Gut microbiota as a promising therapeutic target for age-related sarcopenia

Sarcopenia is characterized by a progressive loss of skeletal muscle mass and function with aging. Recently, sarcopenia has been shown to be closely related with gut microbiota. Strategies such as probiotics and fecal microbiota transplantation have shown potential to ameliorate the muscle loss. This review will focus on the age-related sarcopenia, in particular on the relationship between gut microbiota and age-related sarcopenia, how gut microbiota is engaged in sarcopenia, and the potential role of gut microbiota in the treatment of age-related sarcopenia.     

Exhausted NK cells and cytokine storms in COVID-19: Whether NK cell therapy could be a therapeutic choice

The global outbreak of coronavirus-2019 (COVID-19) still claims more lives daily around the world due to the lack of a definitive treatment and the rapid tendency of virus to mutate, which even jeopardizes vaccination efficacy. At the forefront battle against SARS-CoV-2, an effective innate response to the infection has a pivotal role in the initial control and treatment of disease. However, SARS-CoV-2 subtly interrupts the equations of immune responses, disrupting the cytolytic antiviral effects of NK cells, while seriously activating infected macrophages and other immune cells to induce an unleashed “cytokine storm”, a dangerous and uncontrollable inflammatory response causing life-threatening symptoms in patients. Notably, the NK cell exhaustion with ineffective cytolytic function against the sources of exaggerated cytokine release, acts as an Achilles’ heel which exacerbates the severity of COVID-19. Given this, approaches that improve NK cell cytotoxicity may benefit treatment protocols. As a suggestion, adoptive transfer of NK or CAR-NK cells with proper cytotolytic potentials and the lowest capacity of cytokine-release (for example CD56^dim NK cells brightly express activating receptors), to severe COVID-19 patients may provide an effective cure especially in cases suffering from cytokine storms. More intriguingly, the ongoing evidence for persistent clonal expansion of NK memory cells characterized by an activating phenotype in response to viral infections, can benefit the future studies on vaccine development and adoptive NK cell therapy in COVID-19. Whether vaccinated volunteers or recovered patients can also be considered as suitable candidates for cell donation could be the subject of future research.     

Neem Leaf Glycoprotein in immunoregulation of cancer

Cancer is a disease having global consequences. Though several new strategies and treatments have been developed so far, they often come with malicious side effects and this paved ways for demand of naturally extracted/driven product as potent anti-cancer agent owing to their reduced toxicity and side effects. One such common Indian household plant Neem (Azadirachta Indica) and its extract have variegated immunomodulatory effects as anti-cancer agent. Neem Leaf Glycoprotein (NLGP) modifies immune cells present in the tumor surroundings as well as in the peripheral system, rather than directly attacking the cancer cells. NLGP acts as a natural immunomodulator showing several functions like sustained tumor growth regulation by stimulating central and effector memory cells as a vaccination adjuvant, normalization of angiogenic activities, controls hypoxia, improves immune evasion techniques as well as suppresses the activity of several immunological cells (Tregs, myeloid-derived suppressor cells, and tumor-associated macrophages) which promote tumor growth and metastasis in the tumor microenvironment (TME). NLGP prioritises type1 immune-microenvironment which consists of T-bet⁺IFN-γ-producing group 1 innate lymphoid cell (ILC) (ILC1 and natural killer cells), CD8⁺ cytotoxic T cells (TC1), and CD4⁺ T helper1 (Th1) cells. In this review we aim to summarize detailed activity of NLGP in cancer immunoregulation.     

