Peptidic heterodimer-based radiotracer targeting fibroblast activation protein and integrin αvß3.

PURPOSE: Several studies have demonstrated the advantages of heterodimers over their corresponding monomers due to the multivalency effect. This effect leads to an increased number of effective targeted receptors and, consequently, improved tumor uptake. Fibroblast activation protein (FAP) and integrin αvß3 are found to be overexpressed in different components of the tumor microenvironment. In our pursuit of enhancing tumor uptake and retention, we designed and developed a novel peptidic heterodimer that synergistically targets both FAP and integrin αvß3. METHODS: FAP-RGD was synthesized from FAP-2286 and c(RGDfK) through a multi-step organic synthesis. The dual receptor binding property of 68Ga-FAP-RGD was investigated by cell uptake and competitive binding assays. Preclinical pharmacokinetics were determined in HT1080-FAP and U87MG tumor models using micro-positron emission tomography/computed tomography (micro-PET/CT) and biodistribution studies. The antitumor efficacy of 177Lu-FAP-RGD was assessed in U87MG tumor models. The radiation exposure and clinical diagnostic performance of 68 Ga-FAP-RGD were evaluated in healthy volunteers and cancer patients. RESULTS: Bi-specific radiotracer 68Ga-FAP-RGD exhibited high binding affinity for both FAP and integrin αvß3. In comparison to 68Ga-FAP-2286 and 68Ga-RGDfK, 68Ga-FAP-RGD displayed enhanced tumor uptake and longer tumor retention time in preclinical models. 177Lu-FAP-RGD could efficiently suppress the growth of U87MG tumor in vivo when applied at an activity of 18.5 and 29.6 MBq. The effective dose of 68Ga-FAP-RGD was 1.06 × 10-2 mSv/MBq. 68Ga-FAP-RGD demonstrated low background activity and stable accumulation in most neoplastic lesions up to 3 h. CONCLUSION: Taking the advantages of multivalency effect, the bi-specific radiotracer 68Ga-FAP-RGD showed superior tumor uptake and retention compared to its corresponding monomers. Preclinical studies with 68Ga- or 177Lu-labeled FAP-RGD showed favorable image contrast and effective antitumor responses. Despite the excellent performance of 68Ga-FAP-RGD in clinical diagnosis, experimental efforts are currently underway to optimize the structure of FAP-RGD to increase its potential for clinical application in endoradiotherapy.

PI3-Kinase-γ Has a Distinct and Essential Role in Lung-Specific Dendritic Cell Development.

Development of dendritic cells (DCs) commences in the bone marrow, from where pre-DCs migrate to peripheral organs to differentiate into mature DCs in situ. However, the factors that regulate organ-specific differentiation to give rise to tissue-specific DC subsets remain unclear. Here we show that the Ras-PI3Kγ-Akt-mTOR signaling axis acted downstream of FLT3L signaling and was required for development of lung CD103(+) DCs and, to a smaller extent, for lung CD11b(+) DCs, but not related DC populations in other non-lymphoid organs. Furthermore, we show that in lymphoid organs such as the spleen, DCs depended on a similar signaling network to respond to FLT3 ligand with overlapping and partially redundant roles for kinases PI3Kγ and PI3Kδ. Thus we identified PI3Kγ as an essential organ-specific regulator of lung DC development and discovered a signaling network regulating tissue-specific DC development mediated by FLT3.

A role for Sfrp2 in cardiomyogenesis in vivo.

Cardiomyogenesis, the process by which the body generates cardiomyocytes, is poorly understood. We have recently shown that Sfrp2 promotes cardiomyogenesis in vitro. The objective of this study was to determine if Sfrp2 would similarly promote cardiomyogenesis in vivo. To test this hypothesis, we tracked multipotent cKit(+) cells in response to Sfrp2 treatment. In control adult mice, multipotent cKit(+) cells typically differentiated into endothelial cells but not cardiomyocytes. In contrast, Sfrp2 switched the fate of these cells. Following Sfrp2 injection, multipotent cKit(+) cells differentiated solely into cardiomyocytes. Sfrp2-derived cardiomyocytes integrated into the myocardium and exhibited identical physiological properties to preexisting native cardiomyocytes. The ability of Sfrp2 to promote cardiomyogenesis was further supported by tracking EdU-labeled cells. In addition, Sfrp2 did not promote the formation of new cardiomyocytes when the cKit(+) cell population was selectively ablated in vivo using a diphtheria toxin receptor-diphtheria toxin model. Notably, Sfrp2-induced cardiomyogenesis was associated with significant functional improvements in a cardiac injury model. In summary, our study further demonstrates the importance of Sfrp2 in cardiomyogenesis.

