bims-nimamd 2021-11-21 papers

bims-nimamd

Biomed News

on Neuroimmunity and neuroinflammation in ageing and metabolic disease

Issue of 2021–11–21
sixteen papers selected by
Fawaz Alzaïd, Sorbonne Université

Insulin-stimulated adipocytes secrete lactate to promote endothelial fatty acid uptake and transport.
Randomized controlled-feeding study of dietary emulsifier carboxymethylcellulose reveals detrimental impacts on the gut microbiota and metabolome.
Anti-inflammatory and anti-fibrotic effects of modafinil in nonalcoholic liver disease.
Emerging Roles of T Cells in the Pathogenesis of Nonalcoholic Steatohepatitis and Hepatocellular Carcinoma.
Circulating innate lymphoid cell subtypes and altered cytokine profiles following an atherogenic high-fat diet.
TRIB1 regulates LDL metabolism through CEBPα-mediated effects on the LDL receptor in hepatocytes.
Vitamin D supplementation induces CatG-mediated CD4+ T cell inactivation and restores pancreatic beta-cell function in mice with type 1 diabetes.
Infection and Immunometabolism in the Central Nervous System: A Possible Mechanistic Link Between Metabolic Imbalance and Dementia.
The role of the sphingosine axis in immune regulation: A dichotomy in the anti-inflammatory effects between sphingosine kinase 1 and sphingosine kinase 2-dependent pathways.
Transcriptomic taxonomy and neurogenic trajectories of adult human, macaque, and pig hippocampal and entorhinal cells.
Expression and significance of T lymphocyte subsets, RANTES and inflammatory factors levels in serum of patients with abdominal aortic aneurysm.
Liver X receptors regulate natural killer T cell population and antitumor activity in the liver of mice.
Study on the preparation and function of regulatory T cells from human peripheral blood.
Intercellular nanotubes mediate mitochondrial trafficking between cancer and immune cells.
Evidence supporting a role for circulating macrophages in the regression of vascular remodeling following sub-chronic exposure to hemoglobin plus hypoxia.
Astrocytes Downregulate Inflammation in Lipopolysaccharide-Induced Acute Respiratory Distress Syndrome: Applicability to COVID-19.

J Cell Sci. 2021 Nov 15. pii: jcs.258964. [Epub ahead of print]

Insulin-stimulated adipocytes secrete lactate to promote endothelial fatty acid uptake and transport.

Ayon Ibrahim, Michael D Neinast, Kristina Li, Michael Noji, Boa Kim, Marc R Bornstein, Raffiu Mohammed, Kathryn E Wellen, Zolt Arany.

  Insulin stimulates adipose tissue to extract fatty acids from circulation and sequester them inside adipose cells. How fatty acids are transported across the capillary endothelial barrier, or how this process is regulated, remains unclear. We modeled the relationship of adipocytes and endothelial cells in vitro to test the role of insulin in fatty acid transport. Treatment of endothelial cells with insulin did not affect endothelial fatty acid uptake, but endothelial cells took up more fatty acids when exposed to media conditioned by adipocytes treated with insulin. Manipulations of this conditioned media indicated that the secreted factor is a small, hydrophilic, non-proteinaceous metabolite. Factor activity was correlated with lactate concentration, and inhibition of lactate production in adipocytes abolished the activity. Finally, lactate alone was sufficient to increase endothelial uptake of both free fatty acids and lipids liberated from chylomicrons, and to promote trans-endothelial transport, at physiologically relevant concentrations. Together, these data suggest that insulin drives adipocytes to secrete lactate, which then acts in a paracrine fashion to promote fatty acid uptake and transport across the neighboring endothelial barrier.

Keywords:  Adipose tissue; Endothelium; Fatty acids; Lactate; Paracrine

DOI:  https://doi.org/10.1242/jcs.258964
Gastroenterology. 2021 Nov 10. pii: S0016-5085(21)03728-8. [Epub ahead of print]

Randomized controlled-feeding study of dietary emulsifier carboxymethylcellulose reveals detrimental impacts on the gut microbiota and metabolome.

Benoit Chassaing, Charlene Compher, Brittaney Bonhomme, Qing Liu, Yuan Tian, William Walters, Lisa Nessel, Clara Delaroque, Fuhua Hao, Victoria Gershuni, Lillian Chau, Josephine Ni, Meenakshi Bewtra, Lindsey Albenberg, Alexis Bretin, Liam McKeever, Ruth E Ley, Andrew D Patterson, Gary D Wu, Andrew T Gewirtz, James D Lewis.