Apelin triggers macrophage polarization to M2 type in head and neck cancer

Cancer comes after cardiovascular diseases in terms of mortality rate in the world. Chemotherapy, radiotherapy and surgical interventions are the current cancer treatment. Recently, it has been observed that immunotherapeutic approaches provide a significant improvement when used along with these interventions. The mononuclear system mainly consists of macrophages that play an active role in the pathology of many diseases because of having high plasticity capacities. Previous research suggested that they can be used as an alternative to cancer treatment. Aim was to investigate the effect of apelin on macrophage polarization in the tumor microenvironment.Mouse macrophage cell line RAW264.7 cells and head and were chosen for this study. The apelin expression was knockdown in neck cell carcinoma cell line SCCL MT1 cells using shRNA technique. SCCL MT1 cells having normal or suppressed apelin expression were co-cultured with mouse macrophage RAW264.7 cells. The effect of co-culturing on the expression of inflammatory genes in RAW264.7 cells was investigated.Suppressed apelin expression in SCCL MT1 cells resulted in elevated pro-inflammatory response in co-cultured macrophages. Expression of the IL1β, IL6, and TNFα genes significantly increased, however anti-inflammatory cytokine levels were significantly decreased. However, in the control group, a downregulation was determined in pro-inflammatory genes, while an increase was observed in anti-inflammatory genes. The protein levels of these cytokines in concordance with the RT-PCR analysis.As a result of this study, apelin released from cancer cells was found to affect macrophage polarization. These results indicated that the apelin peptide may cause the intense presence of M2-type macrophages in the tumor niche, and the therapeutic approaches targeting of apelin in cancer cells may have a potential role in macrophage polarization.     

Association between SARS-CoV-2 infection and de novo HLA donor specific antibody production in lung transplant recipients: Single-center study

The COVID-19 pandemic has led to significant morbidity and mortality in lung transplant recipients. Respiratory viral infections may be associated with de-novo HLA donor-specific antibody production and impact lung transplant outcome. Since one of the immunomodulation strategies post-SARS-CoV-2 infection in lung transplant recipients include decreasing or holding anti-metabolites, concerns have been raised for higher incidence of de-novo HLA donor specific antibody production in lung transplant recipients. We performed a retrospective chart review of 24 consecutive lung transplant recipients diagnosed with COVID-19 to investigate this concern. We observed no significant differences in the CPRA or MFI levels of HLA class I and II antibodies pre- COVID-19 compared to 1 and 6 months post-COVID-19 diagnosis in 11/24 (45.8 %) LTR (p = 0.98 and p = 0.63 respectively). HLA class I and II DSA were detected in 5/24 LTR pre-COVID-19 diagnosis and persisted with no significant differences in the median MFI levels at 1 and 6 months post-COVID-19 diagnosis (p = 0.89). De-novo HLA class I and II DSA were detected in 1/24 (4.2 %) LTR at one month post-COVID-19 diagnosis and persisted with no significant differences in the median MFI levels at 1 and 6 months post-COVID-19 diagnosis (p = 0.54). Our results suggest that there was no significant association between SARS-CoV-2 infection and immunomodulation on pre-existing or de novo HLA donor specific antibodies.     

HLA-G and humanized mouse models as a novel therapeutic approach in transplantation

HLA-G is a nonclassical MHC-Class I molecule whose expression, along the feto-maternal barrier contributes towards tolerance of the semiallogeneic fetus during pregnancy. In light of its inhibitory properties, recent research has established HLA-G involvement in mechanisms responsible for directing allogeneic immune responses towards tolerance during allogeneic situations such as organ transplantation. Here, we critically review the data supporting the tolerogenic role of HLA-G in organ transplantation, the various factors influencing its expression, and the introduction of novel humanized mouse models that are one of the best approaches to assess the utility of HLA-G as a therapeutic tool in organ transplantation.     

Novel BRCA2 pathogenic genotype and breast cancer phenotype discordance in monozygotic triplets

BRCA1/2 genes with high-penetrance are tumor suppressor and tumor susceptibility genes that play important roles in the homologous recombination mechanism in DNA repair and increase breast cancer risk. Variants in BRCA1 or BRCA2 are the main causes of familial and early-onset breast cancer. This study investigated pathogenic variant belonging to the BRCA2 gene splice region in monozygotic triplets. A 44-year-old woman was diagnosed with breast cancer when she was 32 years old. Her monozygotic sister had a history of breast cancer. No malignancy was detected in the third one of the monozygotic triplets. Sanger sequencing was used to evaluate the BRCA1/2 gene status of the patient and family members. It was figured out that they had the same genetic variant, a heterozygous germ-line splice region variant (c.7008-1G > C) in the BRCA2 gene. This novel splice region variant may be a new pathogenic variant of the BRCA2 gene. Its association with breast cancers needs to be further verified in more patient cases.     