Soluble mannose receptor induces proinflammatory macrophage activation and metaflammation.

Proinflammatory activation of macrophages in metabolic tissues is critically important in the induction of obesity-induced metaflammation. Here, we demonstrate that the soluble mannose receptor (sMR) plays a direct functional role in both macrophage activation and metaflammation. We show that sMR binds CD45 on macrophages and inhibits its phosphatase activity, leading to an Src/Akt/NF-κB-mediated cellular reprogramming toward an inflammatory phenotype both in vitro and in vivo. Remarkably, increased serum sMR levels were observed in obese mice and humans and directly correlated with body weight. Importantly, enhanced sMR levels increase serum proinflammatory cytokines, activate tissue macrophages, and promote insulin resistance. Altogether, our results reveal sMR as regulator of proinflammatory macrophage activation, which could constitute a therapeutic target for metaflammation and other hyperinflammatory diseases.

Activation of mouse Otop3 proton channels by Zn2.

Otopetrins (Otop1-Otop3) belong to a newly identified family of proton (H+) channels activated by extracellular acidification. Here, we found that Zn2+ activates the mouse Otop3 (mOtop3) proton channels by using electrophysiological patch-clamp techniques. In mOtop3-expressing human embryonic kidney HEK293T cells, a biphasic inward mOtop3 H+ current comprising a fast transient current followed by a sustained current was observed upon extracellular acidification at pH 5.0. No significant activation of the mOtop3 channel was observed at pH 6.5 and 7.4, but interestingly, Zn2+ dose-dependently induced a sustained activation of mOtop3 under these pH conditions. Increasing the Zn2+ concentration had no effect on the reversal potential of the channel currents, suggesting that Zn2+ does not permeate through the mOtop3. The activation of the mOtop3 channel was specific to Zn2+ among divalent metal cations. Our findings reveal a novel modulatory mechanism of mOtop3 proton channels by Zn2+.

STING agonist delivery by tumour-penetrating PEG-lipid nanodiscs primes robust anticancer immunity.

Activation of the innate immune STimulator of INterferon Genes (STING) pathway potentiates antitumour immunity, but systemic delivery of STING agonists to tumours is challenging. We conjugated STING-activating cyclic dinucleotides (CDNs) to PEGylated lipids (CDN-PEG-lipids; PEG, polyethylene glycol) via a cleavable linker and incorporated them into lipid nanodiscs (LNDs), which are discoid nanoparticles formed by self-assembly. Compared to state-of-the-art liposomes, intravenously administered LNDs carrying CDN-PEG-lipid (LND-CDNs) exhibited more efficient penetration of tumours, exposing the majority of tumour cells to STING agonist. A single dose of LND-CDNs induced rejection of established tumours, coincident with immune memory against tumour rechallenge. Although CDNs were not directly tumoricidal, LND-CDN uptake by cancer cells correlated with robust T-cell activation by promoting CDN and tumour antigen co-localization in dendritic cells. LNDs thus appear promising as a vehicle for robust delivery of compounds throughout solid tumours, which can be exploited for enhanced immunotherapy.

Cannabinoid exposure in rat adolescence reprograms the initial behavioral, molecular, and epigenetic response to cocaine.

The initial response to an addictive substance can facilitate repeated use: That is, individuals experiencing more positive effects are more likely to use that drug again. Increasing evidence suggests that psychoactive cannabinoid use in adolescence enhances the behavioral effects of cocaine. However, despite the behavioral data, there is no neurobiological evidence demonstrating that cannabinoids can also alter the brain's initial molecular and epigenetic response to cocaine. Here, we utilized a multiomics approach (epigenomics, transcriptomics, proteomics, and phosphoproteomics) to characterize how the rat brain responds to its first encounter with cocaine, with or without preexposure to the synthetic cannabinoid WIN 55,212-2 (WIN). We find that in adolescent (but not in adult) rats, preexposure to WIN results in cross-sensitization to cocaine, which correlates with histone hyperacetylation and decreased levels of HDAC6 in the prefrontal cortex (PFC). In the PFC, we also find that WIN preexposure blunts the typical mRNA response to cocaine and instead results in alternative splicing and chromatin accessibility events, involving genes such as Npas2 Moreover, preexposure to WIN enhances the effects of cocaine on protein phosphorylation, including ERK/MAPK-targets like gephyrin, and modulates the synaptic AMPAR/GluR composition both in the PFC and the nucleus accumbens (NAcc). PFC-NAcc gene network topological analyses, following cocaine exposure, reveal distinct top nodes in the WIN preexposed group, which include PACAP/ADCYAP1. These preclinical data demonstrate that adolescent cannabinoid exposure reprograms the initial behavioral, molecular, and epigenetic response to cocaine.

