Explore the vast range of titles available.

Human natural killer (NK) cell-based therapies are under assessment for treating various cancers, but cryopreservation reduces both the recovery and function of NK cells, thereby limiting their therapeutic feasibility. Using cryopreservation protocols optimized for T cells, here we find that ~75% of NK cells die within 24 h post-thaw, with the remaining cells displaying reduced cytotoxicity. Using CRISPR-Cas9 gene editing and confocal microscopy, we find that cryopreserved NK cells largely die via apoptosis initiated by leakage of granzyme B from cytotoxic vesicles. Pretreatment of NK cells with a combination of Interleukins-15 (IL-15) and IL-18 prior to cryopreservation improves NK cell recovery to ~90-100% and enables equal tumour control in a xenograft model of disseminated Raji cell lymphoma compared to non-cryopreserved NK cells. The mechanism of IL-15 and IL-18-induced protection incorporates two mechanisms: a transient reduction in intracellular granzyme B levels via degranulation, and the induction of antiapoptotic genes. Natural killer (NK) cells are assessed for various therapies, but sub-optimal cryopreservation dampens their clinical feasibility. Here the authors show that pretreating human NK cells with IL-15/IL-18 prior to cryopreservation improves NK cell post-thaw viability and functions, potentially via anti-apoptosis gene induction and granzyme B degranulation.

Alveolar macrophages (AM) hold lung homeostasis intact. In addition to the defense against inhaled pathogens and deleterious inflammation, AM also maintain pulmonary surfactant homeostasis, a vital lung function that prevents pulmonary alveolar proteinosis. Signals transmitted between AM and pneumocytes of the pulmonary niche coordinate these specialized functions. However, the mechanisms that guide the metabolic homeostasis of AM remain largely elusive. We show that the NK cell-associated receptor, NKR-P1B, is expressed by AM and is essential for metabolic programming. Nkrp1b −/− mice are vulnerable to pneumococcal infection due to an age-dependent collapse in the number of AM and the formation of lipid-laden AM. The AM of Nkrp1b −/− mice show increased uptake but defective metabolism of surfactant lipids. We identify a physical relay between AM and alveolar type-II pneumocytes that is dependent on pneumocyte Clr-g expression. These findings implicate the NKR-P1B:Clr-g signaling axis in AM-pneumocyte communication as being important for maintaining metabolism in AM. Alveolar macrophages (AM) in the lungs maintain surfactant during homeostasis and respond to infectious pathogens. Here the authors show that in the absence of NKR-P1B, pneumococcal infection is more severe because KO AM have increased rates of lipid surfactant uptake and reduced anti-microbial function.

The interaction between natural killer (NK) cell inhibitory receptors and their cognate ligands constitutes a key mechanism by which healthy tissues are protected from NK cell-mediated lysis. However, self-ligand recognition remains poorly understood within the prototypical NKR-P1 receptor family. Here we report the structure of the inhibitory NKR-P1B receptor bound to its cognate host ligand, Clr-b. NKR-P1B and Clr-b interact via a head-to-head docking mode through an interface that includes a large array of polar interactions. NKR-P1B:Clr-b recognition is extremely sensitive to mutations at the heterodimeric interface, with most mutations severely impacting both Clr-b binding and NKR-P1B receptor function to implicate a low affinity interaction. Within the structure, two NKR-P1B:Clr-b complexes are cross-linked by a non-classic NKR-P1B homodimer, and the disruption of homodimer formation abrogates Clr-b recognition. These data provide an insight into a fundamental missing-self recognition system and suggest an avidity-based mechanism underpins NKR-P1B receptor function. Natural killer (NK) cells eliminate damaged cells, but spare healthy ones by recognizing their expressed ligands via NK inhibitory receptors. Here the authors solve the structure of an NK inhibitory receptor, NKR-P1B, bound to its ligand, Clr-b, with further data suggesting a weak interaction and informing on the basis of missing-self recognition.

