High temperature affects the phagocytic activity of human peripheral blood mononuclear cells

Adolescent intermittent ethanol (AIE) sensitized fever in male Sprague Dawley rats exposed to poly I:C in adulthood

Fever plays an indispensable role in host defense processes and is used as a rapid index of infection severity. Unfortunately, there are also substantial individual differences in fever reactions with biological sex, immunological history, and other demographic variables contributing to adverse outcomes of infection. The present series of studies were designed to test the hypothesis that a history of adolescent alcohol misuse may be a latent experiential variable that determines fever severity using polyinosinic:polycytidylic acid (poly I:C), a synthetic form of double-stranded RNA that mimics a viral challenge. Adult male and female Sprague Dawley rats were injected with 0 (saline) or 4 mg/kg poly I:C to first establish sex differences in fever sensitivity in Experiment 1 using implanted radiotelemetry devices for remote tracking. In Experiments 2 and 3, adolescent males and females were exposed to either water or ethanol (0 or 4 g/kg intragastrically, 3 days on, 2 days off, ∼P30-P50, 4 cycles/12 exposures total). After a period of abstinence, adult rats (∼P80-96) were then challenged with saline or poly I:C, and fever induction and maintenance were examined across a prolonged time course of 8 h using implanted probes. In Experiments 4 and 5, adult male and female subjects with a prior history of adolescent water or adolescent intermittent ethanol (AIE) were given saline or poly I:C, with tissue collected for protein and gene expression analysis at 5 h post-injection. Initial sex differences in fever sensitivity were minimal in response to the 4 mg/kg dose of poly I:C in ethanol-naïve rats. AIE exposed males injected with poly I:C showed a sensitized fever response as well as enhanced TLR3, IκBα, and IL-1β expression in the nucleus of the solitary tract. Other brain regions related to thermoregulation and peripheral organs such as spleen, liver, and blood showed generalized immune responses to poly I:C, with no differences evident between AIE and water-exposed males. In contrast, AIE did not affect responsiveness to poly I:C in females. Thus, the present findings suggest that adolescent binge drinking may produce sex-specific and long-lasting effects on fever reactivity to viral infection, with preliminary evidence suggesting that these effects may be due to centrally-mediated changes in fever regulation rather than peripheral immunological mechanisms.

Immune-enhancing activity of polysaccharides and flavonoids derived from Phellinus igniarius YASH1

Introduction: Phellinus igniarius (P. igniarius) (Sanghuang) is a widely used traditional Chinese medicine fungus, and its natural products have great potential for clinical application in immune enhancement. This study aimed to explore the immune-enhancing activity and underlying mechanisms of the polysaccharides and flavonoids derived from Phellinus igniarius (P. igniarius) and to provide a theoretical and experimental basis for the development of novel drugs. Methods: Wild P. igniarius YASH1 from the Loess Plateau in Yan'an region was collected, and polysaccharides and total flavonoids were extracted, isolated and identified from mycelium and sporophore. In vitro antioxidant activity was detected through the scavenging activity of hydroxyl radicals and total antioxidant capacity. Cell Counting Kit-8 and trypan blue detection kit were used to detect the effect of extract polysaccharides and flavonoids on the proliferation and phagocytosis ability of immune cells. To assess the effect of the drugs on cytokine secretion by immune cells and immune recovery in immunocompromised mice, the expression of interleukin (IL)-2, IL-6, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α were examined at the cellular and animal levels. The species composition, abundance of gut microbiota and the altered content of short-chain fatty acids in the feces were analyzed to elucidate the possible mechanisms of drugs by 16S ribosomal RNA (rRNA) amplifiers sequencing and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Results: Both polysaccharides and flavonoids derived from mycelium or sporophore had antioxidant activity and may stimulate the expression and secretion of IL-2, IL-6, and IFN-γ in immune cells while inhibiting TNF-α expression and secretion and increasing IL-2, IL-6, and IFN- γ expression levels in mice. Furthermore, polysaccharides and flavonoids from mycelium and sporophore showed different effects on the metabolic response of intestinal short-chain fatty acids (SCFAs) in mice, and the use of these drugs remarkably changed the species composition and abundance of intestinal flora in mice. Discussion: Polysaccharides and flavonoids from P. igniarius YASH1 mycelium and sporophore have in vitro antioxidant activity, and they affect the promotion of cell proliferation, stimulation of IL-2, IL-6, and IFN-γ secretion, and inhibition of TNF-α expression in immune cells. Polysaccharides and flavonoids from P. igniarius YASH1 may enhance immunity in immunocompromised mice and remarkably affect the intestinal flora and content of SCFAs.

