Pathologic cardiac hypertrophy requires increased protein synthesis, but the mechanosensors that link membrane stretch to translational control remain poorly understood. Polycystin-1 (PC1), encoded by PKD1 , has been proposed as a cardiac mechanosensor, with its C-terminal tail (PC1-CT) promoting hypertrophy in rodent cardiomyocytes. However, its subcellular localization and downstream signaling remain incompletely defined, especially in human cardiomyocytes. Here, we examined endogenous PC1 C-terminus localization and the effects of adenoviral PC1-CT overexpression in human iPSC-derived ventricular cardiomyocytes (hiPSC-CMs) and adult mouse ventricular myocytes. Immunofluorescence revealed a striking striated pattern for both endogenous PC1 C-terminus (detected with a PC1-CT antibody) and the overexpressed PC1-CT fragment. In hiPSC-CMs, the PC1 C-terminus localized between the α-actinin bands. In contrast, in adult cardiomyocytes, the overexpressed protein colocalized with α-actinin and desmin, suggesting that PC1-CT sarcomeric distribution depends on cardiomyocyte maturation. We performed RNA-seq to assess transcriptional responses downstream of PC1-CT overexpression in hiPSC-CMs relative to LacZ controls. Gene Set Enrichment Analysis (GSEA) revealed enrichment of gene sets related to ribosome biogenesis, RNA processing, and protein synthesis, while classical hypertrophic markers remained unchanged. Pathway analysis suggested increased PI3K activity. PC1-CT overexpression increased phosphorylation of Akt, ERK, S6K1, and ribosomal protein S6 without altering 4EBP1 phosphorylation, suggesting preferential activation of the mTOR-S6K1-S6 branch. Pharmacological studies showed that pan-PI3K inhibition abolished S6 phosphorylation, whereas MEK blockade did not affect it; pertussis toxin and PI3Kγ-selective inhibitors also did not affect S6, suggesting a G i/o -independent PI3K/Akt signaling driving mTOR-S6K1-S6 activation. Collectively, these data identify a sarcomere-associated pool of PC1-CT that engages PI3K-Akt-mTOR-S6K1-S6 signaling to enhance transcriptional programs related to ribosome biogenesis and protein synthesis, without activating a canonical hypertrophic gene program. These findings reveal a mechanistic link between PC1-CT and cardiomyocyte growth.
Ferritin dysregulation is implicated in numerous pathological conditions; however, its role in autosomal dominant polycystic kidney disease (PKD) remains poorly understood. Ferritin expression is increased in cyst-lining epithelial cells and macrophages in both PKD mouse and human kidneys. To investigate the functional significance of ferritin/iron homeostasis in disease progression, we generated conditional knockout of ferritin heavy chain (FTH) in collecting duct or myeloid lineage cells of PKD mice. FTH deletion in either cell type did not impact renal cyst growth. Notably, loss of FTH expression was accompanied by compensatory upregulation of ferritin light chain (FTL) in both models. To assess the effects of systemic ferritin infusion, we administered ferritin (iron replete), apoferritin (iron deplete), or phosphate-buffered saline (PBS; vehicle control) to PKD mice. Ferritin but not apoferritin infusion led to splenomegaly in wild-type (WT) and PKD mice, with no obvious alterations in cyst progression. Notably, ferritin infusion led to focal accumulation of ferritin in macrophage-enriched regions within the kidneys of PKD, but not WT mice. Consistent with this, elevated iron was detected in the kidneys of ferritin-treated PKD mice but not in wild-type controls, suggesting dysfunctional ferritin trafficking. Mechanistically, we observed increased uptake of ferritin and dysregulation of ferritin receptors by renal cystic epithelial cells of PKD patients. Ferritin-enriched areas were positive for heme oxygenase 1 and represented high oxidative stress and fibrosis. Collectively, these findings demonstrate a disruption in ferritin handling and iron homeostasis in PKD. This altered iron trafficking promotes localized oxidative stress and fibrosis, contributing to disease progression.NEW & NOTEWORTHY Ferritin dysregulation in autosomal dominant polycystic kidney disease (ADPKD) reveals a novel disease mechanism. Although ferritin heavy chain deletion does not affect cyst growth, polycystic kidney disease (PKD) kidneys show compensatory ferritin light chain upregulation and abnormal ferritin trafficking. Iron-loaded ferritin accumulates in macrophage-rich regions, increasing oxidative stress and fibrosis. Enhanced ferritin uptake and receptor dysregulation in cystic epithelial cells highlight disrupted iron homeostasis as a previously unrecognized contributor to ADPKD progression.
