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ABSTRACT Helicobacter pylori vacuolating cytotoxin A (VacA) is an intracellular-acting protein exotoxin that induces mitochondrial dysfunction and energy depletion within host cells. Although exposure to VacA results in mitochondrial dysfunction, one recent study revealed that, following limited exposure to VacA, mitochondrial function and cellular ATP levels were restored in a time-dependent manner. Studies performed to address the mechanism by which host cells detect and respond to intracellular VacA identified the adenosine monophosphate (AMP)-activated protein kinase (AMPK) as a sensor of toxin-dependent alterations in cellular energy status. Activation of AMPK in response to VacA was demonstrated to orchestrate alterations in mitochondrial dynamics which resulted in restoration of mitochondrial function. Specifically, upregulation of dynamin-related protein 1 (Drp-1)-dependent mitochondrial fission resulted in reversible fragmentation of filamentous mitochondria and time-dependent reduction in mitochondrial-associated VacA, suggesting that fragmentation is important for removal of VacA from mitochondria. Cells with reduced levels of Drp-1 were more susceptible to VacA-dependent cell death, suggesting that mitochondrial dynamics is important for maintaining cell viability through the reduction in mitochondrial-associated toxin. Collectively, these studies support a model that cellular recovery and survival in response to VacA-dependent mitochondrial dysfunction is linked to host cell modulation of mitochondrial dynamics. This study provides new insights into cellular recognition and responses to intracellular-acting toxin modulation of host cell function, which could be relevant for the growing list of pathogenic microbes and viruses identified that target mitochondria as part of their virulence strategies. IMPORTANCE Persistent human gastric infection with Helicobacter pylori is the single most important risk factor for development of gastric malignancy, which is one of the leading causes of cancer-related deaths worldwide. An important virulence factor for Hp colonization and severity of gastric disease is the protein exotoxin VacA, which is secreted by the bacterium and modulates functional properties of gastric cells. VacA acts by damaging mitochondria, which impairs host cell metabolism through impairment of energy production. Here, we demonstrate that intoxicated cells have the capacity to detect VacA-mediated damage, and orchestrate the repair of mitochondrial function, thereby restoring cellular health and vitality. This study provides new insights into cellular recognition and responses to intracellular-acting toxin modulation of host cell function, which could be relevant for the growing list of pathogenic microbes and viruses identified that target mitochondria as part of their virulence strategies.

Abstract Background Previously, we isolated a riboflavin-overproducing Ashbya gossypii mutant (MT strain) and discovered some mutations in genes encoding flavoproteins. Here, we analyzed the riboflavin production in the MT strain, in view of flavoproteins, which are localized in the mitochondria. Results In the MT strain, mitochondrial membrane potential was decreased compared with that in the wild type (WT) strain, resulting in increased reactive oxygen species. Additionally, diphenyleneiodonium (DPI), a universal flavoprotein inhibitor, inhibited riboflavin production in the WT and MT strains at 50 µM, indicating that some flavoproteins may be involved in riboflavin production. The specific activities of NADH and succinate dehydrogenases were significantly reduced in the MT strain, but those of glutathione reductase and acetohydroxyacid synthase were increased by 4.9- and 25-fold, respectively. By contrast, the expression of AgGLR1 gene encoding glutathione reductase was increased by 32-fold in the MT strain. However, that of AgILV2 gene encoding the catalytic subunit of acetohydroxyacid synthase was increased by only 2.1-fold. These results suggest that in the MT strain, acetohydroxyacid synthase, which catalyzes the first reaction of branched-chain amino acid biosynthesis, is vital for riboflavin production. The addition of valine, which is a feedback inhibitor of acetohydroxyacid synthase, to a minimal medium inhibited the growth of the MT strain and its riboflavin production. In addition, the addition of branched-chain amino acids enhanced the growth and riboflavin production in the MT strain. Conclusion The significance of branched-chain amino acids for riboflavin production in A. gossypii is reported and this study opens a novel approach for the effective production of riboflavin in A. gossypii.