   BACKGROUND & AIMS: Epidemiologic and murine studies suggest that dietary emulsifiers promote development of diseases associated with microbiota dysbiosis. While the detrimental impact of these compounds on the intestinal microbiota and intestinal health have been demonstrated in animal and in vitro models, impact of these food additives in healthy humans remains poorly characterized.
METHODS: To examine this notion in humans, we performed a double-blind controlled-feeding study of the ubiquitous synthetic emulsifier carboxymethylcellulose (CMC) in which healthy adults consumed only emulsifier-free diets (n=9) or an identical diet enriched with 15 grams per day of CMC (n=7) for 11 days.
RESULTS: Relative to control subjects, CMC consumption modestly increased postprandial abdominal discomfort and perturbed gut microbiota composition in a way that reduced its diversity. Moreover, CMC-fed subjects exhibited changes in the fecal metabolome, particularly reductions in short-chain fatty acids and free amino acids. Furthermore, we identified 2 subjects consuming CMC who exhibited increased microbiota encroachment into the normally sterile inner mucus layer, a central feature of gut inflammation, as well as stark alterations in microbiota composition.
CONCLUSIONS: These results support the notion that the broad use of CMC in processed foods may be contributing to increased prevalence of an array of chronic inflammatory diseases by altering the gut microbiome and metabolome.

Keywords:  Emulsifier; Metabolism; Metabolome; Microbiota

DOI:  https://doi.org/10.1053/j.gastro.2021.11.006
Biomed Pharmacother. 2021 Dec;pii: S0753-3322(21)01156-2. [Epub ahead of print]144 112372

Anti-inflammatory and anti-fibrotic effects of modafinil in nonalcoholic liver disease.

Shinkyu Choi, Ji Aee Kim, Haiyan Li, Seong-Eun Jo, Huisu Lee, Tae Hun Kim, Minje Kim, Seong-Jin Kim, Suk Hyo Suh.

  Small- and intermediate-conductance Ca2+-activated K+ channels, KCa2.3 and KCa3.1, are involved in cellular signaling processes associated with inflammation and fibrosis. KCa2.3 and KCa3.1 are upregulated by proinflammatory cytokines and profibrotic growth factors. Cyclic AMP, which downregulates KCa2.3 and KCa3.1, is elevated by modafinil in cells; accordingly, we investigated whether modafinil exerts anti-inflammatory and anti-fibrotic responses via KCa2.3- and KCa3.1-mediated pathways in high-fat diet (HFD)- or thioacetamide-induced liver disease models in mice. Modafinil was administered orally in the form of a racemate, (R)-isomer, or (S)-isomer. We also determined whether the treatment targeted the profibrotic activity of hepatic stellate cells using immortalized human hepatic stellate cells (LX-2 cells). Modafinil improved HFD- or thioacetamide-induced changes compared to the control, leading to a reduced inflammatory response, collagen deposition, and α-smooth muscle actin expression both in vivo and in vitro. However, modafinil did not relieve HFD-induced steatosis. There were no significant differences in the effects of the (R)- and (S)-isomers of modafinil. KCa2.3 and KCa3.1 were upregulated and catalase was downregulated in liver tissues from thioacetamide- or HFD-induced liver disease models or in TGF-β-treated LX-2 cells. TGF-β-induced upregulation of KCa2.3, KCa3.1, collagen, and α-smooth muscle actin and downregulation of catalase were reversed by modafinil, polyethylene glycol catalase, N-acetylcysteine, siRNA against KCa2.3 or KCa3.1, and Epac inhibitors. Our investigation revealed that modafinil attenuated inflammatory and fibrotic progression via KCa2.3- and KCa3.1-mediated pathways in nonalcoholic hepatitis, suggesting that inhibiting KCa2.3- and KCa3.1-mediated signaling may serve as a novel therapeutic approach for inflammatory and fibrotic liver diseases.

Keywords:  Fibrosis; Inflammation; K(Ca)2.3 and K(Ca)3.1; Liver disease; Modafinil

DOI:  https://doi.org/10.1016/j.biopha.2021.112372
Front Endocrinol (Lausanne). 2021 ;12 760860

Emerging Roles of T Cells in the Pathogenesis of Nonalcoholic Steatohepatitis and Hepatocellular Carcinoma.

