Dengue virus (DENV) infection, the most common mosquito-transmitted viral infection, can cause a range of diseases from self-limiting dengue fever to life-threatening dengue hemorrhagic fever and ...shock syndrome. Thrombocytopenia is a major characteristic observed in both mild and severe dengue disease and is significantly correlated with the progression of dengue severity. Previous studies have shown that DENV nonstructural protein 1 (NS1), which can be secreted into patients' blood, can stimulate immune cells via Toll-like receptor 4 (TLR4) and can cause endothelial leakage. However, it is unclear whether DENV NS1 can directly induce platelet activation or cause thrombocytopenia during DENV infection. In this study, we first demonstrated that DENV but not Zika virus cell culture supernatant could induce P-selectin expression and phosphatidylserine (PS) exposure in human platelets, both of which were abolished when NS1 was depleted from the DENV supernatant. Similar results were found using recombinant NS1 from all four serotypes of DENV, and those effects were blocked in the presence of anti-NS1 F(ab')2, anti-TLR4 antibody, a TLR4 antagonist (Rhodobacter sphaeroides lipopolysaccharide, LPS-Rs) and a TLR4 signaling inhibitor (TAK242), but not polymyxin B (an LPS inhibitor). Moreover, the activation of platelets by DENV NS1 promoted subthreshold concentrations of adenosine diphosphate (ADP)-induced platelet aggregation and enhanced platelet adhesion to endothelial cells and phagocytosis by macrophages. Finally, we demonstrated that DENV-induced thrombocytopenia and hemorrhage were attenuated in TLR4 knockout and wild-type mice when NS1 was depleted from DENV supernatant. Taken together, these results suggest that the binding of DENV NS1 to TLR4 on platelets can trigger its activation, which may contribute to thrombocytopenia and hemorrhage during dengue infection.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Akt: a key transducer in cancer Tsai, Pei-Jane; Lai, Yi-Hsin; Manne, Rajesh Kumar ...
Journal of biomedical science,
10/2022, Volume:
29, Issue:
1
Journal Article
Peer reviewed
Open access
Growth factor signaling plays a pivotal role in diverse biological functions, such as cell growth, apoptosis, senescence, and migration and its deregulation has been linked to various human diseases. ...Akt kinase is a central player transmitting extracellular clues to various cellular compartments, in turn executing these biological processes. Since the discovery of Akt three decades ago, the tremendous progress towards identifying its upstream regulators and downstream effectors and its roles in cancer has been made, offering novel paradigms and therapeutic strategies for targeting human diseases and cancers with deregulated Akt activation. Unraveling the molecular mechanisms for Akt signaling networks paves the way for developing selective inhibitors targeting Akt and its signaling regulation for the management of human diseases including cancer.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Clostridium difficile infections (CDIs) cause significant mortality and morbidity. Critically ill patients are susceptible to CDIs and tend to have severe CDIs, and their clinical presentations are ...not merely diarrhea.
From September 2017 to March 2018, the adults with CDIs in the ICUs were included. Fecal specimens with positive results of glutamate dehydrogenase assay were cultured for C. difficile, and toxinotyping and ribotyping for available C. difficile isolates were done. The CDI cases were categorized into the diarrheal group and ileus group. Difficult-to-treat cases with the presentations of life-threatening complications (bowel perforation or bacteremia), toxic megacolon, and refractory diarrhea, were analyzed.
Totally 23 cases, including 6 cases of ileus and 17 of diarrhea, were included. Overall, the incidence of CDI in the ICUs was 10.7 cases per 10,000 patient-days. The ileus group tended to have more severe presentation, shorter ICU stay, higher ICU mortality, and receive initial intravenous metronidazole therapy. Severe and fulminant CDIs accounted for 65.2% (15 cases). The ICU mortality rate was 39.1%, but only one death was directly related to CDI (4.3%). Of nine (39.1%) difficult-to-treat cases, there was only one isolate of RT611 with tcdC deletion and cdtA/cdtB from a case with toxic megacolon. No hypervirulent isolates of RT027 or 078 were detected.