For many years, human peripheral blood natural killer (NK) cells have been divided into functionally distinct CD3 − CD56 bright CD16 − and CD3 − CD56 dim CD16 + subsets. Recently, several groups of innate lymphoid cells (ILC), distinct from NK cells in development and function, have been defined in mouse. A signature of genes present in mouse ILC except NK cells, defined by Immunological Genome Project studies, is significantly over-represented in human CD56 bright cells, by gene set enrichment analysis. Conversely, the signature genes of mouse NK cells are enriched in human CD56 dim cells. Correlations are based upon large differences in expression of a few key genes. CD56 bright cells show preferential expression of ILC-associated IL7R (CD127), TNFSF10 (TRAIL), KIT (CD117), IL2RA (CD25), CD27, CXCR3, DPP4 (CD26), GPR183 , and MHC class II transcripts and proteins. This could indicate an ontological relationship between human CD56 bright cells and mouse CD127 + ILC, or conserved networks of transcriptional regulation. In line with the latter hypothesis, among transcription factors known to impact ILC or NK cell development, GATA3 , TCF7 (TCF-1), AHR , SOX4, RUNX2 , and ZEB1 transcript levels are higher in CD56 bright cells, while IKZF3 (AIOLOS), TBX21 (T-bet), NFIL3 (E4BP4), ZEB2 , PRDM1 (BLIMP1), and RORA mRNA levels are higher in CD56 dim cells.

Background. Mammalian hibernation in thirteen-lined ground squirrels ( Ictidomys tridecemlineatus ) is characterized by dramatic changes on a physiological and molecular level. During hibernation, mammalian hearts show a propensity to hypertrophy due to the need for increasing contractility to pump colder and more viscous blood. While cardiac hypertrophy is quite often a process characterized by decompensation, the ground squirrel studied is an excellent model of cardiac plasticity and cardioprotection under conditions of hypothermia and ischemia. The forkhead box O (Foxo) family of proteins and myogenin (MyoG) are transcription factors that control protein degradation and muscle atrophy by regulating the expression of the E3 ubiquitin ligases, MAFbx and MuRF1. These ligases are part of the ubiquitin proteasome system by transferring ubiquitin to proteins and targeting these proteins for degradation. Regulation of Foxo1 and 3a occurs through phosphorylation at different residues. The threonine-24 (Thr-24) and serine-319 (Ser-319) residues on Foxo1, and the Thr-32 residue on Foxo3a are phosphorylated by Akt, leading to cytoplasmic localization of Foxo. We propose that the described mechanism contributes to the changes taking place in cardiac muscle throughout hibernation. Methods. Total and phosphorylated protein levels of Foxo1 and Foxo3a, as well as total protein levels of MyoG, MAFbx, and MuRF1, were studied using immunoblotting. Results. Immunoblotting results demonstrated upregulations in Foxo1 and Foxo3a total protein levels (1.3- and 4.5-fold increases relative to euthermic control, for Foxo1 and 3a respectively) during late torpor, and protein levels remained elevated throughout the rest of torpor and at interbout arousal. We also observed decreases in inactive, phosphorylated Foxo1 and 3a proteins during throughout torpor, where levels of p-Foxo1 Ser 319 and Thr 24 , as well as p-Foxo3a Thr 32 decreased by at least 45% throughout torpor. MyoG was upregulated only during late torpor by 2.4-fold. Protein levels of MAFbx and MuRF1 increased in late torpor as well as during early arousal by as much as 2.8-fold, and MAFbx levels remained elevated during interbout arousal, whereas MuRF1 levels returned to control levels. Discussion. The present results indicate that upregulation and activation of Foxo1 and 3a, in addition to the increase in MyoG levels at late torpor, may be upregulating the expression of MAFbx and MuRF1. These findings suggest that there is activation of the ubiquitin proteasome system (UPS) as ground squirrels arouse from torpor. Therefore, the signalling pathway involving MyoG, and the E3 ligases MAFbx and MuRF1, plays a significant role in cardiac muscle remodelling during hibernation. These findings provide insights into the regulation of protein degradation and turnover in the cardiac muscle of a hibernator model.