Most cases of autosomal dominant polycystic kidney disease (ADPKD) are caused by mutations in PKD1, which reduce polycystin-1 (PC1) levels below a critical functional threshold. Normalizing PC1 dosage mitigates disease progression; therefore, we sought to develop a CRISPR activation (CRISPRa) strategy to transcriptionally upregulate endogenous PKD1. We systematically screened multiple single-guide RNAs using an EGFP-reporter platform and identified potent candidates targeting the proximal PKD1 promoter in mouse and human cell models. Our results demonstrate that CRISPRa effectively increased endogenous Pkd1 mRNA in the mouse collecting duct-derived Pkd1 RC/- cell model and in the primary renal epithelial cells from PKD mice. In Pkd1 RC/- cells, CRISPRa of Pkd1 increased PC1 protein levels and significantly reduced cell proliferation and in vitro cyst formation in 3D cultures. Mechanistically, Pkd1 activation improved mitochondrial membrane potential, reduced dependency on aerobic glycolysis, and corrected signaling pathways involved in cystogenesis, specifically reducing intracellular cAMP, cMyc, pCreb, and pErk levels, while increasing pYap1 levels. We confirmed the translational potential of this platform by successfully activating PKD1 in primary renal epithelial cells from human kidneys. We observed a heterogeneous response across both normal and ADPKD patient-derived donor lines, with significant upregulation achieved in two of the tested cell preparations. These findings provide a compelling proof-of-concept that CRISPRa-mediated gene augmentation can increase PC1 levels, establishing a foundation for promising gene therapies aimed at successfully suppressing the pathogenic features of ADPKD.
Tumors foster an immunosuppressive microenvironment to evade the antitumor immune response. However, the influence of intratumoral immunosuppressive steroids on tumor-infiltrating natural killer (NK) cells and their implications for effective immunotherapy has remained largely unexplored. Here, we report that the functional enrichment of glucocorticoid cortisol signaling in the lung tumor microenvironment (TME) impairs NK cell anti-tumor cytotoxicity and exacerbates hypoxic stress. Cancer-associated fibroblasts (CAFs) and macrophages convert inactive cortisone to active cortisol, while T cells, fibroblasts, myeloid cells, macrophages, and cancer cells contribute to de novo steroid biosynthesis, collectively establishing a steroid-rich niche. Pharmacological inhibition of the glucocorticoid receptor (GR) in vivo alleviates cortisol-mediated immune suppression, resulting in reduced tumor growth and enhanced cytotoxicity of tumor-infiltrating NK cells. To overcome the cortisol-induced dysfunction of solid tumor targeting immunotherapy, we engineered chimeric antigen receptor (CAR) -NK cells specific to the Carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) (highly expressed in lung tumors) and rendered them cortisol-resistant by genetic deletion of the cortisol receptor gene NR3C1. In cortisol-rich niches, cortisol-resistant CAR-NK cells sustained antitumor cytotoxicity. Mechanistically, NR3C1 deletion relieved cortisol-mediated suppression of PI3K-AKT-NF-κB signaling, restored anti-tumor activity, and markedly reduced hypoxic stress. In lung metastasis models, cortisol-resistant CAR-NK cells achieved superior tumor control and significantly reduced tumor burden compared with conventional CAR-NK cells. Together, these findings identify local cortisol signaling as a critical barrier to solid tumor immunotherapy and establish cortisol-resistant CAR-NK cells as a promising strategy for targeting steroidogenic solid tumors, which can be combined with therapeutic glucocorticoids.