Severe CDIs in the ICU were not rare. Clinicians should be aware of abdominal symptoms and signs other than diarrhea, such as ileus, to make timely diagnosis and management of CDI.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Clostridioides difficile is the leading cause of nosocomial infectious diarrhea, with clinical symptoms ranging from mild diarrhea to pseudomembranous colitis and toxic megacolon. Despite the use of ...vancomycin and fidaxomicin as standard drugs for the treatment of C. difficileinfection (CDI), clinical relapse rates remain high. Therefore, new alternative therapeutics to treat CDI are urgently required. Surface layer proteins (SLPs) are the most abundant proteins in the C. difficile cell wall, suggesting that they might involve in immune recognition. Here, we found SLPs as well as C. difficile induced inflammasome activation. In addition, the cholesterol‐rich microdomains, lipid rafts, on the cell membrane are thought to be crucial for bacterial adhesion and signal transduction. We demonstrated that lipid rafts participated in C. difficile SLPs binding to the cell membrane. Furthermore, both binding ability and inflammasome activation induced by SLP were abrogated with membrane cholesterol depletion by methyl‐β‐cyclodextrin (MβCD). The coalescence of SLPs in the cholesterol‐rich microdomains was confirmed in C. difficile‐infected cells. Our results demonstrate that SLPs recruit the lipid rafts, which may be a key step for C. difficile colonization and inducing inflammasome activation.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A photokilling approach for pathogenic bacteria is demonstrated using a new type of magnetic nanoprobe as the photokilling agent. In addition to their magnetic property, the nanoprobes have other ...features including a photocatalytic property and the capacity to target bacteria. The nanoprobes comprise iron oxide/titania (Fe3O4@TiO2) core/shell magnetic nanoparticles. As dopamine molecules can self‐assemble onto the surface of the titania substrate, dopamine is used as the linker to immobilize succinic anhydride onto the surfaces of the Fe3O4@TiO2 nanoparticles. This is followed by the immobilization of IgG via amide bonding. We demonstrate that the IgGFe3O4@TiO2 magnetic nanoparticles not only have the capacity to target several pathogenic bacteria, but they also can effectively inhibit the cell growth of the bacteria targeted by the nanoparticles under irradiation of a low‐power UV lamp within a short period. Staphylococcus saprophyticus, Streptococcus pyogenes, and antibiotic‐resistant bacterial strains, such as multiantibiotic‐resistant S. pyogenes and methicillin‐resistant Staphylococcus aureus (MRSA), are used to demonstrate the feasibility of this approach.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Stimulation of the NLRP3 inflammasome by metabolic byproducts is known to result in inflammatory responses and metabolic diseases. However, how the host controls aberrant NLRP3 inflammasome ...activation remains unclear. PPARγ, a known regulator of energy metabolism, plays an anti-inflammatory role through the inhibition of NF-κB activation and additionally attenuates NLRP3-dependent IL-1β and IL-18 production. Therefore, we hypothesized that PPARγ serves as an endogenous modulator that attenuates NLRP3 inflammasome activation in macrophages.
Mouse peritoneal macrophages with exposure to a PPARγ agonist at different stages and the NLRP3 inflammasome-reconstituted system in HEK293T cells were used to investigate the additional anti-inflammatory effect of PPARγ on NLRP3 inflammasome regulation. Circulating mononuclear cells of obese patients with weight-loss surgery were used to identify the
correlation between PPARγ and the NLRP3 inflammasome.
Exposure to the PPARγ agonist, rosiglitazone, during the second signal of NLRP3 inflammasome activation attenuated caspase-1 and IL-1β maturation. Moreover, PPARγ interfered with NLRP3 inflammasome formation by decreasing NLRP3-ASC and NLRP3-NLRP3 interactions as well as NLRP3-dependent ASC oligomerization, which is mediated through interaction between the PPARγ DNA-binding domain and the nucleotide-binding and leucine-rich repeat domains of NLRP3. Furthermore, PPARγ was required to limit metabolic damage-associated molecular pattern-induced NLRP3 inflammasome activation in mouse macrophages. Finally, the mature caspase-1/PPARγ ratio was reduced in circulating mononuclear cells of obese patients after weight-loss surgery, which we define as an "NLRP3 accelerating index".
These results revealed an additional anti-inflammatory role for PPARγ in suppressing NLRP3 inflammasome activation through interaction with NLRP3. Thus, our study highlights that PPARγ agonism may be a therapeutic option for targeting NLRP3-related metabolic diseases.