Temperature-sensitive migration dynamics in neutrophil-differentiated HL-60 cells

Cell migration plays an essential role in wound healing and inflammatory processes inside the human body. Peripheral blood neutrophils, a type of polymorphonuclear leukocyte (PMN), are the first cells to be activated during inflammation and subsequently migrate toward an injured tissue or infection site. This response is dependent on both biochemical signaling and the extracellular environment, one aspect of which includes increased temperature in the tissues surrounding the inflammation site. In our study, we analyzed temperature-dependent neutrophil migration using differentiated HL-60 cells. The migration speed of differentiated HL-60 cells was found to correlate positively with temperature from 30 to 42 °C, with higher temperatures inducing a concomitant increase in cell detachment. The migration persistence time of differentiated HL-60 cells was higher at lower temperatures (30-33 °C), while the migration persistence length stayed constant throughout the temperature range. Coupled with the increased speed observed at high temperatures, this suggests that neutrophils are primed to migrate more effectively at the elevated temperatures characteristic of inflammation. Temperature gradients exist on both cell and tissue scales. Taking this into consideration, we also investigated the ability of differentiated HL-60 cells to sense and react to the presence of temperature gradients, a process known as thermotaxis. Using a two-dimensional temperature gradient chamber with a range of 27-43 °C, we observed a migration bias parallel to the gradient, resulting in both positive and negative thermotaxis. To better mimic the extracellular matrix (ECM) environment in vivo, a three-dimensional collagen temperature gradient chamber was constructed, allowing observation of biased neutrophil-like differentiated HL-60 migration toward the heat source.

Cellular Uptake Pathways of Nanoparticles: Process of Endocytosis and Factors Affecting Their Fate

BACKGROUND

Efficient and controlled internalization of NPs into the cells depends on their physicochemical properties and dynamics of the plasma membrane. NPs-cell interaction is a complex process that decides the fate of NPs internalization through different endocytosis pathways.

OBJECTIVE

The aim of this review is to highlight the physicochemical properties of synthesized nanoparticles (NPs) and their interaction with the cellular-dynamics and pathways like phagocytosis, pinocytosis, macropinocytosis, clathrin, and caveolae-mediated endocytosis and the involvement of effector proteins domain such as clathrin, AP2, caveolin, Arf6, Cdc42, dynamin and cell surface receptors during the endocytosis process of NPs.

METHOD

An electronic search was performed to explore the focused reviews and research articles on types of endocytosis and physicochemical properties of nanoparticles and their impact on cellular internalizations. The search was limited to peer-reviewed journals in the PubMed database.

RESULTS

This article discusses in detail how different types of NPs and their physicochemical properties such as size, shape, aspect ratio, surface charge, hydrophobicity, elasticity, stiffness, corona formation, surface functionalization changes the pattern of endocytosis in the presence of different pharmacological blockers. Some external forces like a magnetic field, electric field, and ultrasound exploit the cell membrane dynamics to permeabilize them for efficient internalization with respect to fundamental principles of membrane bending and pore formation.

CONCLUSION

This review will be useful to attract and guide the audience to understand the endocytosis mechanism and their pattern with respect to physicochemical properties of NPs to improve their efficacy and targeting to achieve the impactful outcome in drug-delivery and theranostics applications.

Suppression of Metastatic Melanoma Growth in Lung by Modulated Electro-Hyperthermia Monitored by a Minimally Invasive Heat Stress Testing Approach in Mice

Simple Summary

The lung is the most frequent site of distant melanoma metastases. Metastases of melanoma in the lungs offer a very poor prognosis, with a 5-year survival rate of below 10%. Hyperthermic therapies including modulated electro-hyperthermia (mEHT) in clinical settings have been used to improve the efficacy of radiotherapy, chemotherapy, and immunotherapy of tumors. In this study, we focused primarily on the optimization of mEHT for targeted lung treatment of mice lungs burdened with B16F10 melanoma pulmonary metastases, with a particular focus on elucidating the mechanism of action of mEHT on treated melanoma cells while investigating any potential treatment-related side effects on normal lung tissue. mEHT showed evidence of significant anti-tumor effects as demonstrated by the reduced number of pulmonary metastatic nodules, DNA damage response, downregulation of Ki67 expression, higher immune cell infiltration, and upregulation of p21^waf1 expression in mEHT-treated tumors.

