Hepatocyte Intrinsic Innate Antiviral Immunity against Hepatitis Delta Virus Infection: The Voices of Bona Fide Human Hepatocytes.

The pathogenesis of viral infection is attributed to two folds: intrinsic cell death pathway activation due to the viral cytopathic effect, and immune-mediated extrinsic cellular injuries. The immune system, encompassing both innate and adaptive immunity, therefore acts as a double-edged sword in viral infection. Insufficient potency permits pathogens to establish lifelong persistent infection and its consequences, while excessive activation leads to organ damage beyond its mission to control viral pathogens. The innate immune response serves as the front line of defense against viral infection, which is triggered through the recognition of viral products, referred to as pathogen-associated molecular patterns (PAMPs), by host cell pattern recognition receptors (PRRs). The PRRs-PAMPs interaction results in the induction of interferon-stimulated genes (ISGs) in infected cells, as well as the secretion of interferons (IFNs), to establish a tissue-wide antiviral state in an autocrine and paracrine manner. Cumulative evidence suggests significant variability in the expression patterns of PRRs, the induction potency of ISGs and IFNs, and the IFN response across different cell types and species. Hence, in our understanding of viral hepatitis pathogenesis, insights gained through hepatoma cell lines or murine-based experimental systems are uncertain in precisely recapitulating the innate antiviral response of genuine human hepatocytes. Accordingly, this review article aims to extract and summarize evidence made possible with bona fide human hepatocytes-based study tools, along with their clinical relevance and implications, as well as to identify the remaining gaps in knowledge for future investigations.

Injectable Extracellular Matrix-Inspired Hemostatic Hydrogel Composed of Hyaluronan and Gelatin with Shear-Thinning and Self-Healing.

Injectable ECM-inspired hydrogels composed of hyaluronic acid and gelatin are biocompatible and potentially useful for various medical applications. We developed injectable hydrogels composed of monoaldehyde-modified hyaluronic acid (HA-mCHO) and carbohydrazide-modified gelatin (GL-CDH), "HA/GL gel", whose ratios of HA-mCHO to GL-CDH were different. The hydrogels exhibited gelation times shorter than 3 s. In addition, the hydrogels showed strong shear-thinning and self-healing properties, mainly because of the dynamic covalent bonding of Schiff bases between HA-mCHO and GL-CDH. This hydrogel degraded in the mice's peritoneum for a week and showed excellent biocompatibility. Moreover, the hydrogel showed a higher breaking strength than fibrin glue in the lap shear test of porcine skin. Finally, the hydrogels decreased bleeding to as low as fibrin glue without using thrombin and fibrinogen in a mouse liver bleeding model in both single- and double-barreled syringe administrations. HA/GL gels have the potential for excellent biocompatibility and hemostasis in clinical settings.

VEGF-A165 is the predominant VEGF-A isoform in platelets, while VEGF-A121 is abundant in serum and plasma from healthy individuals.

Vascular endothelial growth factor A (VEGF-A) plays pivotal roles in regulating tumor angiogenesis as well as physiological vascular function. The major VEGF-A isoforms, VEGF-A121 and VEGF-A165, in serum, plasma, and platelets have not been exactly evaluated due to the lack of the appropriate assay system. Antibodies against human VEGF-A121 and VEGF-A165 (hVEGF-A121 and hVEGF-A165) were successfully produced and Enzyme-Linked ImmunoSorbent Assay (ELISA) for hVEGF-A121 and hVEGF-A165 were separately created by these monoclonal antibodies. The measurement of recombinant hVEGF-A121 and hVEGF-A165 by the created ELISA showed no cross-reaction between hVEGF-A121 and hVEGF-A165 in conditioned media from HEK293 cells transfected with either hVEGF-A121 or hVEGF-A165 expression vector. The levels of VEGF-A121 and VEGF-A165 in serum, plasma, and platelets from 59 healthy volunteers proved that VEGF-A121 level was higher than VEGF-A165 in both plasma and serum in all the cases. VEGF-A121 or VEGF-A165 in serum represented higher level than that in plasma. In contrast, the level of VEGF-A165 was higher than VEGF-A121 in platelets. The newly developed ELISAs for hVEGF-A121 and hVEGF-A165 revealed different ratios of VEGF isoforms in serum, plasma, and platelets. Measuring these isoforms in combination provides useful information as biomarkers for diseases involving VEGF-A121 and VEGF-A165.