Petra Hirsova, Adebowale O Bamidele, Haiguang Wang, Davide Povero, Xavier S Revelo.

  Nonalcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease worldwide. A significant proportion of patients with NAFLD develop a progressive inflammatory condition termed nonalcoholic steatohepatitis (NASH), which may eventually advance to cirrhosis and hepatocellular carcinoma (HCC). NASH is characterized by steatosis, hepatocyte ballooning, and lobular inflammation. Heightened immune cell infiltration is a hallmark of NASH, yet the mechanisms whereby hepatic inflammation occurs in NASH and how it contributes to disease initiation and progression remain incompletely understood. Emerging evidence indicates that intrahepatic T cell immune mechanisms play an integral role in the pathogenesis of NASH and its transition to HCC. In this review, we summarize the current knowledge regarding the T cell-mediated mechanisms of inflammation in NASH. We highlight recent preclinical and human studies implicating various subsets of conventional and innate-like T cells in the onset and progression of NASH and HCC. Finally, we discuss the potential therapeutic strategies targeting T cell-mediated responses for the treatment of NASH.

Keywords:  CD4/CD8 lymphocytes; HCC; Inflammation; NASH; T cells

DOI:  https://doi.org/10.3389/fendo.2021.760860
Innate Immun. 2021 Nov 17. 17534259211053634

Circulating innate lymphoid cell subtypes and altered cytokine profiles following an atherogenic high-fat diet.

Vuyolwethu Mxinwa, Phiwayinkosi V Dludla, Tawanda M Nyambuya, Bongani B Nkambule.

  Impaired Glc tolerance and hyperinsulinemia are a hallmark of type 2 diabetes (T2D) and are associated with an altered innate and adaptive immune response. In this study, we used a high-fat diet (HFD)-induced model of pre-diabetes to explore the pathological implications of altered innate lymphoid cell (ILC) profiles in a state of impaired Glc tolerance. Sixteen male C57BL/6 mice were randomized to receive two experimental diets (n = 8 per group), low-fat (LFD), and HFD for 8-13 wk. We evaluated the levels of circulating innate lymphoid cells and their respective cytokines following HFD-feeding. The HFD group had impaired Glc tolerance, elevated insulin levels, and increased total cholesterol levels. Notably, the levels of circulating ILC1s were elevated following 13 wk of HFD-feeding. Moreover, the levels of TNF-α were decreased, but there were no changes in IFN-γ levels. Lastly, the levels of circulating ILC2s and ILC3s were comparable between the HFD and LFD group. The findings demonstrated that short-term HFD-feeding increases postprandial blood Glc, total cholesterol and insulin levels. However, the metabolic changes did not alter ILC2 and ILC3 levels and their respective cytokine profiles.

Keywords:  Glc metabolism; inflammation; innate lymphoid cells; insulin resistance; type 2 diabetes mellitus

DOI:  https://doi.org/10.1177/17534259211053634
J Clin Invest. 2021 Nov 15. pii: e146775. [Epub ahead of print]131(22):

TRIB1 regulates LDL metabolism through CEBPα-mediated effects on the LDL receptor in hepatocytes.

Katherine Quiroz-Figueroa, Cecilia Vitali, Donna M Conlon, John S Millar, John W Tobias, Robert C Bauer, Nicholas J Hand, Daniel J Rader.

  Genetic variants near the TRIB1 gene are highly significantly associated with plasma lipid traits and coronary artery disease. While TRIB1 is likely causal of these associations, the molecular mechanisms are not well understood. Here we sought to investigate how TRIB1 influences low density lipoprotein cholesterol (LDL-C) levels in mice. Hepatocyte-specific deletion of Trib1 (Trib1Δhep) in mice increased plasma cholesterol and apoB and slowed the catabolism of LDL-apoB due to decreased levels of LDL receptor (LDLR) mRNA and protein. Simultaneous deletion of the transcription factor CCAAT/enhancer-binding protein alpha (CEBPα) with TRIB1 eliminated the effects of TRIB1 on hepatic LDLR regulation and LDL catabolism. Using RNA-seq, we found that activating transcription factor 3 (Atf3) was highly upregulated in the livers of Trib1Δhep but not Trib1Δhep CebpaΔhep mice. ATF3 has been shown to directly bind to the CEBPα protein, and to repress the expression of LDLR by binding its promoter. Blunting the increase of ATF3 in Trib1Δhep mice reduced the levels of plasma cholesterol and partially attenuated the effects on LDLR. Based on these data, we conclude that deletion of Trib1 leads to a posttranslational increase in CEBPα, which increases ATF3 levels, thereby contributing to the downregulation of LDLR and increased plasma LDL-C.