Phospholemman Phosphorylation Regulates Vascular Tone, Blood Pressure, and Hypertension in Mice and Humans.

BACKGROUND: Although it has long been recognized that smooth muscle Na/K ATPase modulates vascular tone and blood pressure (BP), the role of its accessory protein phospholemman has not been characterized. The aim of this study was to test the hypothesis that phospholemman phosphorylation regulates vascular tone in vitro and that this mechanism plays an important role in modulation of vascular function and BP in experimental models in vivo and in humans. METHODS: In mouse studies, phospholemman knock-in mice (PLM3SA; phospholemman [FXYD1] in which the 3 phosphorylation sites on serines 63, 68, and 69 are mutated to alanines), in which phospholemman is rendered unphosphorylatable, were used to assess the role of phospholemman phosphorylation in vitro in aortic and mesenteric vessels using wire myography and membrane potential measurements. In vivo BP and regional blood flow were assessed using Doppler flow and telemetry in young (14-16 weeks) and old (57-60 weeks) wild-type and transgenic mice. In human studies, we searched human genomic databases for mutations in phospholemman in the region of the phosphorylation sites and performed analyses within 2 human data cohorts (UK Biobank and GoDARTS [Genetics of Diabetes Audit and Research in Tayside]) to assess the impact of an identified single nucleotide polymorphism on BP. This single nucleotide polymorphism was expressed in human embryonic kidney cells, and its effect on phospholemman phosphorylation was determined using Western blotting. RESULTS: Phospholemman phosphorylation at Ser63 and Ser68 limited vascular constriction in response to phenylephrine. This effect was blocked by ouabain. Prevention of phospholemman phosphorylation in the PLM3SA mouse profoundly enhanced vascular responses to phenylephrine both in vitro and in vivo. In aging wild-type mice, phospholemman was hypophosphorylated, and this correlated with the development of aging-induced essential hypertension. In humans, we identified a nonsynonymous coding variant, single nucleotide polymorphism rs61753924, which causes the substitution R70C in phospholemman. In human embryonic kidney cells, the R70C mutation prevented phospholemman phosphorylation at Ser68. This variant's rare allele is significantly associated with increased BP in middle-aged men. CONCLUSIONS: These studies demonstrate the importance of phospholemman phosphorylation in the regulation of vascular tone and BP and suggest a novel mechanism, and therapeutic target, for aging-induced essential hypertension in humans.

Rho-of-plant activated root hair formation requires Arabidopsis YIP4a/b gene function.

Root hairs are protrusions from root epidermal cells with crucial roles in plant soil interactions. Although much is known about patterning, polarity and tip growth of root hairs, contributions of membrane trafficking to hair initiation remain poorly understood. Here, we demonstrate that the trans-Golgi network-localized YPT-INTERACTING PROTEIN 4a and YPT-INTERACTING PROTEIN 4b (YIP4a/b) contribute to activation and plasma membrane accumulation of Rho-of-plant (ROP) small GTPases during hair initiation, identifying YIP4a/b as central trafficking components in ROP-dependent root hair formation.

Bulleyaconitine A is a sensitive substrate and competitive inhibitor of CYP3A4: One of the possible explanations for clinical adverse reactions.