Glucocorticoids are potent immune regulators, yet how cortisol controls human CD8 T cell function remains poorly defined. Here, we show that cortisol reshapes the transcriptional landscape of human CD8 T cells through cooperation between the glucocorticoid receptor (GR) and RUNX transcription factors. Integrative RNA sequencing (RNA-seq) and chromatin immunoprecipitation followed by sequencing (ChIP-seq) analyses identified genome-wide cortisol-responsive immunoregulatory genes, and NR3C1 deletion confirmed GR dependency. GR chromatin occupancy was enriched at RUNX motifs rather than canonical glucocorticoid response elements, and co-immunoprecipitation confirmed a ligand-dependent interaction between GR and RUNX3, requiring the N-terminal activation function-1 (AF1) domain of GR and the C-terminal region of RUNX3. Single-cell transcriptomic analyses across multiple solid tumors revealed consistent enrichment of GR-RUNX co-regulated genes in tumor-infiltrating CD8 T cells, predominantly within the predysfunctional state. These findings identify RUNX3 as a critical non-canonical GR partner and uncover a therapeutically actionable mechanism by which endogenous glucocorticoids drive CD8 T cell dysfunction in human cancer.
Abstract Glioblastoma (GBM) remains a devastating disease with few meaningful therapeutic advances over the past three decades. Dendritic cell (DC) vaccination is a promising immunotherapeutic strategy for GBM, but its efficacy is limited by the clinical use of dexamethasone to control cerebral oedema and associated symptoms. Here we show that steroid signalling is a central regulator of DC dysfunction in GBM. Through targeted metabolomics of primary GBM samples, we identified a steroid-rich tumour microenvironment in which dexamethasone is present at high levels. Across bulk and single-cell transcriptomic and epigenomic datasets, NR3C1 emerged as the dominant steroid receptor in GBM immune cells and was negatively associated with activated DC states. In patient-derived DCs, dexamethasone altered NR3C1 chromatin occupancy, induced broad transcriptional and chromatin remodelling, and suppressed co-stimulatory antigen-presentation and cytokine programmes. DC-specific deletion of Nr3c1 restricted syngeneic glioblastoma growth, enhanced DC activation, promoted cytotoxic CD8 + T cell responses and remodelled myeloid states in vivo. In GBM patient-derived DCs, pharmacological or non-viral CRISPR-mediated disruption of NR3C1 restored inflammatory, antigen presentation and T cell-stimulatory programmes, enhanced antigen-specific CD8 + T cell priming, and improved tumour lysate-loaded DC vaccination. Together, these findings identify glucocorticoid signalling as a key barrier to DC immunotherapy in GBM and establish NR3C1-targeted, steroid-resistant DCs as a potential therapeutic strategy.