Abstract

Modulated electro-hyperthermia (mEHT) is a novel complementary therapy in oncology which is based on the higher conductivity and permittivity of cancerous tissues due to their enhanced glycolytic activity and ionic content compared to healthy normal tissues. We aimed to evaluate the potential of mEHT, inducing local hyperthermia, in the treatment of pulmonary metastatic melanoma. Our primary objective was the optimization of mEHT for targeted lung treatment as well as to identify the mechanism of its potential anti-tumor effect in the B16F10 mouse melanoma pulmonary metastases model while investigating the potential treatment-related side effects of mEHT on normal lung tissue. Repeated treatment of tumor-bearing lungs with mEHT induced significant anti-tumor effects as demonstrated by the lower number of tumor nodules and the downregulation of Ki67 expression in treated tumor cells. mEHT treatment provoked significant DNA double-strand breaks indicated by the increased expression of phosphorylated H2AX protein in treated tumors, although treatment-induced elevation of cleaved/activated caspase-3 expression was insignificant, suggesting the minimal role of apoptosis in this process. The mEHT-related significant increase in p21^waf1 positive tumor cells suggested that p21^waf1-mediated cell cycle arrest plays an important role in the anti-tumor effect of mEHT on melanoma metastases. Significantly increased CD3+, CD8+ T-lymphocytes, and F4/80+CD11b+ macrophage density in the whole lung and tumor of treated animals emphasizes the mobilizing capability of mEHT on immune cells. In conclusion, mEHT can reduce the growth potential of melanoma, thus offering itself as a complementary therapeutic option to chemo- and/or radiotherapy.

Thermoneutral Housing Temperature Improves Survival in a Murine Model of Polymicrobial Peritonitis

Regulatory guidelines mandate housing for laboratory mice at temperatures below their thermoneutral zone, creating chronic cold stress. However, increases in housing temperature could alter immune responses. We hypothesized housing mice at temperatures within their thermoneutral zone would improve sepsis survival and alter immune responses. Male C57BL/6 mice were housed at 22°C or 30°C after cecal ligation and puncture (CLP) for 10 days. Survival of mice housed at 30°C (78%) after CLP was significantly increased compared with mice housed at 22°C (40%). Experimental groups were repeated with mice euthanized at 0, 12, 24, and 48 h post-surgery to examine select immune parameters. Raising housing temperature minimally altered systemic, peritoneal, or splenic cell counts. However, IL-6 levels in plasma and peritoneal lavage fluid were significantly lower at 12 h post-surgery in mice housed at 30°C compared with 22°C. Bacterial colony counts from peritoneal lavage fluid were significantly lower in mice housed at 30°C and in vivo studies suggested this was the result of increased phagocytosis by neutrophils. As previously demonstrated, adoptive transfer of fibrocytes significantly increased sepsis survival compared with saline at 22°C. However, there was no additive effect when adoptive transfer was performed at 30°C. Overall, the results demonstrated that thermoneutral housing improves survival after CLP by increasing local phagocytic activity and technical revisions may be necessary to standardize the severity of the model across different housing temperatures. These findings stress the pronounced impact housing temperature has on the CLP model and the importance of reporting housing temperature.

Investigating gene expression profiles of whole blood and peripheral blood mononuclear cells using multiple collection and processing methods

Gene expression profiling using blood samples is a valuable tool for biomarker discovery in clinical studies. Different whole blood RNA collection and processing methods are highly variable and might confound comparisons of results across studies. The main aim of the current study is to compare how blood storage, extraction methodologies, and the blood components themselves may influence gene expression profiling. Whole blood and peripheral blood mononuclear cell (PBMC) samples were collected in triplicate from five healthy donors. Whole blood was collected in RNAgard® and PAXgene® Blood RNA Tubes, as well as in collection tubes with anticoagulants such as dipotassium ethylenediaminetetraacetic acid (K2EDTA) and Acid Citrate Dextrose Solution A (ACD-A). PBMCs were separated using sodium citrate Cell Preparation Tubes (CPT™), FICOLL™, magnetic separation, and the LeukoLOCK™ methods. After blood collection, the LeukoLOCK™, K2EDTA and ACD-A blood tubes were shipped overnight using cold conditions and samples from the rest of the collection were immediately frozen with or without pre-processing. The RNA was isolated from whole blood and PBMCs using a total of 10 different experimental conditions employing several widely utilized RNA isolation methods. The RNA quality was assessed by RNA Integrity Number (RIN), which showed that all PBMC procedures had the highest RIN values when blood was stabilized in TRIzol® Reagent before RNA extraction. Initial data analysis showed that human blood stored and shipped at 4°C overnight performed equally well when checked for quality using RNA integrity number when compared to frozen stabilized blood. Comparisons within and across donor/method replicates showed signal-to-noise patterns which were not captured by RIN value alone. Pathway analysis using the top 1000 false discovery rate (FDR) corrected differentially expressed genes (DEGs) showed frozen vs. cold shipping conditions greatly impacted gene expression patterns in whole blood. However, the top 1000 FDR corrected DEGs from PBMCs preserved after frozen vs. cold shipping conditions (LeukoLOCK™ preserved in RNAlater®) revealed no significantly affected pathways. Our results provide novel insight into how RNA isolation, various storage, handling, and processing methodologies can influence RNA quality and apparent gene expression using blood samples. Careful consideration is necessary to avoid bias resulting from downstream processing. Better characterization of the effects of collection method idiosyncrasies will facilitate further research in understanding the effect of gene expression variability in human sample types.