Bulleyaconitine A (BLA), a toxic Aconitum alkaloid, is a potent analgesic that is clinically applied to treat rheumatoid arthritis, osteoarthritis and lumbosacral pain. BLA-related adverse reactions occur frequently, but whether the underlying mechanism is related to its metabolic interplay with drug-metabolizing enzymes remains unclear. This study aimed to elucidate the metabolic characteristics of BLA and its affinity action and mechanism to drug-metabolizing enzymes to reveal whether BLA-related adverse reactions are modulated by enzymes. After incubation with human liver microsomes and recombinant human cytochrome P450 enzymes, we found that BLA was predominantly metabolized by CYP3A, in which CYP3A4 had an almost absolute advantage. In vitro, the CYP3A4 inhibitor ketoconazole noticeably suppressed the metabolism of BLA. In vivo, the AUC0-∞ values, cardiotoxicity and neurotoxicity of BLA in Cyp3a-inhibited mice were all obviously enhanced (P < 0.05) compared to those in normal mice. In the enzyme kinetics study, BLA was found to be a sensitive substrate of CYP3A4, and its characteristics were consistent with substrate inhibition (Km = 39.36 ± 10.47 µmol/L, Ks = 83.42 ± 19.65 µmol/L). BLA was further identified to be a competitive inhibitor of CYP3A4 with Ki = 53.64 µmol/L, since the intrinsic clearance (CLint) of midazolam, a selective CYP3A4 substrate, decreased significantly (P < 0.05) when incubated with BLA together in mouse liver microsomes. Overall, BLA is a sensitive substrate and competitive inhibitor of CYP3A4, and clinical adverse reactions of BLA may mechanistically related to the CYP3A4-mediated drug-drug interactions.

LRRC52 regulates BK channel function and localization in mouse cochlear inner hair cells.

The perception of sound relies on sensory hair cells in the cochlea that convert the mechanical energy of sound into release of glutamate onto postsynaptic auditory nerve fibers. The hair cell receptor potential regulates the strength of synaptic transmission and is shaped by a variety of voltage-dependent conductances. Among these conductances, the Ca2+- and voltage-activated large conductance Ca2+-activated K+ channel (BK) current is prominent, and in mammalian inner hair cells (IHCs) displays unusual properties. First, BK currents activate at unprecedentedly negative membrane potentials (-60 mV) even in the absence of intracellular Ca2+ elevations. Second, BK channels are positioned in clusters away from the voltage-dependent Ca2+ channels that mediate glutamate release from IHCs. Here, we test the contributions of two recently identified leucine-rich-repeat-containing (LRRC) regulatory γ subunits, LRRC26 and LRRC52, to BK channel function and localization in mouse IHCs. Whereas BK currents and channel localization were unaltered in IHCs from Lrrc26 knockout (KO) mice, BK current activation was shifted more than +200 mV in IHCs from Lrrc52 KO mice. Furthermore, the absence of LRRC52 disrupted BK channel localization in the IHCs. Given that heterologous coexpression of LRRC52 with BK α subunits shifts BK current gating about -90 mV, to account for the profound change in BK activation range caused by removal of LRRC52, we suggest that additional factors may help define the IHC BK gating range. LRRC52, through stabilization of a macromolecular complex, may help retain some other components essential both for activation of BK currents at negative membrane potentials and for appropriate BK channel positioning.

Identification of Bacterial Membrane Selectivity of Romo1-Derived Antimicrobial Peptide AMPR-22 via Molecular Dynamics.

The abuse or misuse of antibiotics has caused the emergence of extensively drug-resistant (XDR) bacteria, rendering most antibiotics ineffective and increasing the mortality rate of patients with bacteremia or sepsis. Antimicrobial peptides (AMPs) are proposed to overcome this problem; however, many AMPs have attenuated antimicrobial activities with hemolytic toxicity in blood. Recently, AMPR-11 and its optimized derivative, AMPR-22, were reported to be potential candidates for the treatment of sepsis with a broad spectrum of antimicrobial activity and low hemolytic toxicity. Here, we performed molecular dynamics (MD) simulations to clarify the mechanism of lower hemolytic toxicity and higher efficacy of AMPR-22 at an atomic level. We found four polar residues in AMPR-11 bound to a model mimicking the bacterial inner/outer membranes preferentially over eukaryotic plasma membrane. AMPR-22 whose polar residues were replaced by lysine showed a 2-fold enhanced binding affinity to the bacterial membrane by interacting with bacterial specific lipids (lipid A or cardiolipin) via hydrogen bonds. The MD simulations were confirmed experimentally in models that partially mimic bacteremia conditions in vitro and ex vivo. The present study demonstrates why AMPR-22 showed low hemolytic toxicity and this approach using an MD simulation would be helpful in the development of AMPs.

