👤 David Hunter

The progressive accumulation of physiological stress as we age, known as allostatic load, is linked to an increased risk of dementia. Fostering brain resilience through physical exercise can counteract allostatic load and improve adaptation to age-related brain alterations. Fibronectin type III domain-containing protein 5 (FNDC5)/irisin is a neuroprotective exercise-linked hormone found in extracellular vesicles (EV-FNDC5/irisin). Here, we sought to analyse EV-FNDC5/irisin in ageing as a promising biomarker of brain resilience. We measured exercise-associated factors, including EV-FNDC5/irisin, brain-derived neurotrophic factor (BDNF), and cathepsin B in the serum of 31 young (18-28 years) and 19 older subjects (65-79 years). Levels of FNDC5/irisin in serum-derived EVs are markedly reduced in older subjects compared to young ( Show less

Semaglutide (SEM) is a glucagon-like peptide-1 (GLP-1) receptor agonist formulated for oral delivery with the absorption enhancer salcaprozate sodium (SNAC). Although oral SEM achieves 0.4-1% bioavailability through gastric epithelial uptake, gastrointestinal (GI) adverse events remain a major cause of therapy discontinuation. This study examined the effects of SEM (0.74 mg/kg/day), SNAC (22 mg/kg/day), and combined SEM-SNAC (1:33 w/w) treatments on microbiota and metabolic function, in healthy Sprague Dawley rats over 21 days. Whilst microbial α-diversity remained stable, SNAC significantly altered β-diversity (PERMANOVA, p < 0.05) and depleted primary fermenters in Muribaculaceae (-62%) and Bacteroidaceae (-77%) compared to the control group. These compositional changes correlated with reduced predicted saccharolytic enzyme abundance and fecal butyrate concentrations (-77% SNAC, -75% SEM-SNAC). Plasma cytokine analysis showed elevated tumor necrosis factor-α (TNF-α, 70%) and suppressed brain-derived neurotrophic factor (BDNF, 85%), consistent with changes in circulating inflammatory and neurotrophic markers from SNAC monotherapy. SNAC-treated animals also exhibited increased liver weight and reduced caecum mass, occurring alongside microbiota compositional changes and altered fermentation-associated markers. Spearman correlations linked Muribaculaceae and Bacteroidaceae loss with decreased saccharolytic enzyme abundance, lower SCFA levels, and increased TNF-α. While these findings are associative and require mechanistic validation, they indicate that chronic SNAC exposure is linked to concurrent microbial, metabolic, and inflammatory marker changes in healthy rats, highlighting the potential need for alternative, microbiota-safe strategies for oral peptide delivery. Show less

To explore the associations between accelerometer-measured physical activity patterns and cardiovascular diseases (CVD), CVD-cause mortality, and all-cause mortality in people with osteoarthritis (OA). OA participants from the UK biobank with ≥36 h of accelerometer data, collected over one-week, were analyzed. Moderate to vigorous physical activity (MVPA) patterns were classified as: 'weekend warriors' (≥150 min/week, >50% on 1-2 days), active regular (>150 min/week), or inactive (<150 min/week). Mean min per week of light physical activity (LPA) were categorized into quartiles based on the distribution in the analytical sample. Among 10 210 study participants (mean age 58.1 ± 7.1 years; 64.5% female) followed for a median of 6.9 years, there were 1,538 incident cases of CVD, and 358 deaths, including 90 from CVD. Compared with inactive MVPA, both weekend warrior (adjusted hazard ratio, aHR (95% CIs); 0.73 (0.64-0.82)) and active regular MVPA (0.75 (0.65-0.87)) significantly lowered the risks of incident CVD. Notably, only the weekend warrior group showed significant reductions in CVD-cause mortality (0.55, 0.33-0.92), and all-cause mortality (0.75 (0.59-0.96)). Higher levels of LPA may link to lower CVD, CVD-cause mortality, and all-cause mortality risks in a dose-response manner. Subgroup analysis indicated that more prominent associations were found in individuals with a body mass index >30 or those aged over 60. Engaging in a weekend warrior pattern may confer unique survival benefits for OA patients, especially among older adults and those with obesity. LPA may have dose-dependent protective effects for CVD and mortality risk in OA patients. Show less