The small GTPase RAB-35 facilitates the initiation of phagosome maturation and acts as a robustness factor for apoptotic cell clearance

We recently identified the novel function of the small GTPase RAB-35 in apoptotic cell clearance in Caenorhabditis elegans, a process in which dying cells are engulfed and degraded inside phagosomes. We have found that RAB-35 functions in two separate steps of cell corpse clearance, cell corpse recognition and the initiation of phagosome maturation. During the latter process, RAB-35 facilitates the removal of phosphatidylinositol-4,5-bisphosphate (PI(4,5)P₂) from the membranes of nascent phagosomes and the simultaneous production of phosphatidylinositol-3-P (PI(3)P) on these same membranes, a process that we have coined the PI(4,5)P₂ to PI(3)P shift. RAB-35 also promotes the recruitment of the small GTPase RAB-5 to the phagosomal surface. During these processes, the activity of RAB-35 is controlled by the candidate GTPase-activating protein (GAP) TBC-10 and the candidate guanine nucleotide exchange factor (GEF) FLCN-1. Overall, RAB-35 leads a third pathway during cell corpse clearance that functions in parallel to the two known pathways, one led by the phagocytic receptor CED-1 and the other led by the CED-10/Rac1 GTPase. Here, we further report that RAB-35 acts as a robustness factor that maintains the clearance activity and embryonic viability under conditions of heat stress. Moreover, we obtained additional evidence suggesting that RAB-35 acts upstream of RAB-5 and RAB-7. To establish a precise temporal pattern for its own dissociation from phagosomal surfaces, RAB-35 controls the removal of its own GAP. We propose that RAB-35 defines a largely unexplored initial phase of phagosome maturation.

Stress-Induced, p53-Mediated Tumor Growth Inhibition of Melanoma by Modulated Electrohyperthermia in Mouse Models without Major Immunogenic Effects

Modulated electrohyperthermia (mEHT), an innovative complementary technique of radio-, chemo-, and targeted oncotherapy modalities, can induce tumor apoptosis and contribute to a secondary immune-mediated cancer death. Here, we tested the efficiency of high-fever range (~42 °C) mEHT on B16F10 melanoma both in cell culture and allograft models. In vivo, mEHT treatment resulted in significant tumor size reduction when repeated three times, and induced major stress response as indicated by upregulated cytoplasmic and cell membrane hsp70 levels. Despite the increased PUMA and apoptosis-inducing factor 1, and moderate rise in activated-caspase-3, apoptosis was not significant. However, phospho-H2AX indicated DNA double-strand breaks, which upregulated p53 protein and its downstream cyclin-dependent kinase inhibitors p21^waf1 and p27^kip. Combined in vitro treatment with mEHT and the p53 activator nutlin-3a additively reduced cell viability compared to monotherapies. Though mEHT promoted the release of damage-associated molecular pattern (DAMP) damage signaling molecules hsp70, HMGB1 and ATP to potentiate the tumor immunogenicity of melanoma allografts, it reduced MHC-I and melan-A levels in tumor cells. This might explain why the number of cytotoxic T cells was moderately reduced, while the amount of natural killer (NK) cells was mainly unchanged and only macrophages increased significantly. Our results suggest that mEHT-treatment-related tumor growth control was primarily mediated by cell-stress-induced p53, which upregulated cyclin-dependent kinase inhibitors. The downregulated tumor antigen-presenting machinery may explain the reduced cytotoxic T-cell response despite increased DAMP signaling. Decreased tumor antigen and MHC-I levels suggest that natural killer (NK) cells and macrophages were the major contributors to tumor eradication.