An Interleukin-4 and Interleukin-13 Induced Atopic Dermatitis Human Skin Equivalent Model by a Skin-On-A-Chip.

Currently, the mechanism of progression of atopic dermatitis (AD) is not well understood because there is no physiologically appropriate disease model in terms of disease complexity and multifactoriality. Type 2 inflammation, mediated by interleukin (IL)-4 and IL-13, plays an important role in AD. In this study, full-thickness human skin equivalents consisting of human-derived cells were fabricated from pumpless microfluidic chips and stimulated with IL-4 and IL-13. The morphological properties, gene expression, cytokine secretion and protein expression of the stimulated human skin equivalent (HSE) epidermis were investigated. The results showed epidermal and spongy formations similar to those observed in lesions in AD, and decreased expression of barrier-related filaggrin, loricrin and involucrin genes and proteins induced by IL-4Rα signaling. In addition, we induced the expression of carbonic anhydrase II (CAII), a gene specifically expressed in the epidermis of patients with AD. Thus, AD human skin equivalents can be used to mimic the key pathological features of atopic dermatitis, overcoming the limitations of existing studies that rely solely on mouse models and have been unable to translate their effects to humans. Our results will be useful for future research on the development of therapeutic agents for atopic dermatitis.

MG53 inhibits angiogenesis through regulating focal adhesion kinase signalling.

Mitsugumin 53 (MG53), which is expressed predominantly in striated muscle, has been demonstrated to be a myokine/cardiokine secreted from striated muscle under specific conditions. The important roles of MG53 in non-striated muscle tissues have also been examined in multiple disease models. However, no previous study has implicated MG53 in the control of endothelial cell function. In order to explore the effects of MG53 on endothelial cells, human umbilical vein endothelial cells (HUVECs) were stimulated with recombinant human MG53 (rhMG53). Then, rhMG53 uptake, focal adhesion kinase (FAK)/Src/Akt/ERK1/2 signalling pathway activation, cell migration and tube formation were determined in vitro. The efficacy of rhMG53 in regulating angiogenesis was also detected in postnatal mouse retinas. The results demonstrated that rhMG53 directly entered into endothelial cells in a cholesterol-dependent manner. The uptake of rhMG53 directly bound to FAK in endothelial cells, which resulted in a significant decrease in FAK phosphorylation at Y397. Accompanied by the dephosphorylation of FAK, rhMG53 uncoupled FAK-Src interaction and reduced the phosphorylation of Src at Y416. Consequently, the activation of FAK/Src downstream signalling pathways, such as Akt and ERK1/2, was also significantly inhibited by rhMG53. Furthermore, rhMG53 remarkably decreased HUVEC migration and tube formation in vitro and postnatal mouse retinal angiogenesis in vivo. Taken together, these data indicate that rhMG53 inhibits angiogenesis through regulating FAK/Src/Akt/ERK1/2 signalling pathways. This may provide a novel molecular mechanism for the impaired angiogenesis in ischaemic diseases.

The murine DCs transfected with DNA-plasmid encoding CCR9 demonstrate the increased migration to CCL25 and thymic cells in vitro and to the thymus in vivo.

BACKGROUND: B220+CD11c+plasmacytoid DCs(pDCs) are known to participate in the negative selection and central tolerance induction by the capturing of self-antigens in peripheral tissues and further migration to the thymus using the CCL25-CCR9 chemotaxis axis. AIM: Here we investigate the possibility of DCs migration stimulation to the thymus by the transfection with plasmid DNA-constructs encoding CCR9(pmaxCCR9) to develop a system for desired antigen delivery to the thymus for central tolerance induction. METHODS: Dendritic cells(DCs) cultures were generated from UBC-GFP mice bone marrow cells expressing green fluorescent protein using the rmFlt3-L. DCs cultures were transfected with pmaxCCR9 by electroporation. The efficiency of electroporation was confirmed by RT-qPCR and flow cytometry. The migration of electroporated DCs was assessed in vitro and in vivo. RESULTS: Dendritic cells(DCs) cultures obtained from UBC-GFP mice contained both B220+pDCs and SIRPa+cDC2. According to the RT-qPCR assay, the electroporation of obtained DCs cultures with pmaxCCR9 resulted in a 94.4-fold increase of RNA encoding CCR9 compared with non-electroporated cultures. Flow cytometry data showed that DCs cultures electroporated with pmaxCCR9 contained a significantly higher frequency of DCs carrying significantly higher levels of surface CCR9. Migration dynamics of obtained DCs analyzed in vitro showed that pmaxCCR9 electroporated DCs migrated significantly more active to CCL25 and thymic cells than non-electroporated and mock-electroporated DCs. In vivo, 30 days after injection, the relative amount of the DCs electroporated with pmaxCCR9 and pmaxMHC encoding antigenic determinants in the mice thymuses was 2.02-fold higher than the relative amount of the DCs electroporated with control plasmid. CONCLUSION: Thus, the electroporation of murine DCs with pmaxCCR9 stimulated its migration to CCL25 and thymic cells in vitro as well as to the thymus in vivo. The obtained DCs loaded with a desired antigen may be suggested for further evaluation of central tolerance induction ability in in vivo models of autoimmune diseases and transplantation.

