Human NK cells,their receptors and function

NK cells are cytotoxic components of innate lymphoid cells (ILC) that provide a first line of defense against viral infections and contribute to control tumor growth and metastasis. Their function is finely regulated by an array of HLA-specific and non-HLA-specific inhibitory and activating receptors which allow to discriminate between healthy and altered cells. Human NK cells gained a major attention in recent years because of the important progresses in understanding their biology and of some promising data in tumor therapy. In this review, we will outline well-established issues of human NK cells and discuss some of the open questions, debates, and recent advances regarding their origin, differentiation, and tissue distribution. Newly defined NK cell specializations, including the impact of inhibitory checkpoints on their function, their crosstalk with other cell types, and the remarkable adaptive features acquired in response to certain virus infections will also be discussed.     

Developmental changes of HT7 expression in the microvessels of the chick embryo brain

The neurothelin/HT7 antigen is a chick-specific, cell-surface glycoprotein expressed by the brain endothelial cells and widely utilized in experimental studies as a marker of barrier-provided vessels. Previous immunohistochemical studies have demonstrated that HT7 is already expressed in the embryonic brain vessels and that it is first detectable on embryonic day 10 and developmentally regulated. In the present study, the vascular expression of HT7 was investigated in different regions of the central nervous system from the 5th day right up to the latest stage of the chick embryo development. The study was carried out utilizing a monoclonal antibody anti-HT7, which was detected by both enzymatic and fluorescent immunohistochemical methods. The observations demonstrated the presence of HT7-stained vessels as early as embryonic day 6 in the rhombencephalon and mesencephalon, and at embryonic day 9 in the prosencephalon. Regional differences were also evidenced within the rhombencephalon and mesencephalon, since the endothelial antigen HT7 was expressed earlier in the brain stem (tegmentum of the medulla oblongata, pons and mesencephalon) than in the cerebellum and optic tectum. The caudo-cranial and ventro-dorsal gradients of HT7 expression were temporally and spatially related to the development of the brain vessels. The early detection of HT7 staining in the choroid plexus epithelium and perineural vessel endothelium, sites of the blood-cerebrospinal fluid barrier and pial barrier, respectively, has confirmed this antigen to be a precocious marker for all the barrier systems in the brain.     

The plexin C1 receptor promotes acute inflammation

Acute inflammation is the pathophysiological basis of important clinical conditions associated with organ failure. The initial inflammatory response is controlled by the chemokine system, yet recent data have indicated that the neuronal guidance cues are significantly involved in the orchestration of this process. Previous work has shown the proinflammatory capacity of the guidance cue semaphorin (Sema) 7a, but the role of one of its target receptors, the plexin C1 (PLXNC1) receptor is to date unknown. We report here that PLXNC1 is expressed outside the nervous system and induced during acute inflammation. PLXNC1^?/? mice with C57BL/6 background demonstrated decreased inflammatory responses during zymosan A (ZyA)‐induced peritonitis. Subsequent in vivo studies revealed altered rolling, adhesion, and transmigration properties of PLXNC1^?/? leukocytes. Blockade of PLXNC1 was associated with attenuated chemotactic transendothelial migration properties in vitro. Studies in chimeric mice revealed that hematopoietic PLXNC1^?/? animals demonstrated an attenuated inflammatory response. To probe the therapeutic potential of PLXNC1 we treated C57BL/6 WT mice with an anti‐PLXNC1 antibody and a PLXNC1 binding peptide. Both of these interventions significantly dampened ZyA‐induced peritonitis. These results implicate an important role of PLXNC1 during an acute inflammatory response and indicate PLXNC1 as a potential target for the control of conditions associated with acute inflammation.     