Keywords:  Cardiovascular disease; Cholesterol; Genetics; Lipoproteins; Metabolism

DOI:  https://doi.org/10.1172/JCI146775
Am J Physiol Endocrinol Metab. 2021 Nov 15.

Vitamin D supplementation induces CatG-mediated CD4+ T cell inactivation and restores pancreatic beta-cell function in mice with type 1 diabetes.

Xiaoyang Lai, Xuyang Liu, Xia Cai, Fang Zou.

  Type 1 diabetes (T1D) is a chronic autoimmune disease accompanied by the immune-mediated destruction of pancreatic β-cells. In this study, we aimed to explore the regulatory effects of Vitamin D (VD) supplementation on pancreatic β-cell function by altering the expression of bioinformatically identified cathepsin G (CatG) in T1D model mice. A T1D mouse model was established in non-obese diabetic (NOD) mice, and their islets were isolated and purified. Pancreatic mononuclear cells (MNCs) were collected, from which CD4+ T cells were isolated. The levels of interleukin (IL)-2, IL-10, tumor necrosis factor-α (TNF-α) and interferon-gamma (IFN-γ) in the supernatant of mouse pancreatic tissue homogenate were assessed using ELISA. Immunohistochemistry and TUNEL staining were conducted to evaluate the effects of VD supplementation on pancreatic tissues of T1D mice. The pancreatic beta-cell line MIN6 was used for in vitro substantiation of findings in vivo. VD supplementation reduced glucose levels and improved glucose tolerance in T1D mice. Further, VD supplementation improved pancreatic β-cell function and suppressed immunological and inflammatory reactions in the T1D mice. We documented overexpression of CatG in diabetes tissue samples, and then showed that VD supplementation normalized the islet immune microenvironment through down-regulating CatG expression in T1D mice. Experiments in vitro subsequently demonstrated that VD supplementation impeded CD4+ T activation by down-regulating CatG expression, and thereby enhanced pancreatic β-cell function. Results of the present study elucidated that VD supplementation can down-regulate the expression of CatG and inhibit CD4+ T cell activation, thereby improving β-cell function in T1D.

Keywords:  CD4+ T cell; Cathepsin G; Pancreatic β-cell; Type 1 diabetes; Vitamin D

DOI:  https://doi.org/10.1152/ajpendo.00066.2021
Front Cell Neurosci. 2021 ;15 765217

Infection and Immunometabolism in the Central Nervous System: A Possible Mechanistic Link Between Metabolic Imbalance and Dementia.

Noriko Shinjyo, Kiyoshi Kita.

  Metabolic syndromes are frequently associated with dementia, suggesting that the dysregulation of energy metabolism can increase the risk of neurodegeneration and cognitive impairment. In addition, growing evidence suggests the link between infections and brain disorders, including Alzheimer's disease. The immune system and energy metabolism are in an intricate relationship. Infection triggers immune responses, which are accompanied by imbalance in cellular and organismal energy metabolism, while metabolic disorders can lead to immune dysregulation and higher infection susceptibility. In the brain, the activities of brain-resident immune cells, including microglia, are associated with their metabolic signatures, which may be affected by central nervous system (CNS) infection. Conversely, metabolic dysregulation can compromise innate immunity in the brain, leading to enhanced CNS infection susceptibility. Thus, infection and metabolic imbalance can be intertwined to each other in the etiology of brain disorders, including dementia. Insulin and leptin play pivotal roles in the regulation of immunometabolism in the CNS and periphery, and dysfunction of these signaling pathways are associated with cognitive impairment. Meanwhile, infectious complications are often comorbid with diabetes and obesity, which are characterized by insulin resistance and leptin signaling deficiency. Examples include human immunodeficiency virus (HIV) infection and periodontal disease caused by an oral pathogen Porphyromonas gingivalis. This review explores potential interactions between infectious agents and insulin and leptin signaling pathways, and discuss possible mechanisms underlying the relationship between infection, metabolic dysregulation, and brain disorders, particularly focusing on the roles of insulin and leptin.

