into the physiologically active state.

Inorganic polyphosphates (polyP) are of increasing medical interest due to their unprecedented ability to exhibit both morphogenetic and ATP-delivering properties. However, these polymers are only physiologically active in the coacervate state, but not as amorphous nanoparticles (NP), the storage form of the polymer. Little is known about the mechanism of formation and interconversion of these two distinct polyP phases in the presence of metal ions. Based on in silico simulation studies, showing a differential clustering of polyP and calcium ions, the pH-dependent NP and coacervate formation of polyP was examined experimentally. Turbidimetric studies showed that Ca-polyP coacervate formation at pH 7 is a slow process compared to NP formation at pH 10. In FTIR spectra, the asymmetric stretching vibration signal of the internal (PO2)- units, which is present in the Ca-polyP coacervate formed at pH 7, disappears in the NP formed at pH 10 using the conventional method (dropping of a CaCl2 solution into a Na-polyP solution). Surprisingly, when reversing the procedure, adding Na-polyP to CaCl2, a coacervate is obtained at both pH 7 and pH 10, as confirmed by SEM and FTIR analyses. The (PO2)- signal also disappears when Ca-polyP-NP are exposed to peptides, leading to the transformation of the NP into the coacervate phase. From these results, a mechanistic model of pH-dependent coacervate and NP formation is proposed that considers not only electrostatic ion-ion but also ion-dipole interactions. Functional studies revealed a delayed polyP release kinetics for Ca-polyP-NP embedded in a hydrogel due to NP/coacervate conversion. Human A549 epithelial cells grown on the coacervate show increased proliferation and ATP production compared to cells cultured on particulate polyP. Ca-polyP NP taken up by endocytosis undergo intracellular coacervate transformation. Understanding the differential expression of the two polyP phases is of functional importance for the potential therapeutic application of this physiological, regeneratively active polymer.

Extracellular ATP and its derivatives provide spatiotemporal guidance for bone adaptation to wide spectrum of physical forces.

ATP is a ubiquitous intracellular molecule critical for cellular bioenergetics. ATP is released in response to mechanical stimulation through vesicular release, small tears in cellular plasma membranes, or when cells are destroyed by traumatic forces. Extracellular ATP is degraded by ecto-ATPases to form ADP and eventually adenosine. ATP, ADP, and adenosine signal through purinergic receptors, including seven P2X ATP-gated cation channels, seven G-protein coupled P2Y receptors responsive to ATP and ADP, and four P1 receptors stimulated by adenosine. The goal of this review is to build a conceptual model of the role of different components of this complex system in coordinating cellular responses that are appropriate to the degree of mechanical stimulation, cell proximity to the location of mechanical injury, and time from the event. We propose that route and amount of ATP release depend on the scale of mechanical forces, ranging from vesicular release of small ATP boluses upon membrane deformation, to leakage of ATP through resealable plasma membrane tears, to spillage of cellular content due to destructive forces. Correspondingly, different P2 receptors responsive to ATP will be activated according to their affinity at the site of mechanical stimulation. ATP is a small molecule that readily diffuses through the environment, bringing the signal to the surrounding cells. ATP is also degraded to ADP which can stimulate a distinct set of P2 receptors. We propose that depending on the magnitude of mechanical forces and distance from the site of their application, ATP/ADP profiles will be different, allowing the relay of information about tissue level injury and proximity. Lastly, ADP is degraded to adenosine acting via its P1 receptors. The presence of large amounts of adenosine without ATP, indicates that an active source of ATP release is no longer present, initiating the transition to the recovery phase. This model consolidates the knowledge regarding the individual components of the purinergic system into a conceptual framework of choreographed responses to physical forces.