Antigen presentation in SARS-CoV-2 infection: the role of class I HLA and ERAP polymorphisms

Given the highly polymorphic nature of Human Leukocyte Antigen (HLA) molecules, it is not surprising that they function as key regulators of the host immune response to almost all invading pathogens, including SARS-CoV-2, the etiological agent responsible for the recent COVID-19 pandemic. Several correlations have already been established between the expression of a specific HLA allele/haplotype and susceptibility/progression of SARS-CoV-2 infection and new ones are continuously emerging. Protective and harmful HLA variants have been described in both mild and severe forms of the disease, but considering the huge amount of existing variants, the data gathered in such a brief span of time are to some extent confusing and contradictory. The aim of this mini-review is to provide a snap-shot of the main findings so far collected on the HLA-SARS-CoV-2 interaction, so as to partially untangle this intricate yarn. As key factors in the generation of antigenic peptides to be presented by HLA molecules, ERAP1 and ERAP2 role in SARS-CoV-2 infection will be revised as well.     

The role of immune cells in pulmonary hypertension: Focusing on macrophages

Pulmonary hypertension (PH) is a life-threatening pathological state with elevated pulmonary arterial pressure, resulting in right ventricular failure and heart functional failure. Analyses of human samples and rodent models of pH support the infiltration of various immune cells, including neutrophils, mast cells, dendritic cells, B-cells, T-cells, and natural killer cells, to the lungs and pulmonary perivascular regions and their involvement in the PH development. There is evidence that macrophages are presented in the pulmonary lesions of pH patients as first-line myeloid leucocytes. Macrophage accumulation and presence, both M1 and M2 phenotypes, is a distinctive hallmark of pH which plays a pivotal role in pulmonary artery remodeling through various cellular and molecular interactions and mechanisms, including CCL2 and CX3CL1 chemokines, adventitial fibroblasts, glucocorticoid-regulated kinase 1 (SGK1), crosstalk with other immune cells, leukotriene B4 (LTB4), bone morphogenetic protein receptor 2 (BMPR2), macrophage migration inhibitory factor (MIF), and thrombospondin-1 (TSP-1). In this paper, we reviewed the molecular mechanisms and the role of immune cells and responses are involved in PH development. We also summarized the polarization of macrophages in response to different stimuli and their pathological role and their infiltration in the lung of pH patients and animal models.     

Down-regulation of MLLT1 super elongation complex subunit impairs the anti-tumor activity of natural killer cells in esophageal cancer

Natural killer (NK) cells actively participate in anti-tumor immunity and are thus regarded as a promising tool in immunotherapy against esophageal cancer (EC). However, the mechanisms regulating NK cell activation and exhaustion have not been completely elucidated. In this study, we characterized the expression and function of MLLT1 super elongation complex subunit (MLLT1) in esophageal NK cells in a mouse EC model. MLLT1 was down-regulated in esophageal NK cells, especially NK cells expressing both T cell immunoglobulin and mucin-domain containing-3 (TIM-3) and lymphocyte activation gene 3 (LAG-3). In vitro knockdown of MLLT1 in NK cells resulted in significant decreases in the expression of IFN-γ and perforin, as well as impaired NK cell cytotoxicity on tumor cells. Adoptive transfer of MLLT-deficient NK cells into EC-bearing mice showed consistent impairment of NK cell anti-tumor activity, as evidenced by decreases in IFN-γ and perforin but not granzyme B. Furthermore, EC tissue cells, which were enriched from the esophagus of EC-bearing mice, induced down-regulation of MLLT1 in splenic NK cells. This down-regulation was partially restored by a TIM-3 blocking antibody. Therefore, this study indicated that TIM-3 signaling down-regulated MLLT1 in esophageal NK cells, and MLLT1 down-regulation undermined the tumoricidal function of NK cells in EC. Our study unveils a novel mechanism underlying NK cell exhaustion/dysfunction in the EC microenvironment. MLLT1 could be a potential target in future NK cell-mediated immunotherapy against EC.     