Keywords:  dementia; glia; immunometabolism; infection; insulin; leptin; neuroinflammation

DOI:  https://doi.org/10.3389/fncel.2021.765217
Int J Immunopathol Pharmacol. 2021 Jan-Dec;35:35 20587384211053274

The role of the sphingosine axis in immune regulation: A dichotomy in the anti-inflammatory effects between sphingosine kinase 1 and sphingosine kinase 2-dependent pathways.

Yuval Ishay, Dvorah Rotnemer-Golinkin, Yaron Ilan.

  Background: Sphingosine kinase has been identified as playing a central role in the immune cascade, being a common mediator in the cellular response to a variety of signals. The different effects of sphingosine kinase 1 and 2 (SphK1 and SphK2, respectively) activity have not been completely characterized. Aim: To determine the different roles played by SphK1 and SphK2 in the regulation of immune-mediated disorders. Methods: Nine groups of mice were studied. Concanavalin A (ConA) injection was used to induce immune-mediated hepatitis. Mice were treated with SphK1 inhibitor (termed SphK-I) and SphK2 inhibitor (termed ABC294640), prior to ConA injection, and effects of treatment on liver enzymes, subsets of T lymphocytes, and serum levels of cytokines were observed. Results: While liver enzyme elevation was ameliorated by administration of SphK1 inhibitor, SphK2 inhibitor-treated mice did not show this tendency. A marked decrease in expression of CD25+ T-cells and Foxp+ T-cells was observed in mice treated with a high dose of SphK1 inhibitor. Alleviation of liver damage was associated with a statistically significant reduction of serum IFNγ levels in mice treated with SphK1 inhibitor and not in those treated with SphK2 inhibitor. Conclusions: Early administration of SphK1 inhibitor in a murine model of immune-mediated hepatitis alleviated liver damage and inflammation with a statistically significant reduction in IFN-γ levels. The data support a dichotomy in the anti-inflammatory effects of SphK1 and SphK2, and suggests that isoenzyme-directed therapies can improve the effect of targeting these pathways.

Keywords:  immune-mediated hepatitis; sphingolipids; sphingosine kinase 1; sphingosine kinase 2

DOI:  https://doi.org/10.1177/20587384211053274
Neuron. 2021 Nov 18. pii: S0896-6273(21)00866-7. [Epub ahead of print]

Transcriptomic taxonomy and neurogenic trajectories of adult human, macaque, and pig hippocampal and entorhinal cells.

Daniel Franjic, Mario Skarica, Shaojie Ma, Jon I Arellano, Andrew T N Tebbenkamp, Jinmyung Choi, Chuan Xu, Qian Li, Yury M Morozov, David Andrijevic, Zvonimir Vrselja, Ana Spajic, Gabriel Santpere, Mingfeng Li, Shupei Zhang, Yang Liu, Joshua Spurrier, Le Zhang, Ivan Gudelj, Lucija Rapan, Hideyuki Takahashi, Anita Huttner, Rong Fan, Stephen M Strittmatter, Andre M M Sousa, Pasko Rakic, Nenad Sestan.

  The hippocampal-entorhinal system supports cognitive functions, has lifelong neurogenic capabilities in many species, and is selectively vulnerable to Alzheimer's disease. To investigate neurogenic potential and cellular diversity, we profiled single-nucleus transcriptomes in five hippocampal-entorhinal subregions in humans, macaques, and pigs. Integrated cross-species analysis revealed robust transcriptomic and histologic signatures of neurogenesis in the adult mouse, pig, and macaque but not humans. Doublecortin (DCX), a widely accepted marker of newly generated granule cells, was detected in diverse human neurons, but it did not define immature neuron populations. To explore species differences in cellular diversity and implications for disease, we characterized subregion-specific, transcriptomically defined cell types and transitional changes from the three-layered archicortex to the six-layered neocortex. Notably, METTL7B defined subregion-specific excitatory neurons and astrocytes in primates, associated with endoplasmic reticulum and lipid droplet proteins, including Alzheimer's disease-related proteins. This resource reveals cell-type- and species-specific properties shaping hippocampal-entorhinal neurogenesis and function.