Dual glucagon-like peptide-1 receptor and glucose-dependent insulinotropic polypeptide receptor agonists (GLP1RA and GIPRA, respectively) synergise to reduce body weight. Though this synergy depends on receptors within the brain, where and how this occurs is unclear. We employed a combination of neuroanatomical approaches in the mouse to investigate access of the dual GLP1RA/GIPRA, tirzepatide, and study the central targets engaged by single agonist, dual agonist and combined agonist treatments. Genetic manipulations were then used to further investigate the functional significance of specific brain regions and distinct neuronal subtypes. We recorded penetration of fluorescently labelled tirzepatide limited mainly to circumventricular organs and confirmed the importance both GLP1R and GIPR in the dorsal vagal complex for the actions of systemically administered agonists. Receptor expression indicates GIPRA alone activates a distinct population of GABA neurons in the area postrema directly, but also neurotensin neurons in the central amygdala (Nts As with selective GLP1RA, the actions of dual GLP1RA/GIPA appear to be dependent on the dorsal vagal complex for their action, probably most importantly by gaining access through the area postrema. Downstream targets include the central amygdala where signals following dual receptor agonism interact. Specifically, Nts Show less

Disruption of photoreceptor-retinal pigment epithelium (RPE) interface with loss of photoreceptor outer segments (POSs) in the retina is a pathological hallmark of several neurodegenerative and retinal diseases including lysosomal storage disorder's like CLN3 disease. However, the retina is a functional composite Acid ceramidase deficiency and consequently altered sphingolipid signaling promotes disease phenotype(s) in a lysosomal storage disorder, CLN3 disease. Show less

CLN3 disease is a neuronopathic lysosomal storage disorder that severely impacts the central nervous system (CNS) while also inducing notable peripheral neuromuscular symptoms. Although considerable attention has been directed towards the neurodegenerative consequences within the CNS, the involvement of peripheral tissues, including skeletal muscles and their innervation, has been largely neglected. We hypothesized that, CLN3 deficiency could directly influence peripheral nerves and investigated the neuromuscular system in Cln3 Show less

Bone morphogenetic proteins (BMPs) and the fibroblast growth factor receptor 1 (FGFR1) gene play essential roles in the development and maintenance of the skeletal system. Brachydactyly is a genetic condition characterized by shortened or missing bones in the hands and feet. Several types of brachydactyly have been identified, each associated with different genetic mutations. However, some cases do not fit into existing classifications, necessitating further genetic investigation. A 34-year-old female patient with an absent middle phalanx in the second digit of her left foot and her 13-year-old son, who presented with absent or malformed middle and distal phalanx in all ten toes, are evaluated. Whole Genome Sequencing (WGS) analysis identifies a missense variant (c.1073A >T; p.K358M) in the BMP8A gene and a novel missense variant (c.1787C >T, p.Ser596Phe) in the FGFR1 gene. Functional protein association network analysis demonstrates a strong association of BMP8A and FGFR1 with other brachydactyly disease-causing genes. Given that these mutations have not been previously linked to any recognized brachydactyly subtype, they likely define a distinct genetic condition. The findings suggest a novel form of brachydactyly, which naming is proposed as brachydactyly type AB. Show less

Congenital viral infections can have severe consequences for pregnancy and fetal outcomes. Remarkably, the fetal-derived placenta serves as a robust barrier to infection through meticulous regulation by immune effectors and cytokines. Yet, the regulatory roles of many cytokines remain undefined at the maternal-fetal interface, including Interleukin-27 (IL-27). Here, we show that trophoblast organoids derived from human placentas constitutively express both IL-27 and its receptor, and restrict Zika virus infection through IL-27 signaling. Through bulk RNA-sequencing of trophoblast organoids in the absence and presence of IL-27 signaling, we demonstrate IL-27-mediated upregulation of antiviral genes. Finally, we show that IL-27 signaling is critical to restricting placental viral burdens and protecting against pathologic fetal outcomes during murine congenital Zika virus infection. In this work, we demonstrate a novel role for IL-27 in the placenta and establish IL-27 as an innate antiviral defense at the maternal-fetal interface during congenital viral infection. Show less