Adipose tissue and ovarian aging: Potential mechanism and protective strategies

Ovarian aging occurs approximately 10 years prior to the natural age-associated functional decline of other organ systems. With the increase of life expectancy worldwide, ovarian aging has gradually become a key health problem among women. Therefore, understanding the causes and molecular mechanisms of ovarian aging is very essential for the inhibition of age-related diseases and the promotion of health and longevity in women. Recently, studies have revealed an association between adipose tissue (AT) and ovarian aging. Alterations in the function and quantity of AT have profound consequences on ovarian function because AT is central for follicular development, lipid metabolism, and hormonal regulation. Moreover, the interplay between AT and the ovary is bidirectional, with ovary-derived signals directly affecting AT biology. In this review, we summarize the current knowledge of the complex molecular mechanisms controlling the crosstalk between the AT and ovarian aging, and further discuss how therapeutic targeting of the AT can delay ovarian aging.     

Administration of high titer convalescent anti-SARS-CoV-2 plasma: From donor selection to monitoring recipient outcomes

Early in the SARS-CoV-2 pandemic, convalescent plasma (CP) therapy was proposed as a treatment for severely ill patients. We conducted a CP treatment protocol under the Mayo Clinic Extended Access Program at University Hospital Brooklyn (UHB). Potential donors were screened with a lateral flow assay (LFA) for IgM and IgG antibodies against the SARS-CoV-2 S1 receptor-binding domain (RBD). Volunteers that were LFA positive were tested with an ELISA to measure IgG titers against the RBD. Subjects with titers of at least 1:1024 were selected to donate. Most donors with positive LFA had acceptable titers and were eligible to donate. Out of 171 volunteers, only 65 tested positive in the LFA (38.0%), and 55 (32.2%) had titers of at least 1:1024. Before our donation program started, 31 CP units were procured from the New York Blood Center (NYBC). Among the 31 CP units that were obtained from the NYBC, 25 units (80.6%) were positive in the LFA but only 12 units (38.7%) had titers of at least 1:1024. CP was administered to 28 hospitalized COVID-19 patients. Patients who received low titer CP, high titer CP and patients who did not receive CP were followed for 45 days after presentation. Severe adverse events were not associated with CP transfusion. Death was a less frequent outcome for patients that received high titer CP (>1:1024) 38.6% mortality, than patients that received low titer CP (≤1:1024) 77.8% mortality.     

IL-10-producing memory B regulatory cells as a novel target for HLA-G to prolong human kidney allograft survival

Despite the growing interest in the role of regulatory B cells (Bregs) in autoimmunity, their distinct role and function in kidney transplant outcomes remain elusive. Here, we retrospectively analyzed the proportion of Bregs, transitional Bregs (tBregs) and memory Bregs (mBregs) and their capacity to produce IL-10 in non-rejected (NR) versus rejected (RJ) kidney transplant recipients. In the NR group, we observed a significant increase in the proportion of mBregs (CD19⁺CD24^hiCD27⁺) but no difference in tBregs (CD19⁺CD24^hiCD38⁺), as compared to the RJ group. We also observed a significant increase in IL-10-producing mBregs (CD19⁺CD24^hiCD27⁺IL-10⁺) in the NR group. As our group and others have previously reported a potential role of the human leukocyte antigen G (HLA-G) in human renal allograft survival, notably through IL-10, we then investigated possible crosstalk between HLA-G and IL-10⁺ mBregs. Our ex vivo data suggest a role of HLA-G in enhancing IL-10⁺ mBreg expansion upon stimulation, which further decreased CD3⁺ T cell proliferation capability. Using RNA-sequencing (RNA-seq), we identified potential key signaling pathways involved in HLA-G-driven IL-10⁺ mBreg expansion, such as the MAPK, TNF and chemokine signaling pathways. Together, our study highlights a novel HLA-G-mediated IL-10-producing mBreg pathway that may serve as a therapeutic target to improve kidney allograft survival.     

Expression analysis of immune-regulatory molecules HLA-G,HLA-E and IDO in endometrial cancer