Keywords:  Alzheimer’s disease; METTL7B; adult neurogenesis; doublecortin; entorhinal cortex; evolution; hippocampus; immature neurons; neuroblast; single-cell RNA-seq

DOI:  https://doi.org/10.1016/j.neuron.2021.10.036
Am J Transl Res. 2021 ;13(10): 11987-11992

Expression and significance of T lymphocyte subsets, RANTES and inflammatory factors levels in serum of patients with abdominal aortic aneurysm.

Xu Xie, Ze Song, Lei Wang, Ming Qi.

OBJECTIVE: To investigate the expression levels and significance of T lymphocyte subsets, RANTES (regulated on activation, normal T cell expressed and secreted), and inflammatory factors in serum of patients with abdominal aortic aneurysm (AAA).
METHODS: 32 patients each with large (large AAA) and small (small AAA) groups were selected, and 32 normal subjects were selected as control group. Serum C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), RANTES and CD4+ T cells, CD8+ T cells and CD4+/CD8+ expressions in peripheral blood were compared among the three groups.
RESULTS: Compared with control group, CRP, TNF-α, IL-6, RANTES and CD8+ T cells levels were higher in large and small AAA groups, while CD4+ T cells and CD4+/CD8+ levels were lower (P<0.05). Compared with small AAA group, CRP, TNF-α, IL-6, RANTES and CD8+ T cells levels in large AAA group were higher, while CD4+ T cells and CD4+/CD8+ levels were lower (P<0.05). The abdominal aorta diameter was positively correlated with CRP, TNF-α, IL-6, RANTES and CD8+ T cells levels, while negatively correlated with CD4+ T cells and CD4+/CD8+ levels (P<0.001). Receiver operating characteristic curve results showed that the areas under the curve of CRP, TNF-α, IL-6 and RANTES in the diagnosis of AAA were all more than 0.800 (P<0.001).
CONCLUSION: The serum of patients with AAA was in a state of inflammatory activation, and the expression of T lymphocytes was abnormal. The levels of T lymphocyte subsets, RANTES and inflammatory factors were closely related to abdominal aorta diameter. CRP, TNF-α, IL-6 and RANTES levels could be used as auxiliary indicators for the diagnosis of AAA.

Keywords: Abdominal aortic aneurysm; RANTES; T lymphocyte subsets; inflammatory factors
Sci Rep. 2021 Nov 19. 11(1): 22595

Liver X receptors regulate natural killer T cell population and antitumor activity in the liver of mice.

Kaori Endo-Umeda, Hiroyuki Nakashima, Shigeyuki Uno, Shota Toyoshima, Naoki Umeda, Shihoko Komine-Aizawa, Shuhji Seki, Makoto Makishima.

The nuclear receptors liver X receptor α (LXRα) and LXRβ are lipid sensors that regulate lipid metabolism and immunity. Natural killer T (NKT) cells, a T cell subset expressing surface markers of both natural killer cells and T lymphocytes and involved in antitumor immunity, are another abundant immune cell type in the liver. The potential function of the metabolic regulators LXRα/β in hepatic NKT cells remains unknown. In this study, we examined the role of LXRα and LXRβ in NKT cells using mice deficient for LXRα and/or LXRβ, and found that hepatic invariant NKT (iNKT) cells are drastically decreased in LXRα/β-KO mice. Cytokine production stimulated by the iNKT cell activator α-galactosylceramide was impaired in LXRα/β-KO hepatic mononuclear cells and in LXRα/β-KO mice. iNKT cell-mediated antitumor effect was also disturbed in LXRα/β-KO mice. LXRα/β-KO mice transplanted with wild-type bone marrow showed decreased iNKT cells in the liver and spleen. The thymus of LXRα/β-KO mice showed a decreased population of iNKT cells. In conclusion, LXRα and LXRβ are essential for NKT cell-mediated immunity, such as cytokine production and hepatic antitumor activity, and are involved in NKT cell development in immune tissues, such as the thymus.

DOI: https://doi.org/10.1038/s41598-021-02062-z
Ann Transl Med. 2021 Oct;9(20): 1521

Study on the preparation and function of regulatory T cells from human peripheral blood.

Fengqiong Zuo, Yongjun Chen, Yuzuo Chen, Fang Gao, Yonglin Su, Zaibo Liao, Baoning Wang.