Pancreatic cancer (PC) represents one of the biggest challenges in terms of cancer treatment, mainly due to its continuously rising incidence, advanced stage at time of diagnosis, and dismal 5-year overall survival, which has not improved in recent decades despite the major advances made in oncological therapies. The limited progress in developing more effective therapies is, in part, attributable to the vast desmoplastic stroma present in PC. Additionally, immunosuppressive steroid-signalling has recently been shown to aid the development and metastasis of various tumour types. Therefore, we sought to explore whether local steroidogenesis and steroid signalling within the tumour microenvironment (TME) play a role in pancreatic cancer development. Reanalysis of publicly available datasets, including single cell RNA sequencing, as well as in vivo metastatic pancreatic ductal adenocarcinoma (PDAC) mouse models, allowed us to identify Hsd11b1 as the key enzyme responsible for locally elevated levels of the immunosuppressive glucocorticoid hormone, corticosterone. We identified fibroblasts as the major Hsd11b1-expressing populations in the pancreatic TME. Specifically, in mice, Hsd11b1 expression is primarily observed in iCAFs. Additionally, we found that patients with higher HSD11B1 expression present an increased mortality rate as well as an enriched fibrotic signature and inhibited immune activity. Collectively, these findings suggest that Hsd11b1 upregulation in iCAFs could be aiding PDAC development by promoting the activation of glucocorticoids directly in the TME. The presence of glucocorticoids inhibits inflammation and could also be enhancing local fibrosis by autocrine signalling in the fibroblast population. Given the urgent need for effective treatments in this fatal disease, targeting HSD11B1 represents a promising therapeutic strategy to overcome the immunosuppressive desmoplastic barrier and improve patient outcomes in pancreatic cancer. ### Competing Interest Statement The authors have declared no competing interest. CRUK, RCCFEL\100095 NSF-BIO/UKRI-BBSRC, BB/V006126/1 MRC, MR/V028995/1
Tumour microenvironments (TME) accumulate immunosuppressive steroids, impairing NK cell anti-tumour immunity. We found glucocorticoid cortisol signalling enrichment in lung TME exacerbates hypoxic stress and impairs NK cell function. Single-cell transcriptomics revealed cancer-associated fibroblasts and macrophages convert inactive cortisone to active cortisol, while T cells, mast cells, and macrophages induce de novo steroid biosynthesis. Inhibiting the glucocorticoid receptor in mice reduced tumour growth and improved NK cell cytotoxicity.To overcome steroid-mediated immunosuppression, we engineered CEACAM5-specific CAR-NK cells with CRISPR-mediated deletion of the glucocorticoid receptor (NR3C1). These cortisol-resistant CAR-NK cells showed enhanced tumour cell killing efficacy, even in the presence of glucocorticoids. This approach offers promising applications against steroidogenic solid tumours and potential use alongside therapeutic glucocorticoids. Our study addresses a critical challenge in CAR-NK cell therapy for lung cancer - the immunosuppressive TME. By targeting CEACAM5, highly expressed in lung tumours, and making CAR-NK cells cortisol-resistant, we’ve developed a novel strategy to enhance the efficacy of immunotherapy in steroid-rich environments. This advancement could significantly improve outcomes for lung cancer patients, addressing limitations of current CAR-NK therapies in solid tumours. The work is supported by CRUK Career Development Fellowship (RCCFEL\100095), NSF-BIO/UKRI-BBSRC project grant (BB/V006126/1), MRC project grant (MR/V028995/1), CRUK Cambridge Centre Cancer Immunology Programme Pump Priming award, and CRUK CC MRes/PhD Studentship. Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)
Chimeric antigen receptor (CAR) T-cell therapy has shown unprecedented success in haematological cancers but faces challenges in solid tumours. Although carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) is differentially expressed in many solid tumours, CEACAM5 CAR T-cells are ineffective. Here, we have studied the interaction of CEACAM5 targeting CAR primary T-cells with colorectal cancer (CRC) cells using fluorescence microscopy. We find that CRC cells glycocalyx is much thicker than the CAR T-cell and likely contributes to immune-escape. Oscillating calcium flux, a signature of non-sustained triggering and decreased killing, was observed when CAR T-cells interacted with CRC, which increased with increasing cell-seeding time. This was because CEACAM5 became increasingly unavailable on the CRC cell monolayer, as revealed by fluorescence imaging. Local proteolytic treatment with trypsin to disrupt the CRC cell monolayer, using a micropipette, increased CEACAM5 availability, decreased glycocalyx thickness, and restored sustained CAR T-cell calcium fluxes, increasing the killing of CRC cells. Our results reveal why CAR T-cells targeting CEACAM5 are ineffective and suggest possible routes for improved therapy. ### Competing Interest Statement The authors have declared no competing interest.