Exosomes are nanosized extracellular vesicles secreted by various cell types, including those of the immune system, such as natural killer (NK) cells. They play a role in intercellular communication by transporting signal molecules between the cells. Recent studies have reported that NK cell-derived exosomes (NK-exo) contain cytotoxic proteins-induced cell death. However, the characteristics and potential functions of NK-exo, especially for the liver cancer are poorly understood. In this study, we investigated the anti-tumor effects of NK-exo in the primary liver cancer, hepatocellular carcinoma (HCC), using the orthotopic and subcutaneous tumor model. We found that NK-exo expressed both typical exosomal markers (e.g. CD63, CD81, and Alix) and cytotoxic proteins (e.g. perforin, granzyme B, FasL, and TRAIL). NK-exo were selectively taken up by HCC cells (e.g. Hep3B, HepG2, and Huh 7). Interestingly, Hep3B cells induced the highest cytotoxicity compared with HepG2 and Huh7 cells, and substantially enhanced the apoptosis by NK-exo. Furthermore, we demonstrated that NK-exo inhibited the phosphorylation of serine/threonine protein kinases (e.g. AKT and ERK1/2), and enhanced the activation of specific apoptosis markers (e.g. caspase-3, -7, -8, -9, and PARP) in Hep3B cells. NK-exo also exhibit the active targeting ability and potent therapeutic effects in both orthotopic and subcutaneous HCC mouse models. Overall, these results suggest that NK-exo indicate strong anti-tumor effects in HCC, which are mediated by novel regulatory mechanisms involved in serine/threonine kinase pathway-associated cell proliferation and caspase activation pathway-associated apoptosis.

A 14-day-old female baby was admitted to the neonatal Intensive Care Unit (ICU) with complaints of fever for one week, along with reduced intake of feeds and weight loss. Routine investigations, blood culture, Cerebrospinal Fluid (CSF) routine analysis, and CSF culture were performed. Both cultures grew non typhoidal Salmonella enterica subspecies enterica. Magnetic Resonance Imaging (MRI) brain with contrast revealed leptomeningeal enhancement and basal exudates, both suggestive of meningitis, as well as ventriculitis and arachnoiditis. The baby was treated with intravenous Ceftriaxone and Meropenem. Follow-up CSF analysis showed improvement, and the cultures were sterile.

Abstract Cisplatin is effective against many types of carcinoma. However, a high rate of renal damage is a clinical problem. Thus, there is a need to establish a method to prevent it. Although various compounds have been reported to be effective against cisplatin‐induced renal injury, there are no examples of their clinical application. Therefore, we attempted to search for prophylactic agents with a high potential for clinical application. We used Cascade Eye to identify genes that are altered during cisplatin‐induced renal injury, Library of Integrated Network‐based Cellular Signatures (LINCS) to identify drugs that inhibit changes in gene expression, and a large database of spontaneous adverse drug reaction reports to identify drugs that could prevent cisplatin‐induced kidney injury in clinical practice. In total, 10 candidate drugs were identified. Using the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS), we identified drugs that reduce cisplatin‐induced kidney injury. Fenofibrate was selected as a candidate drug to prevent cisplatin‐induced kidney injury based on the FAERS analysis. A model was used to evaluate the efficacy of fenofibrate against cisplatin‐induced renal injury. Studies using HK2 cells and mouse models showed that fenofibrate significantly inhibited cisplatin‐induced renal injury but did not inhibit the antitumor effect of cisplatin. Fenofibrate is a candidate prophylactic drug with high clinical applicability for cisplatin‐induced renal injury. Analysis of data from multiple big databases will improve the search for novel prophylactic drugs with high clinical applicability. For the practical application of these findings, evaluation in prospective controlled trials is necessary.