Many inflammatory stimuli can induce progenitor cells in the bone marrow to produce increased numbers of myeloid cells as part of the process of emergency myelopoiesis. These events are associated with trained immunity and have long-term impacts on hematopoietic stem and progenitor cell (HSPC) development but can also compromise their function. While many cytokines support emergency myelopoiesis, less is known about the mechanisms that temper these events. When mice that lack the cytokine IL-27 were infected with Show less

Regulatory T (Treg) cells express high levels of the IL-27R, and in the setting of infection and autoimmunity, the cytokine IL-27 promotes Treg cell activities that mitigate tissue pathology. However, IL-27 appears dispensable for Treg cell development and maintenance as lineage-specific depletion of the IL-27R on Treg cells does not impact these populations at steady state. In contrast, when mice were generated in which the Treg compartment comprised a mix of IL-27R-sufficient and -deficient Treg cells, those that lacked IL-27R were at a competitive disadvantage. Aging experiments illustrate that IL-27R-deficient Treg cells are preferentially eroded, and this defect was associated with reduced expression of CD122, the β chain of the IL-2/15R. Moreover, blockade of CD122 led to a similar loss of Treg cells, and in vitro and in vivo studies highlight that IL-27 promotes Treg cell expression of CD122 and improves responsiveness to IL-2/15. These datasets reveal that homeostatic IL-27 signals provide a competitive advantage that shapes the composition of the Treg cell pool by modulating responsiveness to growth factors. Show less

B cells express many protein ligands, yet their regulatory functions are incompletely understood. We profiled ligand expression across murine B sublineage cells, including those activated by defined receptor signals, and assessed their regulatory capacities and specificities through in silico analysis of ligand-receptor interactions. Consequently, we identified a B cell subset that expressed cytokine interleukin-27 (IL-27) and chemokine CXCL10. Through the IL-27-IL-27 receptor interaction, these IL-27/CXCL10-producing B cells targeted CD40-activated B cells in vitro and, upon induction by immunization and viral infection, optimized antibody responses and antiviral immunity in vivo. Also present in breast cancer tumors and retained there through CXCL10-CXCR3 interaction-mediated self-targeting, these cells promoted B cell PD-L1 expression and immune evasion. Mechanistically, Show less

Congenital viral infections can have severe consequences for pregnancy and fetal outcomes. Remarkably, the fetal-derived placenta serves as a robust barrier to infection through meticulous regulation by immune effectors and a diverse repertoire of cytokines. Yet, the regulatory roles of many cytokines remain undefined at the maternal-fetal interface. Interleukin 27 (IL-27) is a highly expressed cytokine in the placenta whose functional consequence during congenital infection is unknown. Here, we utilized trophoblast organoids (TO) derived from primary human placentas and a mouse model of congenital viral infection to uncover the functional role of IL-27 signaling during pregnancy. We show that TOs constitutively express IL-27 and its receptor, IL-27RA, and demonstrate that IL-27 signaling restricts Zika virus (ZIKV) infection of TOs. Through bulk RNA-sequencing of TOs in the absence and presence of IL-27 signaling, we demonstrate IL-27-mediated upregulation of antiviral genes. Finally, we show that IL-27 signaling is critical within the context of congenital murine ZIKV infection, as IL-27 restricts placental ZIKV burdens and protects against pathologic fetal outcomes early in gestation. These findings collectively demonstrate a novel role for IL-27 in the placenta and establish IL-27 as an innate antiviral defense at the maternal-fetal interface during congenital viral infection. Show less

Many inflammatory stimuli can induce progenitor cells in the bone marrow to produce increased numbers of myeloid cells as part of the process of emergency myelopoiesis. These events are associated with trained immunity and have long-term impacts on hematopoietic stem and progenitor cell (HSPC) development but can also compromise their function. While many cytokines support emergency myelopoiesis, less is known about the mechanisms that temper these events. When mice that lack the cytokine IL-27 were infected with Show less

Coronary artery disease (CAD) is the leading cause of death in India. Many genetic polymorphisms play a role in regulating oxidative stress, blood pressure and lipid metabolism, contributing to the pathophysiology of CAD. This study examined the association between ten polymorphisms and CAD in the Jat Sikh population from Northern India, also considering polygenic risk scores. This study included 177 CAD cases and 175 healthy controls. The genetic information of Show less