Autosomal dominant polycystic kidney (ADPKD) disease is the commonest genetic cause of kidney failure (affecting 1:800 individuals) and is due to heterozygous germline mutations in either of two genes, PKD1 and PKD2. Homozygous germline mutations in PKHD1 are responsible for autosomal recessive polycystic kidney (ARPKD) disease a rare (1:20,000) but severe neonatal disease. The products of these three genes, PKD1 (polycystin-1 (PC1 4302(3)aa)), PKD2 (polycystin-2 (PC2 968aa)) and PKHD1 (fibrocystin (4074aa)) are all present on extracellular vesicles (EVs) termed, PKD-exosome-like vesicles (PKD-ELVs). PKD-ELVs are defined as 100 nm PC1/PC2/CD133 and fibrocystin positive EVs which are shed into the urine from the apical plasma membrane of proximal tubule (PT) cells. PKD-ELVs are therefore ectosomes and are distinct from classical exosomes from the multivesicular body. PC1, PC2, fibrocystin and exosomal polycystin-1 interacting protein (EPIC, CU062) form a higher order ion channel complex termed the polycystin complex (PCC) on the surface of the PKD-ELV. We hypothesize that the PCC is involved in the generation of the PKD-ELV and is a structural component thereof. The PCC has also been detected on the primary cilium, a hair like 9+0 microtubule based structure present on all cells except hepatocytes. In kidney epithelial cells, the primary cilium protrudes into the lumen of the tubule where it regulates planar cell polarity (PCP) and tubule lumen diameter. Here we present a theory that explains the presence of the PCC on PKD-ELVs and primary cilia as well as other cryptic aspects of ADPKD and ARPKD. We suggest that the fundamental role of the PCC is to assemble PKD-ELVs on the plasma membrane and then shed them into the extracellular space or the lumen of the tubule. The resultant PKD-ELVs can have multiple functions in different biological contexts. One of the roles of the resultant PKD-ELVs is to generate a planar cell polarity (PCP) signaling gradient along kidney tubules in developing or regenerating kidney. This is mediated via an adhesion event between the PKD-ELV and primary cilium. Defects in the primary cilium or PKD-ELV assembly lead to cystogenesis, the major feature of ADPKD. The other important role for the PCC dependent PKD-ELV is the detection, packaging and extrusion of defective mitochondria. The PKD-ELV is also critical in the transfer of mRNA and miRNAs between cells and as a vector for extracellular proteinases and hyaluronidases involved in tissue remodeling. A PKD-ELV centric view of polycystic disease (EV theory) can explain the requirement for primary cilium function in ADPKD (where the primary cilium is the PKD-ELV receptor), the observation of defective mitochondria in the disease, the abnormalities detected in the extracellular matrix (ECM) as well as the resistance to carcinoma noted in ADPKD patients and individuals carrying PKHD1 mutations, see graphical abstract.
Background:Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutations in the PKD1 and PKD2 genes, and often progresses to kidney failure. ADPKD progression is not uniform among patients, suggesting that factors secondary to the PKD1/2 gene mutation could regulate the rate of disease progression. Here we tested the effect of circadian clock disruption on ADPKD progression. Circadian rhythms are regulated by cell-autonomous circadian clocks composed of clock proteins. BMAL1 is a core constituent of the circadian clock. Methods:To disrupt the circadian clock, we deleted Bmal1 gene in the renal collecting ducts of the Pkd1 RC/RC (RC/RC) mouse model of ADPKD (RC/RC; Bmal1 f/f ; Pkhd1 cre , called DKO mice), and in Pkd1 knockout mouse inner medullary collecting duct cells ( Pkd1Bmal1 KO mIMCD3 cells). Only male mice were used. Results:Human nephrectomy ADPKD kidneys and Pkd1 KO mIMCD3 cells showed reduced Bmal1 gene expression compared to normal controls. When compared to RC/RC kidneys, DKO kidneys showed significantly altered clock gene expression, increased cyst growth, cell proliferation, apoptosis and fibrosis. DKO kidneys also showed increased lipogenesis and cholesterol synthesis-related gene expression, and increased tissue triglyceride levels compared to RC/RC kidneys. Similarly, in vitro, Pkd1Bmal1 KO cells showed altered clock genes, increased lipogenesis and cholesterol synthesis-related genes, and reduced fatty-acid oxidation-related gene expression compared to Pkd1KO cells. The Pkd1Bmal1 KO cells showed increased cell proliferation compared to Pkd1KO cells, which was rescued by pharmacological inhibition of lipogenesis. Conclusion:Renal collecting duct specific Bmal1 gene deletion disrupts the circadian clock and triggers accelerated ADPKD progression by altering lipid metabolism-related gene expression. Key points:Lack of BMAL1, a circadian clock protein in renal collecting ducts disrupted the clock and increased cyst growth and fibrosis in an ADPKD mouse model.BMAL1 gene deletion increased cell proliferation by increasing lipogenesis in kidney cells.Thus, circadian clock disruption could be a risk factor for accelerated disease progression in patients with ADPKD.