Helper-type innate lymphoid cells (ILC) play an important role in intestinal homeostasis. Members of the NKR-P1 gene family are expressed in various innate immune cells, including natural killer (NK) cells, and their cognate Clr ligand family members are expressed in various specialized tissues, including the intestinal epithelium, where they may play an important role in mucosal-associated innate immune responses. In this study, we show that the inhibitory NKR-P1B receptor, but not the Ly49 receptor, is expressed in gut-resident NK cells, ILC, and a subset of γδT cells in a tissue-specific manner. ILC3 cells constitute the predominant cell subset expressing NKR-P1B in the gut lamina propria. The known NKR-P1B ligand Clr-b is broadly expressed in gut-associated cells of hematopoietic origin. The genetic deletion of NKR-P1B results in a higher frequency and number of ILC3 and γδT cells in the gut lamina propria. However, the function of gut-resident ILC3, NK, and γδT cells in NKR-P1B-deficient mice is impaired during gastrointestinal tract infection by Citrobacter rodentium or Salmonella typhimurium, resulting in increased systemic bacterial dissemination in NKR-P1B-deficient mice. Our findings highlight the role of the NKR-P1B:Clr-b recognition system in the modulation of intestinal innate immune cell functions.

Primary graft dysfunction (PGD) limits clinical benefit after lung transplantation, a life-prolonging therapy for patients with end-stage disease. PGD is the clinical syndrome resulting from pulmonary ischemia-reperfusion injury (IRI), driven by innate immune inflammation. We recently demonstrated a key role for NK cells in the airways of mouse models and human tissue samples of IRI. Here, we used 2 mouse models paired with human lung transplant samples to investigate the mechanisms whereby NK cells migrate to the airways to mediate lung injury. We demonstrate that chemokine receptor ligand transcripts and proteins are increased in mouse and human disease. CCR5 ligand transcripts were correlated with NK cell gene signatures independently of NK cell CCR5 ligand secretion. NK cells expressing CCR5 were increased in the lung and airways during IRI and had increased markers of tissue residency and maturation. Allosteric CCR5 drug blockade reduced the migration of NK cells to the site of injury. CCR5 blockade also blunted quantitative measures of experimental IRI. Additionally, in human lung transplant bronchoalveolar lavage samples, we found that CCR5 ligand was associated with increased patient morbidity and that the CCR5 receptor was increased in expression on human NK cells following PGD. These data support a potential mechanism for NK cell migration during lung injury and identify a plausible preventative treatment for PGD.

Innate lymphoid cells (ILCs) are tissue-resident sentinels that are essential for early host protection from pathogens at initial sites of infection. However, whether pathogen-derived antigens directly modulate the responses of tissue-resident ILCs has remained unclear. In the present study, it was found that liver-resident type 1 ILCs (ILC1s) expanded locally and persisted after the resolution of infection with mouse cytomegalovirus (MCMV). ILC1s acquired stable transcriptional, epigenetic and phenotypic changes a month after the resolution of MCMV infection, and showed an enhanced protective effector response to secondary challenge with MCMV consistent with a memory lymphocyte response. Memory ILC1 responses were dependent on the MCMV-encoded glycoprotein m12, and were independent of bystander activation by proinflammatory cytokines after heterologous infection. Thus, liver ILC1s acquire adaptive features in an MCMV-specific manner. O’Sullivan and colleagues show that liver-resident type 1 ILCs have enhanced protective effector responses to secondary challenge with mouse cytomegalovirus, dependent on the viral glycoprotein m12.

Recent green manufacturing demands have boosted the development of new biodegradable lubricants to replace petroleum-based lubricants. In this regard, water-based lubricants have been at the vanguard of recent research for a wide range of industrial applications, including metalworking fluids (MWFs). In this work, we present an experimental investigation on the performance of novel green MWFs based on aqueous nopal mucilage solutions. For this, fully biodegradable solutions with different mucilage concentrations (2.29, 4.58, and 6.85 mg/mL) were evaluated in terms of rheological, tribological, thermal stability, and turning (minimum quantity lubrication) performance and compared to a commercial semisynthetic oil-based MWF (Cimstar 60). Mucilage solutions exhibited viscoelastic shear-thinning behavior, which was enhanced along with mucilage concentration. The solution with the highest mucilage content studied resulted in the lowest wear, friction, and temperature in comparison to the other solutions and neat water in extreme pressure four-ball tests and a similar level of lubricity as compared to the commercial MWF in cutting tests. This performance is associated with the enhanced viscosity and elasticity of the solution, as well as the contents of lipids with fatty acids in the mucilage. Overall, the present results reveal the relevance of the viscoelastic behavior of the lubricant, elasticity in particular, in lubrication processes and point to nopal mucilage as an effective green additive to produce innocuous MWFs.