Dynamic changes in platelets caused by shear stress in aortic valve stenosis.

BACKGROUND AND OBJECTIVE: Turbulent blood flow in patients with aortic valve stenosis (AS) results in morphological and functional changes in platelets and coagulation factors. The aim of this study is to determine how shear stress affects platelets and coagulation factors. METHODS: We retrospectively evaluated data from 78 patients who underwent AVR to treat AS between March 2008 and July 2017 at Kagoshima University Hospital. RESULTS: Platelet (PLT) count obviously decreased at three days after AVR, and increased above preoperative levels at the time of discharge. In contrast, platelet distribution width (PDW), mean platelet volume (MPV), and platelet large cell ratio (P-LCR) increased three days after AVR, then decreased to below preoperative levels. No differences were evident between groups with higher (HPPG > 100 mmHg) and lower (LPPG < 100 mmHg) peak pressure gradients (PPG) before AVR, whereas PLT count, PDW, MPV and P-LCR improved more in the HPPG group. Plateletcrit (PCT), which represents the total volume of platelets, increased after AVR due to decreased shear stress. High increasing rate of PCT was associated with lower PLT count, higher PDW and lower fibrinogen. CONCLUSION: Shear stress affects PLT count, PDW, and fibrinogen in patients with AS.

The Balance between the Hemostatic Effect and Immune Response of Hyaluronan Conjugated with Different Chain Lengths of Inorganic Polyphosphate.

Inorganic polyphosphate (PolyP) is a potential hemostatic material. However, the effect of PolyP chain length on the immune response and hemostatic function remains to be established. We have developed PolyP-conjugated hyaluronans (HA-PolyPs) with three different short-chain PolyPs (n = 13, 40, and 100 phosphate units). All short-chain PolyPs showed biocompatibility in the cell viability and inflammatory cytokine secretion test in vitro and in vivo, wherein shorter PolyPs showed milder responses in some cases. We then produced HA-PolyP hydrogels (HAX-PolyPs) with three different short-chain PolyPs as hemostats. Interestingly, the in vivo biocompatibility and hemostatic activity of HAX-PolyP were not significantly affected by the length of conjugated PolyPs. HAX-PolyP with all chain lengths significantly decreased the amount of bleeding in a novel mouse liver bleeding model. These results indicated that the shortest PolyP (n = 13) induced milder acute inflammation and had an efficient hemostatic effect when conjugated to hyaluronic acid. The present study provides key insights into the design of PolyP-based biomaterials and bioconjugates, which are expected to grow in importance for various medical applications.

Tributyltin-induced Ca(2+) mobilization via L-type voltage-dependent Ca(2+) channels in PC12 cells.

The effects of tributyltin (TBT) on cytosolic Ca(2+) concentration ([Ca(2+)](c)) and cell viability were investigated in nerve growth factor-differentiated PC12 cells. TBT concentration dependently increased [Ca(2+)](c) with an EC(50) value of 0.07µM. This effect was markedly reduced by removal of the extracellular Ca(2+) or membrane depolarization with a high K(+) medium, but unaffected by thapsigargin causing depletion of intracellular Ca(2+) stores. The L-type voltage-dependent Ca(2+) channel (VDCC) blocker nicardipine blocked the effect of TBT, but the N-type VDCC blocker ω-conotoxin did not. TBT decreased the number of viable cells with an EC(50) value of 0.09µM. The TBT-induced cell death was prevented by nicardipine or by chelating the cytosolic Ca(2+) with BAPTA-AM, but not by ω-conotoxin. The results show that TBT causes an increase in [Ca(2+)](c) via activating L-type VDCCs, and support the idea that the organotin-induced cell death arises through Ca(2+) mobilization via L-type VDCCs.