B cells play a central role in humoral immunity but also have antibody-independent functions. Studies to date have focused on B cells in blood and secondary lymphoid organs but whether B cells reside in non-lymphoid organs (NLO) in homeostasis is unknown. Here we identify, using intravenous labeling and parabiosis, a bona-fide tissue-resident B cell population in lung, liver, kidney and urinary bladder, a substantial proportion of which are B-1a cells. Tissue-resident B cells are present in neonatal tissues and also in germ-free mice NLOs, albeit in lower numbers than in specific pathogen-free mice and following co-housing with 'pet-store' mice. They spatially co-localise with macrophages and regulate their polarization and function, promoting an anti-inflammatory phenotype, in-part via interleukin-10 production, with effects on bacterial clearance during urinary tract infection. Thus, our data reveal a critical role for tissue-resident B cells in determining the homeostatic 'inflammatory set-point' of myeloid cells, with important consequences for tissue immunity.
Supplementary Materials and Methods, Supplementary Table S1. Sources of cell lines and cell growth media; Supplemental Table S2. Sources of antibodies for flow cytometry; Supplementary Table S3. CS-1 ADC Characteristics, Supplemental Table S4. Pharmacokinetic profile of the CS-1 ADC; Supplemental Figure S1. Characterization of the CS-1 ADC molecule; Supplemental Figure S2. CS-1 ADC effect on tumor cell growth; Figure S3. Detailed results of colony forming assays; Supplementary Figure S4. CS-1 mAb and elotuzumab bind to similar cells in bone marrow.
The PKD1 gene, encoding protein polycystin-1 (PC1), is responsible for 85% of cases of autosomal dominant polycystic kidney disease (ADPKD). PC1 has been shown to be present in urinary exosome−like vesicles (PKD−ELVs) and lowered in individuals with germline PKD1 mutations. A label−free mass spectrometry comparison of urinary PKD−ELVs from normal individuals and those with PKD1 mutations showed that several proteins were reduced to a degree that matched the decrease observed in PC1 levels. Some of these proteins, such as polycystin-2 (PC2), may be present in a higher-order multi-protein assembly with PC1—the polycystin complex (PCC). CU062 (Q9NYP8) is decreased in ADPKD PKD−ELVs and, thus, is a candidate PCC component. CU062 is a small glycoprotein with a signal peptide but no transmembrane domain and can oligomerize with itself and interact with PC1. We investigated the localization of CU062 together with PC1 and PC2 using immunofluorescence (IF). In nonconfluent cells, all three proteins were localized in close proximity to focal adhesions (FAs), retraction fibers (RFs), and RF-associated extracellular vesicles (migrasomes). In confluent cells, primary cilia had PC1/PC2/CU062 + extracellular vesicles adherent to their plasma membrane. In cells exposed to mitochondrion-decoupling agents, we detected the development of novel PC1/CU062 + ring-like structures that entrained swollen mitochondria. In contact-inhibited cells under mitochondrial stress, PC1, PC2, and CU062 were observed on large, apically budding extracellular vesicles, where the proteins formed a reticular network on the membrane. CU062 interacts with PC1 and may have a role in the identification of senescent mitochondria and their extrusion in extracellular vesicles.