Emerging advances in iron oxide nanoparticles exploit their high magnetization for various applications, such as bioseparation, hyperthermia, and magnetic resonance imaging. In contrast to their ...excellent magnetic performance, the harmonic generation and luminescence properties of iron oxide nanoparticles have not been thoroughly explored, thus limiting their development as a tool in photomedicine. In this work, a seed/growth‐inspired synthesis is developed combined with primary mineralization and a ligand‐assisted secondary growth strategy to prepare mesostructured α‐FeOOH nanorods (NRs). The sub‐wavelength heterogeneity of the refractive index leads to enhanced third‐harmonic generation (THG) signals under near‐infrared excited wavelengths at 1230 nm. The as‐prepared NRs exhibit an 11‐fold stronger THG intensity compared to bare α‐FeOOH NRs. Using these unique nonlinear optical properties, it is demonstrated that mesostructured α‐FeOOH NRs can serve as biocompatible and nonbleaching contrast agents in THG microscopy for long‐term labeling of cells as well as in angiography in vivo by modifying lectin to enhance the binding efficiency to the glycocalyx layers on the wall of blood vessels. These results provide a new insight into Fe‐based nanoplatforms capable of emitting coherent light as molecular probes in optical microscopy, thus establishing a complementary microscopic imaging method for macroscopic magnetic imaging systems.
Demonstrated is the novel synthesis method of time‐dependent mesostructured α‐FeOOH nanorods through a template‐assisted Ostwald ripening process that exhibits low cytotoxicity and enhances harmonic generation and luminescence signals at 410 nm upon near‐infrared II excitation of 1230 nm for the evaluation of cellular internalization in vitro and angiography in vivo in a mouse ear.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
In many human cancers, including hepatocellular carcinoma (HCC), high density of infiltrating tumor-associated macrophages (TAM) is associated with poor prognosis. Most TAMs express a M2 phenotype ...subsequently supporting tumor growth. How tumor cells polarize these TAMs to a pro-tumor M2 phenotype is still poorly understood. Our previous studies have revealed that a Toll-like receptor 2 (TLR2)-dependent autophagy triggered by hepatoma-derived factors down-regulates NF-κB p65 and drives M2 macrophage differentiation. However, the underlying mechanisms and potential hepatoma-derived TLR2 ligands are not clear. Here, we provide evidence to reveal that NADPH oxidase 2 (NOX2)-dependent reactive oxygen species (ROS) generation is crucial for HCC-induced autophagy, NF-κB p65 down-regulation and M2 phenotype polarization in primary macrophages. This NOX2-generated ROS production in abolished in TLR2-deficient macrophages. HCC-derived or recombinant high-mobility group box 1 (HMGB1) is able to trigger this TLR2-mediated M2 macrophage polarization. Blockage of HMGB1 and ROS by inhibitors, ethyl pyruvate and N-acetylcysteine amide, respectively, significantly reduces both M2 macrophage accumulation and liver nodule formation in HCC-bearing mice. Our findings uncover a HMGB1/TLR2/NOX2/autophagy axis to trigger M2 macrophage polarization in HCC that can be considered as a novel therapeutic target for treating HCC.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Abstract
Clostridioides difficile
spores are considered as the major source responsible for the development of
C
.
difficile
infection (CDI), which is associated with an increased risk of death in ...patients and has become an important issue in infection control of nosocomial infections. Current treatment against CDI still relies on antibiotics, which also damage normal flora and increase the risk of CDI recurrence. Therefore, alternative therapies that are more effective against
C
.
difficile
bacteria and spores are urgently needed. Here, we designed an oxidation process using H
2
O
2
containing PBS solution to generate Cl
−
and peroxide molecules that further process Ag and Au ions to form nanoboxes with Ag–Au peroxide coat covering Au shell and AgCl core (AgAu‐based nanoboxes). The AgAu‐based nanoboxes efficiently disrupted the membrane structure of bacteria/spores of
C
.
difficile
after 30–45 min exposure to the highly reactive Ag/Au peroxide surface of the nano structures. The Au‐enclosed AgCl provided sustained suppression of the growth of 2 × 10
7
pathogenic
Escherichia coli
for up to 19 days. In a fecal bench ex vivo test and in vivo CDI murine model, biocompatibility and therapeutic efficacy of the AuAg nanoboxes to attenuate CDI was demonstrated by restoring the gut microbiota and colon mucosal structure. The treatment successfully rescued the CDI mice from death and prevented their recurrence mediated by vancomycin treatment. The significant outcomes indicated that the new peroxide‐derived AgAu‐based nanoboxes possess great potential for future translation into clinical application as a new alternative therapeutic strategy against CDI.
Full text
Available for:
FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
PDF