Waldenström's macroglobulinemia (WM) is defined as a lymphoplasmacytic lymphoma (LPL) with immunoglobulin M (IgM) monoclonal gammopathy and morphologic evidence of bone marrow infiltration by LPL. Immunophenotyping and genotyping provide a firm pathological basis for diagnosis and are particularly valuable in differential diagnosis between WM and related diseases. Emerging technologies in mutational analysis present new opportunities, but challenges remain around standardization of methodologies and reporting of mutational data across centers. The review provides an overview of the diagnosis of WM, with a particular focus on the role of immunophenotyping and genotyping. Demonstration of LPL with a bone marrow biopsy is essential to reach a definitive diagnosis of WM. However, Show less

Single cell-based analysis of macroautophagy/autophagy is largely achieved through the use of fluorescence microscopy to detect autophagy-related proteins that associate with autophagic membranes and therefore can be quantified as fluorescent puncta. In this context, an automated analysis of the number and size of recognized puncta is preferable to a manual count, because more reliable results can be generated in a short time. Here we present a method for open source CellProfiler software-based analysis for quantitative autophagy assessments using GFP-tagged WIPI1 (WD repeat domain, phosphoinositide interacting 1) images acquired with Airyscan or confocal laser-scanning microscopy. The CellProfiler protocol is provided as a ready-to-use software pipeline, and the creation of this pipeline is detailed in both text and video formats. In addition, we provide CellProfiler pipelines for endogenous SQSTM1/p62 (sequestosome 1) or intracellular lipid droplet (LD) analysis, suitable to assess forms of selective autophagy. All protocols and software pipelines can be quickly and easily adapted for the use of alternative autophagy markers or cell types, and can also be used for high-throughput purposes. Show less

Interleukin-27 (IL-27) uniquely assembles p28 and EBI3 subunits to a heterodimeric cytokine that signals via IL-27Rα and gp130. To provide the structural framework for receptor activation by IL-27 and its emerging therapeutic targeting, we report here crystal structures of mouse IL-27 in complex with IL-27Rα and of human IL-27 in complex with SRF388, a monoclonal antibody undergoing clinical trials with oncology indications. One face of the helical p28 subunit interacts with EBI3, while the opposite face nestles into the interdomain elbow of IL-27Rα to juxtapose IL-27Rα to EBI3. This orients IL-27Rα for paired signaling with gp130, which only uses its immunoglobulin domain to bind to IL-27. Such a signaling complex is distinct from those mediated by IL-12 and IL-23. The SRF388 binding epitope on IL-27 overlaps with the IL-27Rα interaction site explaining its potent antagonistic properties. Collectively, our findings will facilitate the mechanistic interrogation, engineering, and therapeutic targeting of IL-27. Show less

Autophagic pathways cross with lipid homeostasis and thus provide energy and essential building blocks that are indispensable for liver functions. Energy deficiencies are compensated by breaking down lipid droplets (LDs), intracellular organelles that store neutral lipids, in part by a selective type of autophagy, referred to as lipophagy. The process of lipophagy does not appear to be properly regulated in fatty liver diseases (FLDs), an important risk factor for the development of hepatocellular carcinomas (HCC). Here we provide an overview on our current knowledge of the biogenesis and functions of LDs, and the mechanisms underlying their lysosomal turnover by autophagic processes. This review also focuses on nonalcoholic steatohepatitis (NASH), a specific type of FLD characterized by steatosis, chronic inflammation and cell death. Particular attention is paid to the role of macroautophagy and macrolipophagy in relation to the parenchymal and non-parenchymal cells of the liver in NASH, as this disease has been associated with inappropriate lipophagy in various cell types of the liver. Show less

Craniofacial reconstruction of critical bone defects typically requires a bone graft. As graft availability may be restricted by disease or comorbidities, tissue engineering approaches are actively sought. The pericranium could provide new bone graft material. During development and repair, bone transitions through a chondrogenic phase. However, with tissue engineering, pluripotent cells can differentiate directly into bone cells. Does ability to recapitulate bone formation Show less