We and others have previously shown that the presence of renal innate immune cells can promote polycystic kidney disease (PKD) progression. In this study, we examined the influence of the inflammasome, a key part of the innate immune system, on PKD. The inflammasome is a system of molecular sensors, receptors, and scaffolds that responds to stimuli like cellular damage or microbes by activating Caspase-1, and generating critical mediators of the inflammatory milieu, including IL-1β and IL-18. We provide evidence that the inflammasome is primed in PKD, as multiple inflammasome sensors were upregulated in cystic kidneys from human ADPKD patients, as well as in kidneys from both orthologous (PKD1 RC/RC or RC/RC) and non-orthologous (jck) mouse models of PKD. Further, we demonstrate that the inflammasome is activated in female RC/RC mice kidneys, and this activation occurs in renal leukocytes, primarily in CD11c+ cells. Knock-out of Casp1, the gene encoding Caspase-1, in the RC/RC mice significantly restrained cystic disease progression in female mice, implying sex-specific differences in the renal immune environment. RNAseq analysis implicated the promotion of MYC/YAP pathways as a mechanism underlying the pro-cystic effects of the Caspase-1/inflammasome in females. Finally, treatment of RC/RC mice with hydroxychloroquine, a widely used immunomodulatory drug that has been shown to inhibit the inflammasome, protected renal function specifically in females and restrained cyst enlargement in both male and female RC/RC mice. Collectively, these results provide evidence for the first time that the activated Caspase-1/inflammasome promotes cyst expansion and disease progression in PKD, particularly in females. Moreover, the data suggest that this innate immune pathway may be a relevant target for therapy in PKD.
Macrophages are important drivers of pathogenesis and progression to AIDS in HIV infection. The virus in the later phases of the infection is often predominantly macrophage-tropic and this tropism contributes to a chronic inflammatory and immune activation state that is observed in HIV patients. Pattern recognition receptors of the innate immune system are the key molecules that recognise HIV and mount the inflammatory responses in macrophages. The innate immune response against HIV-1 is potent and elicits caspase-1-dependent pro-inflammatory cytokine production of IL-1β and IL-18. Although, NLRP3 has been reported as an inflammasome sensor dictating this response little is known about the pattern recognition receptors that trigger the "priming" signal for inflammasome activation, the NLRs involved or the HIV components that trigger the response. Using a combination of siRNA knockdowns in monocyte derived macrophages (MDMs) of different TLRs and NLRs as well as chemical inhibition, it was demonstrated that HIV Vpu could trigger inflammasome activation via TLR4/NLRP3 leading to IL-1β/IL-18 secretion. The priming signal is triggered via TLR4, whereas the activation signal is triggered by direct effects on Kv1.3 channels, causing K+ efflux. In contrast, HIV gp41 could trigger IL-18 production via NAIP/NLRC4, independently of priming, as a one-step inflammasome activation. NAIP binds directly to the cytoplasmic tail of HIV envelope protein gp41 and represents the first non-bacterial ligand for the NAIP/NLRC4 inflammasome. These divergent pathways represent novel targets to resolve specific inflammatory pathologies associated with HIV-1 infection in macrophages.
With Moore's law progressively running out of steam, heterogeneous computing architectures have been powering the top supercomputers in the world for many years and are now finding broader adoption across the industry. The trend towards sustainable computing also requires domain-specific heterogeneous hardware architectures, which promise further gains in energy efficiency. At the same time, today's high performance computing applications have evolved from monolithic simulations in a single domain to multidisciplinary complex workflows. In this paper, we explore how these trends affect system design decisions and what this means for future computing system architectures.
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