Preclinical relevance of probiotics in type 2 diabetes: A systematic review

Type 2 diabetes (T2DM) is among the most prevalent metabolic diseases in the world and may result in several long‐term complications. The crosstalk between gut microbiota and host metabolism is closely related to T2DM. Currently, fragmented data hamper defining the relationship between probiotics and T2DM. This systematic review aimed at investigating the effects of probiotics on T2DM in animal models. We systematically reviewed preclinical evidences using PubMed/MEDLINE and Scopus databases, recovering 24 original articles published until September 27th, 2019. This systematic review was performed according to PRISMA guidelines. We included experimental studies with animal models reporting the effects of probiotics on T2DM. Studies were sorted by characteristics of publications, animal models, performed analyses, probiotic used and interventions. Bias analysis and methodological quality assessments were examined through the SYRCLE's Risk of Bias tool. Probiotics improved T2DM in 96% of the studies. Most studies (96%) used Lactobacillus strains, and all of them led to improved glycaemia. All studies used rodents as models, and male animals were preferred over females. Results suggest that probiotics have a beneficial effect in T2DM animals and could be used as a supporting alternative in the disease treatment. Considering a detailed evaluation of the reporting and methodological quality, the current preclinical evidence is at high risk of bias. We hope that our critical analysis will be useful in mitigating the sources of bias in further studies.     

Molecular analysis of ANT1, TWINKLE and POLG in patients with multiple deletions or depletion of mitochondrial DNA by a dHPLC-based assay

ANT1, TWINKLE and POLG genes affect mtDNA stability and are involved in autosomal dominant PEO, while mutations in POLG are responsible for numerous clinical presentations, including autosomal recessive PEO, sensory ataxic neuropathy, dysarthria and ophthalmoparesis (SANDO), spino-cerebellar ataxia and epilepsy (SCAE) or Alpers syndrome. In this study, we report on the mutational analysis of ANT1, TWINKLE and POLG genes in 15 unrelated patients, using a dHPLC-based protocol. This series of patients illustrates the large array of clinical presentations associated with mtDNA stability defects, ranging from isolated benign PEO to fatal Alpers syndrome. A total of seven different mutations were identified in six of 15 patients (40%). Six different recessive mutations were found in POLG, one in TWINKLE while no mutation was identified in ANT1. Among the POLG mutations, three are novel and include two missense and one frameshift changes. Seventeen neutral changes and polymorphisms were also identified, including four novel neutral polymorphisms. Overall, this study illustrates the variability of phenotypes associated with mtDNA stability defects, increases the mutational spectrum of POLG variants and provides an efficient and reliable detection protocol for ANT1, TWINKLE and POLG mutational screening.     

Relaxing effect of CEDO 8956 and hydralazine HCl in cultured smooth muscle cells versus pericytes: a preliminary study

BACKGROUND: It hs been reported that some glaucoma patients have deficient endothelial nitric oxide production. The effect of the presupposed nitrovasodilators CEDO 8956 and hydralazine hydrochloride (HCl) on bovine retinal microcirculation pericytes and ophthalmic artery smooth muscle cells are investigated. METHODS: Cells were cultured on silicone membranes and their contractile tone observed by phase contrast inverted microscopy before and after exposure by fluid exchange to different drugs at various concentrations. Experiments were conducted with pericytes in the absence (control) or in the presence (10 nM - 0.1 mM) of CEDO 8956, hydralazine HCl, or sodium nitroprusside (SNP). Experiments were conducted with smooth muscle cells in the absence (control) or in the presence (0.1 mM) of CEDO 8956, or hydralazine HCl. RESULTS: In comparison to control (- 0.56 +/- 10 %), pericytes were significantly relaxed by SNP (100 +/- 0 %, p < 0.001), but not by CEDO 8956 (9.2 +/- 15.4 %) or hydralazine HCl (20.6 +/- 4.4 %). In comparison to control (1.64 +/- 5.3 %), smooth muscle cells were significantly relaxed by CEDO 8956 (46.2 +/- 12.4 %, p < 0.05) and hydralazine HCl (54.9 +/- 9.1 %, p < 0.001). CONCLUSIONS: These results suggest a possible heterogeneity between cultured bovine microcirculation pericytes and ophthalmic artery vascular smooth muscle cells in the relaxing response to CEDO 8956 and hydralazine HCl. Apparently, these two drugs might not be first choice candidates in order to attempt to try to selectively improve circulation in the retina or the optic nerve head capillary network.     