HLA-G has been widely implicated in advanced cancers through different pathways of immunosuppression allowing tumor escape. Contrarily, HLA-E has a controversial role in the tumor escape from the immune system. IDO catabolic enzyme is known to be up-regulated in many tumors types allowing their immune escape. Based on these considerations, we investigated the expression of HLA-G, HLA-E and IDO molecules in endometrial cancer (EC) and their association with prognostic clinicopathologic parameters. Their expression were checked in tumoral and adjacent endometrial tissues. Both HLA-G and IDO immunostaining were significantly increased in EC tissues compared to normal residual endometrial glands (Mann Whitney U-test, p = 0.0001 and p = 0,020 respectively). However, HLA-E was highly expressed in tumoral tissues as well as in normal residual endometrial glands (respectively, 100% and 81.8%). Increased HLA-G expression levels were observed in high histological grade (grade 3), and in the non-endometrioid type 2 EC. Unexpectedly, patients with IDO Low expression had significantly impaired overall survival compared to patients with IDO High (log-rank p = 0.021). Conversely, HLA-E low expression was associated to an improved overall survival EC (log-rank p = 0.004). We concluded that, HLA-G and IDO are highly expressed in EC compared to adjacent normal endometrial tissues, that might be interesting for the EC outcome.     

Molecular histocompatibility beyond Tears: The next generation version

Human Leukocyte Antigens (HLA) matching at the serological level used to serve as the measure of histocompatibility between organ donors and recipients. With advancements in HLA typing methods more precise HLA mismatch assessment tools were developed to measure dissimilarities at the molecular level, collectively referred to as Molecular Mismatch load analysis tools. Currently, several software are aimed at deciphering the dissimilarities using somewhat different immunologic rationales. Our goal, in this review is to provide a basic overview of the different computational approaches, provide clinical cases to contextualize concerns regarding the lack of assessment of immunogenicity, and present our personal view regarding the gaps and the needs of our field.     

Virtual crossmatch for deceased donor kidney transplantation in the United States: A survey of histocompatibility lab directors and transplant surgeons

Virtual crossmatch (VXM) is used as an alternative to or in conjunction with a cell-based physical crossmatch (PXM) for assessing HLA (human leukocyte antigen) compatibility prior to deceased donor kidney transplantation (DDKT). Data on practice patterns and perceptions regarding VXM use in the US are limited. We performed a survey of US HLA directors and transplant surgeons regarding HLA testing and crossmatch strategies. 53 (56 %) HLA directors and 68 surgeons (representing ～ 23 % of US transplant centers) completed the survey. Both groups agreed that VXM could reduce cold ischemia time (CIT), costs and improve allocation efficiency. VXM use increased following the 2021 kidney allocation change. Reducing CIT was the primary reason for favoring VXM over PXM. Preference for VXM reduced as candidates’ panel reactive antibodies increased. Regulations, program policies and limitations of HLA technology were cited as important reasons for preferring PXM over VXM. Surgeons reported similar perceptions, but findings are limited by the low response rate. Finally, half the labs reported lacking specific protocols for VXM use. In conclusion, improved HLA technology and protocols along with changes to institutional procedures and policy regulations are needed for safer expansion of VXM in DDKT.     

Association of polymorphisms of innate immunity-related genes and tuberculosis susceptibility in Mongolian population

BackgroundsGenetic polymorphism of the toll-like receptor 2, 4 (TLR2, TLR4) and natural resistance-associated macrophage protein 1 (NRAMP1) genes may affect host immune response to Mycobacterium tuberculosis (Mtb) and lead to the variation of susceptibility to tuberculosis (TB) in humans. However, the association of single nucleotide polymorphisms (SNP) in these genes and the susceptibility to TB in Mongolian population has not been investigated.MethodsWe conducted a genetic association study including 197 Mongolian TB patients and 217 Mongolian healthy controls in Inner Mongolia, China. DNA of blood samples was extracted and genotyped for 5 SNPs in TLR4, 4 SNPs in TLR2 and 5 SNPs in NRAMP1 by next-generation sequencing. A logistic regression was performed and odds ratios (OR) with 95% confidence intervals (CI) were calculated to estimate the risk at TB by each SNP.ResultsThe most significant locus associated with the susceptibility to TB was TLR4 rs11536889. The frequency for allele C of TLR4 rs11536889 was 16.0% in TB patients and 23.5% in healthy controls, respectively. Rs11536889 C/C genotype of TLR4 was significantly associated with the low susceptibility against TB compared to G/G genotype in the dominant model (OR 0.62, 95% CI 0.41–0.94).ConclusionsThe TLR4 rs11536889 polymorphisms might be an indicative of the low susceptibility to TB in Mongolian population, which provides valuable information for the generation of effective strategy or measurement against TB in Mongolian population.