Expression of a recombinant FLT3 ligand and its emtansine conjugate as a therapeutic candidate against acute myeloid leukemia cells with FLT3 expression.

BACKGROUND: Most patients with acute myeloid leukemia (AML) remain uncurable and require novel therapeutic methods. Gain-of-function FMS-like tyrosine kinase 3 (FLT3) mutations are present in 30-40% of AML patients and serve as an attractive therapeutic target. In addition, FLT3 is aberrantly expressed on blasts in > 90% of patients with AML, making the FLT3 ligand-based drug conjugate a promising therapeutic strategy for the treatment of patients with AML. Here, E. coli was used as a host to express recombinant human FLT3 ligand (rhFL), which was used as a specific vehicle to deliver cytotoxic drugs to FLT3 + AML cells. METHODS: Recombinant hFL was expressed and purified from induced recombinant BL21 (DE3) E. coli. Purified rhFL and emtansine (DM1) were conjugated by an N-succinimidyl 3-(2-pyridyldithio)propionate (SPDP) linker. We evaluated the potency of the conjugation product FL-DM1 against FLT3-expressing AML cells by examining viability, apoptosis and the cell cycle. The activation of proteins related to the activation of FLT3 signaling and apoptosis pathways was detected by immunoblotting. The selectivity of FL-DM1 was assessed in our unique HCD-57 cell line, which was transformed with the FLT3 internal tandem duplication mutant (FLT3-ITD). RESULTS: Soluble rhFL was successfully expressed in the periplasm of recombinant E. coli. The purified rhFL was bioactive in stimulating FLT3 signaling in AML cells, and the drug conjugate FL-DM1 showed activity in cell signaling and internalization. FL-DM1 was effective in inhibiting the survival of FLT3-expressing THP-1 and MV-4-11 AML cells, with half maximal inhibitory concentration (IC50) of 12.9 nM and 1.1 nM. Additionally, FL-DM1 induced caspase-3-dependent apoptosis and arrested the cell cycle at the G2/M phase. Moreover, FL-DM1 selectively targeted HCD-57 cells transformed by FLT3-ITD but not parental HCD-57 cells without FLT3 expression. FL-DM1 can also induce obvious apoptosis in primary FLT3-positive AML cells ex vivo. CONCLUSIONS: Our data demonstrated that soluble rhFL can be produced in a bioactive form in the periplasm of recombinant E. coli. FL can be used as a specific vehicle to deliver DM1 into FLT3-expressing AML cells. FL-DM1 exhibited cytotoxicity in FLT3-expressing AML cell lines and primary AML cells. FL-DM1 may have potential clinical applications in treating patients with FLT3-positive AML.

SERINC3 and SERINC5 restrict HIV-1 infectivity and are counteracted by Nef.

HIV-1 Nef and the unrelated mouse leukaemia virus glycosylated Gag (glycoGag) strongly enhance the infectivity of HIV-1 virions produced in certain cell types in a clathrin-dependent manner. Here we show that Nef and glycoGag prevent the incorporation of the multipass transmembrane proteins serine incorporator 3 (SERINC3) and SERINC5 into HIV-1 virions to an extent that correlates with infectivity enhancement. Silencing of both SERINC3 and SERINC5 precisely phenocopied the effects of Nef and glycoGag on HIV-1 infectivity. The infectivity of nef-deficient virions increased more than 100-fold when produced in double-knockout human CD4(+) T cells that lack both SERINC3 and SERINC5, and re-expression experiments confirmed that the absence of SERINC3 and SERINC5 accounted for the infectivity enhancement. Furthermore, SERINC3 and SERINC5 together restricted HIV-1 replication, and this restriction was evaded by Nef. SERINC3 and SERINC5 are highly expressed in primary human HIV-1 target cells, and inhibiting their downregulation by Nef is a potential strategy to combat HIV/AIDS.