Phase II trial of interferon-alpha-2a plus psolaren with ultraviolet light A in patients with cutaneous T-cell lymphoma

PURPOSE: To evaluate the efficacy and side effects of psolaren with ultraviolet light A (PUVA) and interferon-alpha-2a (IFN-alpha-2a) in patients with mycosis fungoides (MF) and Sézary syndrome (SS). PATIENTS AND METHODS: From May 1993 to January 1999, 63 symptomatic patients with all stages of MF and SS were treated in a prospective Phase II trial with systemic escalating doses of IFN-alpha-2a combined with PUVA for 1 year, followed by indefinite PUVA maintenance in complete responding patients. RESULTS: Sixty-three patients were enrolled (Stage IA, n = 6; IB, n = 37; IIA, n = 3; IIB, n = 3; III, n = 12; IVA, n = 2). Ten patients had received previous therapy. The median follow-up duration for the entire cohort is 37 months. Of 63 patients, 51 achieved a complete response (CR; 74.6%) or partial response (PR; 6%) to therapy. The median response duration is 32 months. The 5-year overall survival rate is 91% and the 5-year disease-free survival rate is 75%. No life-threatening side effects were observed. Five patients stopped IFN-alpha-2a therapy due to toxicity. Eighty-four percent of the patients received more than 75% of the planned dose (12 million units three times a week). CONCLUSIONS: This combination of IFN-alpha-2a and phototherapy is an effective and safe therapy for patients with symptomatic MF.     

Adenosine increases human platelet levels of cGMP through nitric oxide: possible role in its antiaggregating effect

Adenosine is an endogenous antiaggregating substance that influences the platelet responses through specific A-type receptors that activate adenylate cyclase increasing the levels of 3',5'-cyclic adenosine monophosphate (cAMP). In this study, we investigated whether adenosine can also influence the levels of 3',5'-cyclic guanosine monophosphate (cGMP) and decrease the aggregating response of human platelets to adenosine-5-diphosphate (ADP) through this nucleotide. In platelet samples from healthy volunteers, we evaluated the effect of adenosine on ADP-induced aggregation and cyclic nucleotide synthesis. Some experiments were repeated in the presence of dipyridamole (inhibitor of adenosine uptake and phosphodiesterase activity), N(G)-monomethyl-L-arginine (L-NMMA, nitric synthase inhibitor), ionomycin (calcium ionophore), and ambroxol (2-amino-3,5-dibromo-N-[trans-4-hydroxycyclohexyl]benzylamine, inhibitor of nitric oxide (NO)-dependent activation of guanylate cyclase). Adenosine decreased the response to ADP in a concentration-dependent way (analysis of variance, ANOVA: P<.0001): cAMP levels increased from 30.0 +/- 2.0 (control) to 46.0 +/- 3.0 pmol/10(9) platelets (in the presence of 15 mumol/l adenosine) and cGMP levels increased from 5.6 +/- 1.0 (control) to 10.9 +/- 2.0 pmol/10(9) platelets (in the presence of 15 mumol/l adenosine). Also, nucleotide levels measured at the end of aggregation were higher in platelet samples exposed to adenosine than in controls. Dipyridamole at 40 mumol/l slightly increased adenosine's effects on both nucleotides. L-NMMA blunted the effect of adenosine on cGMP both in unstimulated samples and in aggregated platelets without any effect on cAMP synthesis. Platelet exposure to L-NMMA and ambroxol partially prevented adenosine's effect on ADP-induced aggregation. In conclusion, adenosine, which enhances intraplatelet cAMP levels, was determined to also cause an increase in cGMP concentrations through a mechanism that involves NO synthesis. This effect plays a direct role in the adenosine-induced antiaggregation.