IL-27 controls a diverse range of immune responses in many disease settings. Here, we identify intestinal epithelial cells (IECs) as one of the major IL-27 cellular sources in the gut-associated tissue. Unlike IL-27 secreted by innate immune cells, gut epithelial IL-27 is dispensable for T-bet+ regulatory T cell (T reg cell) differentiation or IL-10 induction. Rather, IEC-derived IL-27 specifically promotes a distinct CD8αα+CD4+ intraepithelial lymphocyte (IEL) population that acquires their functional differentiation at the intestinal epithelium. Loss of IL-27 in IECs leads to a selective defect in CD8αα+CD4+ IELs over time. Consequently, mice with IEC-specific IL-27 ablation exhibited elevated pathogen burden during parasitic infection, and this could be rescued by transfer of exogenous CD8αα+CD4+ IELs. Collectively, our data reveal that in addition to its known regulatory properties in preventing immune hyperactivity, gut epithelial IL-27 confers barrier immunity by inducing a specific IEL subset and further suggest that IL-27 produced by different cell types plays distinct roles in maintaining intestinal homeostasis. Show less

The relationship between B cells and CD4 T cells has been carefully studied, revealing a collaborative effort in which B cells promote the activation, differentiation, and expansion of CD4 T cells while the so-called "helper" cells provide signals to B cells, influencing their class switching and fate. Interactions between B cells and CD8 T cells are not as well studied, although CD8 T cells exhibit an accelerated contraction after certain infections in B-cell-deficient mice. Here, we find that B cells significantly enhance primary CD8 T cell responses after vaccination. Moreover, memory CD8 numbers and function are impaired in B-cell-deficient animals, leading to increased susceptibility to bacterial challenge. We also show that interleukin-27 production by B cells contributes to their impact on primary, but not memory, CD8 responses. Better understanding of the interactions between CD8 T cells and B cells may aid in the design of more effective future vaccine strategies. Show less

Low-grade serous ovarian carcinoma (LGSOC) is associated with a poor response to existing chemotherapy, highlighting the need to perform comprehensive genomic analysis and identify new therapeutic vulnerabilities. The data presented here represent the largest genetic study of LGSOCs to date (n = 71), analysing 127 candidate genes derived from whole exome sequencing cohorts to generate mutation and copy-number variation data. Additionally, immunohistochemistry was performed on our LGSOC cohort assessing oestrogen receptor, progesterone receptor, TP53, and CDKN2A status. Targeted sequencing identified 47% of cases with mutations in key RAS/RAF pathway genes (KRAS, BRAF, and NRAS), as well as mutations in putative novel driver genes including USP9X (27%), MACF1 (11%), ARID1A (9%), NF2 (4%), DOT1L (6%), and ASH1L (4%). Immunohistochemistry evaluation revealed frequent oestrogen/progesterone receptor positivity (85%), along with CDKN2A protein loss (10%) and CDKN2A protein overexpression (6%), which were linked to shorter disease outcomes. Indeed, 90% of LGSOC samples harboured at least one potentially actionable alteration, which in 19/71 (27%) cases were predictive of clinical benefit from a standard treatment, either in another cancer's indication or in LGSOC specifically. In addition, we validated ubiquitin-specific protease 9X (USP9X), which is a chromosome X-linked substrate-specific deubiquitinase and tumour suppressor, as a relevant therapeutic target for LGSOC. Our comprehensive genomic study highlighted that there is an addiction to a limited number of unique 'driver' aberrations that could be translated into improved therapeutic paths. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Show less

Clinical and experimental studies have established that immune cells such as alternatively activated (M2) macrophages and Th17 cells play a role in the progression of chronic kidney disease, but the endogenous pathways that limit these processes are not well understood. The cytokine IL-27 has been shown to limit immune-mediated pathology in other systems by effects on these cell types, but this has not been thoroughly investigated in the kidney. Unilateral ureteral obstruction was performed on wild-type and IL-27Rα Show less