Variation in tumor pH affects pH-triggered delivery of peptide-modified magnetic nanoparticles.

Acidification of the extracellular matrix, an intrinsic characteristic of many solid tumors, is widely exploited for physiologically triggered delivery of contrast agents, drugs, and nanoparticles to tumor. However, pH of tumor microenvironment shows intra- and inter-tumor variation. Herein, we investigate the impact of this variation on pH-triggered delivery of magnetic nanoparticles (MNPs) modified with pH-(low)-insertion peptide (pHLIP). Fluorescent flow cytometry, laser confocal scanning microscopy and transmission electron microscopy data proved that pHLIP-conjugated MNPs interacted with 4T1 cells in two-dimensional culture and in spheroids more effectively at pH 6.4 than at pH 7.2, and entered the cell via clathrin-independent endocytosis. The accumulation efficiency of pHLIP-conjugated MNPs in 4T1 tumors after their intravenous injection, monitored in vivo by magnetic resonance imaging, showed variation. Analysis of the tumor pH profiles recorded with implementation of original nanoprobe pH sensor, revealed obvious correlation between pH measured in the tumor with the amount of accumulated MNPs.

Antiviral Potential of Algal Metabolites-A Comprehensive Review.

Historically, algae have stimulated significant economic interest particularly as a source of fertilizers, feeds, foods and pharmaceutical precursors. However, there is increasing interest in exploiting algal diversity for their antiviral potential. Here, we present an overview of 50-years of scientific and technological developments in the field of algae antivirals. After bibliometric analysis of 999 scientific references, a survey of 16 clinical trials and analysis of 84 patents, it was possible to identify the dominant algae, molecules and viruses that have been shaping and driving this promising field of research. A description of the most promising discoveries is presented according to molecule class. We observed a diverse range of algae and respective molecules displaying significant antiviral effects against an equally diverse range of viruses. Some natural algae molecules, like carrageenan, cyanovirin or griffithsin, are now considered prime reference molecules for their outstanding antiviral capacity. Crucially, while many algae antiviral applications have already reached successful commercialization, the large spectrum of algae antiviral capacities already identified suggests a strong potential for future expansion of this field.

VISTA-Ig ameliorates OXA-induced allergic dermatitis symptoms in mice.

BACKGROUND: Allergic dermatitis (AD) is a chronic inflammatory skin disease that a variety of immune cells are involved in the progression of AD. Among them, T cells are one of major players of AD pathogenesis. The V-domain Ig suppressor of T cell activation (VISTA) has been reported that it has a potential immunomodulatory for T cell response. OBJECTIVE: This study aimed to investigate immunomodulatory of recombinant VISTA-Ig fusion protein in AD mice model. METHODS: The model of AD was built with oxazolone (OXA) in BALB/c mice, then VISTA-Ig was used to treat AD by intraperitoneal (IP) injection. The ear thickness was measured by a digital thickness gauge. The ears tissues were collected and subjected to hematoxylin-eosin (H&E) and toluidine blue (TB) staining. The secretion levels of IL-4 and IgE in the serum were measured by enzyme linked immunosorbent assay (ELISA). The mRNA expression levels of inflammatory cytokines (IL-1ß, IL-6, IL-12, and INF-γ) in ear tissues were measured using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). RESULTS: Treatment with VISTA-Ig successfully alleviated the symptoms of AD, such as erythema, horny substance, and swelling. The infiltration of inflammatory cells was significantly reduced following VISTA-Ig therapy. The secretion levels of IL-4 and IgE in the serum were significantly attenuated following treatment with VISTA-Ig. Additionally, VISTA-Ig observably down-regulated inflammatory cytokines expression in ear tissues. CONCLUSIONS & CLINICAL RELEVANCE: Taken together, our results showed that VISTA-Ig possessed the potential to be a novel immunomodulatory candidate drug against AD.