   Background: Regulatory T cells (Tregs) are an important cell subgroup of CD4+ T cells. Treg cells are critically involved in inducing immune tolerance, maintaining immune environment homeostasis, and preventing the occurrence of autoimmune diseases. Under normal conditions, the number of Tregs in the body is very small. This research was designed to establish an effective method to expand human peripheral blood Tregs in vitro and to analyze phenotype, purity, and function of Treg cells post-expansion.
Methods: Peripheral blood was obtained from healthy donors. CD4+CD25+CD127dim/- Treg cells were isolated from peripheral blood mononuclear cells (PBMCs) by magnetic-activated cell sorting (MACS), and an optimized culture system was used for amplification. The in vitro amplification ability of Treg cells was evaluated to determine the expression and purity of Treg cell-specific surface markers in different culture cycles. The suppressive function of Treg was determined by in vitro lymphocyte proliferation assay.
Results: Treg cells could be successfully isolated by magnetic activated cell sorting (MACS). After 21 days of in vitro culture, the mean expansion fold was 2,009±452.2 in ≤60 years, and there was a significant difference between the younger group and the older than 60 years group (1,238±330.0). Flow cytometry analysis revealed that the percentages of CD4+CD25+ cells and FOXP3+ cells were (93.25±3.05)% and (94.19±4.21)% on day 14, and (92.86±4.36)% and (91.55±5.62)% on day 21, respectively. In addition, the proportions of CD8+ T, CD19+ B, CD3-CD56+ natural killer cell (NK), and CD3+ CD56+ natural killer T cell (NKT) were extremely low. Lymphocyte proliferation assay demonstrated that Tregs could inhibit the proliferation of CD8+ T cells more effectively than that of CD4+ T cells. Furthermore, the suppressive capacity of Tregs was correlated with Treg-to-PBMCs ratios.
Conclusions: We successfully established a technical protocol for manufacturing a large quantity of Tregs with high efficiency in vitro. The expanded Tregs have a steady FOXP3 expression and exhibited a potent immune suppression, which might have great significance in adoptive Treg therapy for treating graft-versus-host disease and autoimmune diseases.

Keywords:  Regulatory T cells (Tregs); immune suppression; in vitro expansion

DOI:  https://doi.org/10.21037/atm-21-3812
Nat Nanotechnol. 2021 Nov 18.

Intercellular nanotubes mediate mitochondrial trafficking between cancer and immune cells.

Tanmoy Saha, Chinmayee Dash, Ruparoshni Jayabalan, Sachin Khiste, Arpita Kulkarni, Kiran Kurmi, Jayanta Mondal, Pradip K Majumder, Aditya Bardia, Hae Lin Jang, Shiladitya Sengupta.

Cancer progresses by evading the immune system. Elucidating diverse immune evasion strategies is a critical step in the search for next-generation immunotherapies for cancer. Here we report that cancer cells can hijack the mitochondria from immune cells via physical nanotubes. Mitochondria are essential for metabolism and activation of immune cells. By using field-emission scanning electron microscopy, fluorophore-tagged mitochondrial transfer tracing and metabolic quantification, we demonstrate that the nanotube-mediated transfer of mitochondria from immune cells to cancer cells metabolically empowers the cancer cells and depletes the immune cells. Inhibiting the nanotube assembly machinery significantly reduced mitochondrial transfer and prevented the depletion of immune cells. Combining a farnesyltransferase and geranylgeranyltransferase 1 inhibitor, namely, L-778123, which partially inhibited nanotube formation and mitochondrial transfer, with a programmed cell death protein 1 immune checkpoint inhibitor improved the antitumour outcomes in an aggressive immunocompetent breast cancer model. Nanotube-mediated mitochondrial hijacking can emerge as a novel target for developing next-generation immunotherapy agents for cancer.

DOI: https://doi.org/10.1038/s41565-021-01000-4
Pulm Circ. 2021 Oct-Dec;11(4):11(4): 20458940211056806

Evidence supporting a role for circulating macrophages in the regression of vascular remodeling following sub-chronic exposure to hemoglobin plus hypoxia.

Vijaya Karoor, Delaney Swindle, David I Pak, Derek Strassheim, Mehdi A Fini, Edward Dempsey, Kurt R Stenmark, Kathryn Hassell, Rachelle Nuss, Paul W Buehler, David C Irwin.