The pressure field of a pulsating sphere is a canonical problem in classical acoustics, used to illustrate the acoustic efficiency of a monopole source at continuum conditions. We consider the counterpart vibroacoustic and thermoacoustic problems in a rarefied gas, to investigate the effect of continuum breakdown on monopole radiation. Focusing on small-amplitude normal-to-boundary mechanical and heat-flux excitations, the perturbation field is analysed in the entire range of gas rarefaction and input frequencies. Numerical calculations are carried out via the direct simulation Monte Carlo method, and are used to validate analytical predictions in the free-molecular and near-continuum regimes. In the latter, the regularized thirteen moments model (R13) is applied, to capture the system response at states where the Navier–Stokes–Fourier (NSF) description breaks down. Comparing with the continuum inviscid solution, the results quantitate the dampening effect of gas rarefaction on source point-wise strength and acoustic power. At near-continuum conditions, the acoustic field is composed of exponentially decaying 'compression', 'thermal' and 'Knudsen-layer' modes, reflecting thermoviscous and higher-order rarefaction effects. With reducing rarefaction, the contributions of the latter two modes vanish, and the former degenerates into the ideal-flow inverse-to-distance decaying wave. Stronger attenuation is obtained with increasing rarefaction, where boundary sphericity results in a 'geometric reduction' of the molecular layer affected by the source. Notably, while the R13 model at low frequencies appears valid up to moderate gas rarefaction rates, both the NSF and R13 descriptions break down at common low Knudsen numbers at higher frequencies. Further study should therefore be carried out to extend the applicability of moment models to unsteady flows with short time scales. [ABSTRACT FROM AUTHOR]

Abstract Nausea, vomiting, and renal injury are the common adverse effects associated with cisplatin. Cisplatin is excreted via the multidrug and toxin release (MATE) transporter, and the involvement of the MATE transporter in cisplatin‐induced kidney injury has been reported. The MATE transporter is also involved in the excretion of ondansetron, but the effects of 5‐HT3 receptor antagonists used clinically for cisplatin‐induced renal injury have not been elucidated. Therefore, the aim of this study was to investigate the effects of 5‐HT3 receptor antagonists in a mouse model of cisplatin‐induced kidney injury and to validate the results using medical big data analysis of more than 1.4 million reports and a survey of 3000 hospital medical records. The concomitant use of a first‐generation 5‐HT3 receptor antagonist (ondansetron, granisetron, or ramosetron) significantly increased cisplatin accumulation in the kidneys and worsened renal damage. Conversely, the concomitant use of palonosetron had no effect on renal function compared with the use of cisplatin alone. Furthermore, an analysis of data from the US Food and Drug Administration Adverse Event Reporting System and retrospective medical records revealed that the combination treatment of cisplatin and a first‐generation 5‐HT3 receptor antagonist significantly increased the number of reported renal adverse events compared with the combination treatment of cisplatin and a second‐generation 5‐HT3 receptor antagonist. These results suggest that compared with the first‐generation antagonists, second‐generation 5‐HT3 receptor antagonists do not worsen cisplatin‐induced acute kidney injury. The findings should be validated in a prospective controlled trial before implementation in clinical practice.

Abstract Background Skeletal muscle function is essential for health, and it depends on the proper activity of myofibers and their innervating motor neurons. Each adult muscle is composed of different types of myofibers with distinct contractile and metabolic characteristics. The proper balance of myofiber types is disrupted in most muscle degenerative disorders, representing another factor compromising muscle function. One promising therapeutic approach for the treatment of these diseases is cell replacement based on the targeted differentiation of pluripotent stem cells (PSCs) towards the myogenic lineage. We have previously shown that transient induction of Pax3 or Pax7 in PSCs allows for the generation of skeletal myogenic progenitors endowed with myogenic regenerative potential, but whether they contribute to different fiber types remains unknown. Results Here, we investigate the fiber type composition of mouse PSC-derived myofibers upon their transplantation into dystrophic and non-dystrophic mice. Our data reveal that PSC-derived myofibers express slow and oxidative myosin heavy-chain isoforms, along with developmental myosins, regardless of the recipient background. Furthermore, transplantation of the mononuclear cell fraction re-isolated from primary grafts into secondary recipients results in myofibers that maintain preferential expression of slow and oxidative myosin heavy-chain isoforms but no longer express developmental myosins, thus indicating postnatal composition. Conclusions Considering oxidative fibers are commonly spared in the context of dystrophic pathogenesis, this feature of PSC-derived myofibers could be advantageous for therapeutic applications.