We report changes in the genomic landscape in the development of head and neck squamous cell carcinomas HNSCC from potentially premalignant lesions (PPOLS) to malignancy and lymph node metastases. Likely pathological mutations predominantly involved a relatively small set of genes reported previously (TP53, KMT2D, CDKN2A, PIK3CA, NOTCH1 and FAT1) but also other predicted cancer drivers (MGA, PABPC3, NR4A2, NCOR1 and MACF1). Notably, all these mutations arise early and are present in PPOLs. The most frequent genetic changes, which follow acquisition of immortality and loss of senescence, are of consistent somatic copy number alterations (SCNAs) involving chromosomal regions enriched for genes in known and previously unreported cancer-related pathways. We mapped the evolution of SCNAs in HNSCC progression. One of the earliest SCNAs involved deletions of CSMD1 (8p23.2). CSMD1 deletions or promoter hypermethylation were present in all of the immortal PPOLs and occurred at high frequency in the immortal HNSCC cell lines. Modulation of CSMD1 in cell lines revealed significant suppression of proliferation and invasion by forced expression, and significant stimulation of invasion by knockdown of expression. Known cancer drivers NOTCH1, PPP6C, RAC1, EIF4G1, PIK3CA showed significant increase in frequency of SCNA in transition from PPOLs to HNSCC that correlated with their expression. In the later stages of progression, HNSCC with and without nodal metastases showed some clear differences including high copy number gains of CCND1, hsa-miR-548k and TP63 in the metastases group. Show less

Peanut allergy (PA) is a complex disease with both environmental and genetic risk factors. Previously, PA loci were identified in filaggrin (FLG) and HLA in candidate gene studies, and loci in HLA were identified in a genome-wide association study and meta-analysis. We sought to investigate genetic susceptibility to PA. Eight hundred fifty cases and 926 hyper-control subjects and more than 7.8 million genotyped and imputed single nucleotide polymorphisms (SNPs) were analyzed in a genome-wide association study to identify susceptibility variants for PA in the Canadian population. A meta-analysis of 2 phenotypes (PA and food allergy) was conducted by using 7 studies from the Canadian, American (n = 2), Australian, German, and Dutch (n = 2) populations. An SNP near integrin α6 (ITGA6) reached genome-wide significance with PA (P = 1.80 × 10 This study identifies multiple novel loci as risk factors for PA and food allergy and establishes C11orf30 as a risk locus for both PA and food allergy. Multiple genes (C11orf30/EMSY, SKAP1, and CTNNA3) identified by this study are involved in epigenetic regulation of gene expression. Show less

Multi-subunit tethering complexes control membrane fusion events in eukaryotic cells. Class C core vacuole/endosome tethering (CORVET) and homotypic fusion and vacuole protein sorting (HOPS) are two such complexes, both containing the Sec1/Munc18 protein subunit VPS33A. Metazoans additionally possess VPS33B, which has considerable sequence similarity to VPS33A but does not integrate into CORVET or HOPS complexes and instead stably interacts with VIPAR. It has been recently suggested that VPS33B and VIPAR comprise two subunits of a novel multi-subunit tethering complex (named "CHEVI"), perhaps analogous in configuration to CORVET and HOPS. We utilized the BioID proximity biotinylation assay to compare and contrast the interactomes of VPS33A and VPS33B. Overall, few proteins were identified as associating with both VPS33A and VPS33B, suggesting that these proteins have distinct sub-cellular localizations. Consistent with previous reports, we observed that VPS33A was co-localized with many components of class III phosphatidylinositol 3-kinase (PI3KC3) complexes: PIK3C3, PIK3R4, NRBF2, UVRAG and RUBICON. Although VPS33A clearly co-localized with several subunits of CORVET and HOPS in this assay, no proteins with the canonical CORVET/HOPS domain architecture were found to co-localize with VPS33B. Instead, we identified that VPS33B interacts directly with CCDC22, a member of the CCC complex. CCDC22 does not co-fractionate with VPS33B and VIPAR in gel filtration of human cell lysates, suggesting that CCDC22 interacts transiently with VPS33B/VIPAR rather than forming a stable complex with these proteins in cells. We also observed that the protein complex containing VPS33B and VIPAR is considerably smaller than CORVET/HOPS, suggesting that the CHEVI complex comprises just VPS33B and VIPAR. Show less