  Macrophages are a heterogeneous population with both pro- and anti-inflammatory functions play an essential role in maintaining tissue homeostasis, promoting inflammation under pathological conditions, and tissue repair after injury. In pulmonary hypertension, the M1 phenotype is more pro-inflammatory compared to the M2 phenotype, which is involved in tissue repair. The role of macrophages in the initiation and progression of pulmonary hypertension is well studied. However, their role in the regression of established pulmonary hypertension is not well known. Rats chronically exposed to hemoglobin (Hb) plus hypoxia (HX) share similarities to humans with pulmonary hypertension associated with hemolytic disease, including the presence of a unique macrophage phenotype surrounding distal vessels that are associated with vascular remodeling. These lung macrophages are characterized by high iron content, HO-1, ET-1, and IL-6, and are recruited from the circulation. Depletion of macrophages in this model prevents the development of pulmonary hypertension and vascular remodeling. In this study, we specifically investigate the regression of pulmonary hypertension over a four-week duration after rats were removed from Hb + HX exposure with and without gadolinium chloride administration. Withdrawal of Hb + HX reversed systolic pressures and right ventricular function after Hb + Hx exposure in four weeks. Our data show that depleting circulating monocytes/macrophages during reversal prevents complete recovery of right ventricular systolic pressure and vascular remodeling in this rat model of pulmonary hypertension at four weeks post exposure. The data presented offer a novel insight into the role of macrophages in the processes of pulmonary hypertension regression in a rodent model of Hb + Hx-driven disease.

Keywords:  heart; hemoglobinopathies; lung; pulmonary vascular disease; sickle cell disease

DOI:  https://doi.org/10.1177/20458940211056806
Front Med (Lausanne). 2021 ;8 740071

Astrocytes Downregulate Inflammation in Lipopolysaccharide-Induced Acute Respiratory Distress Syndrome: Applicability to COVID-19.

Michal Izrael, Kfir Molakandov, Ariel Revel, Shalom Guy Slutsky, Tehila Sonnenfeld, Julia Miriam Weiss, Michel Revel.

  Background: An acute respiratory distress syndrome (ARDS) is caused by the increased amounts of pro-inflammatory cytokines and neutrophil-mediated tissue injury. To date, there is no effective treatment for the ARDS available, while the need for one is growing due to the most severe complications of the current coronavirus disease-2019 (COVID-19) pandemic. The human astrocytes (AstroRx) have shown immunomodulatory properties in the central nervous system (CNS). This study aimed to evaluate the capacity of astrocytes to decrease lung inflammation and to be applied as a treatment therapy in ARDS. Methods: First, we assessed the ability of clinical-grade AstroRx to suppress T-cell proliferation in a mixed lymphocyte reaction test. Next, we tested the therapeutical potential of AstroRx cells in a lipopolysaccharide (LPS)-based ARDS mouse model by injecting AstroRx intravenously (i.v). We determined the degree of lung injury by using a severity scoring scale of 0-2, based on the American Thoracic Society. The scoring measured the presence of neutrophils, fibrin deposits, and the thickening of alveolar walls. The state of inflammation was further assessed by quantifying the immune-cell infiltration to the bronchoalveolar lavage fluid (BALF) and by the presence of proinflammatory cytokines and chemokines in the BALF and serum. Results: We detected that AstroRx cells were capable to suppress T-cell proliferation in vitro after exposure to the mitogen concanavalin A (ConA). In vivo, AstroRx cells were able to lower the degree of lung injury in LPS-treated animals compared with the sham injected animals (P = 0.039). In this study, 30% of AstroRx treated mice showed no lung lesions (responder mice), these mice presented a steady number of eosinophils, T cells, and neutrophils comparable with the level of naïve control mice. The inflammatory cytokines and chemokines, such as TNFα, IL1b, IL-6, and CXCL1, were also kept in check in responder AstroRx-treated mice and were not upregulated as in the sham-injected mice (P < 0.05). As a result, the LPS-treated ARDS mice had a higher survival rate when they were treated with AstroRx. Conclusions: Our results demonstrate that the immunosuppressive activity of AstroRx cells support the application of AstroRx cells as a cell therapy treatment for ARDS. The immunoregulatory activity may also be a part of the mechanism of action of AstroRx reported in the amyotrophic lateral sclerosis (ALS) neurodegenerative disease.

Keywords:  ARDS; astrocytes; embryonic stem cells; immune-modulation; inflammation

DOI:  https://doi.org/10.3389/fmed.2021.740071