👤 Joel M Garrett

We examined whether seven consecutive days of warm-water immersion could elevate resting and exercise-induced levels of brain-derived neurotrophic factor (BDNF), irisin and klotho in older adults. These biomarkers support cognitive and metabolic health, but their levels decline with age. Passive heat exposure, like warm-water immersion, may offer a promising alternative to exercise for enhancing cellular-level physiological resilience in populations where exercise is limited. Twelve habitually active older men (median [IQR] age: 68 [64-73] years; Show less

Genetic studies have established angiopoietin-related protein 4 (ANGPTL4) as a key regulator of triglyceride metabolism and a promising target to reduce atherosclerotic cardiovascular disease (ASCVD) risk beyond traditional risk factors. Human ANGPTL4 loss-of-function shows no adverse consequences and is associated with reduced triglycerides and remnant cholesterol, and a reduced risk of type 2 diabetes and ASCVD. Nonetheless, development of ANGPTL4 inhibitors has been delayed due to adverse findings in ANGPTL4-knockout mice fed a high saturated fat diet, including lipid accumulation in mesenteric lymph nodes, systemic inflammation, adverse clinical signs, and reduced survival. We previously reported the development and preclinical characterisation of MAR001, an ANGPTL4 inhibitory antibody. Here, we report a comprehensive safety assessment of ANGPTL4 inhibition, including novel analysis of genetic ANGPTL4 loss on mesenteric lymph node architecture in humans and two early-phase clinical trials. MAR001 was evaluated in a first-in-human, randomised, placebo-controlled, single-ascending-dose phase 1 study with three parts in which participants received a single subcutaneous injection of MAR001 or placebo. The study was developed and conducted by Novartis Biomedical Research (Cambridge, MA, USA). Eligible participants enrolled in part 1A were healthy men and women aged between 18 years and 65 years with a bodyweight of at least 50 kg and a BMI of 18-30 kg/m We found no evidence of clinical adversity in human germline ANGPTL4 loss-of-function, adding to preclinical support for initiating human studies. Between Nov 20, 2017, and Sept 10, 2019, in the first-in-human, randomised, placebo-controlled, single-ascending-dose phase 1 study, part 1A enrolled 32 healthy participants: six each received 15 mg, 50 mg, 150 mg, or 450 mg of MAR001, and eight received placebo. Part 1B enrolled 12 participants: nine received 450 mg of MAR001 and three received placebo. Part 1C enrolled 12 participants: eight received 450 mg of MAR001 and four received placebo. Between Nov 24, 2013, and July 1, 2024, in the multidose phase 1b/2a randomised, double-blind, placebo-controlled study, 55 participants were randomly assigned to receive subcutaneous injections of placebo (19 participants) or MAR001 at doses of 150 mg (ten participants), 300 mg (nine participants), or 450 mg (17 participants), followed by a 12-week safety follow-up period. MAR001 was safe and generally well tolerated, and we observed no treatment-related systemic inflammatory biomarker elevations or changes in mesenteric lymph node size or inflammation assessed by MRI. MAR001 (450 mg) yielded placebo-adjusted week 12 mean reductions in triglycerides of 52·7% (90% CI -77·0 to -28·3) and in remnant cholesterol of 52·5% (-76·1 to -28·9). ANGPTL4 inhibition with MAR001 can safely and effectively reduce circulating triglycerides and remnant cholesterol. The findings of these trials support further research and development of MAR001 as a promising potential lipid-lowering therapy to reduce risk of ASCVD. Marea Therapeutics. Show less

Osteoglophonic Dysplasia (OGD) is an autosomal dominant skeletal dysplasia characterized by impaired bone growth resulting in short stature, severe craniofacial abnormalities, and in some patients FGF23-mediated hypophosphatemia. It is caused by gain-of-function variants in FGFR1, particularly in or near the transmembrane domain of the receptor. We used CRISPR in mice to knock-in the FGFR1 p.N330I variant, chosen based on its association with FGF23 excess. Skeletal phenotyping of this Show less

Obesity is a major public health crisis associated with high mortality rates. Previous genome-wide association studies (GWAS) investigating body mass index (BMI) have largely relied on imputed data from European individuals. This study leveraged whole-genome sequencing (WGS) data from 88,873 participants from the Trans-Omics for Precision Medicine (TOPMed) Program, of which 51% were of non-European population groups. We discovered 18 BMI-associated signals (P < 5 × 10 Show less

Intestinal homeostasis is maintained by specialized host cells and the gut microbiota. Wnt/β-catenin signaling is essential for gastrointestinal development and homeostasis, and its dysregulation has been implicated in inflammation and colorectal cancer. Axin1 negatively regulates activated Wnt/β-catenin signaling, but little is known regarding its role in regulating host-microbial interactions in health and disease. Here, we aim to demonstrate that intestinal Axin1 determines gut homeostasis and host response to inflammation. Axin1 expression was analyzed in human inflammatory bowel disease datasets. To explore the effects and mechanism of intestinal Axin1 in regulating intestinal homeostasis and colitis, we generated new mouse models with Show less

Classically, Axin1 is considered a regulator of Wnt/β-catenin signaling. However, Axin1's roles in host-microbial interactions have been unknown. Our recent study has demonstrated that deletion of intestinal epithelial Axin1 in epithelial cells and Paneth cells protects the host against colitis by enhancing Show less

The establishment of a functional cerebral cortex depends on the proper execution of multiple developmental steps, culminating in dendritic and axonal outgrowth and the formation and maturation of synaptic connections. Dysregulation of these processes can result in improper neuronal connectivity, including that associated with various neurodevelopmental disorders. The γ-Protocadherins (γ-Pcdhs), a family of 22 distinct cell adhesion molecules that share a C-terminal cytoplasmic domain, are involved in multiple aspects of neurodevelopment including neuronal survival, dendrite arborization, and synapse development. The extent to which individual γ-Pcdh family members play unique versus common roles remains unclear. We demonstrated previously that the γ-Pcdh-C3 isoform (γC3), via its unique "variable" cytoplasmic domain (VCD), interacts in cultured cells with Axin1, a Wnt-pathway scaffold protein that regulates the differentiation and morphology of neurons. Here, we confirm that γC3 and Axin1 interact in the cortex Show less

Obesity is a major public health crisis associated with high mortality rates. Previous genome-wide association studies (GWAS) investigating body mass index (BMI) have largely relied on imputed data from European individuals. This study leveraged whole-genome sequencing (WGS) data from 88,873 participants from the Trans-Omics for Precision Medicine (TOPMed) Program, of which 51% were of non-European population groups. We discovered 18 BMI-associated signals ( Show less

Intestinal microbes and their metabolites affect the development of colorectal cancer (CRC). Short-chain fatty acids are metabolites generated by intestinal microbes from dietary fiber. We investigated the mechanisms by which free fatty acid receptor 2 (FFAR2), a receptor for short-chain fatty acids that can affect the composition of the intestinal microbiome, contributes to the pathogenesis of CRC. We performed studies with Apc Apc Loss of FFAR2 promotes colon tumorigenesis in mice by reducing gut barrier integrity, increasing tumor bacterial load, promoting exhaustion of CD8 Show less

Deregulation of the cyclin-dependent kinases (CDKs) has been implicated in the pathogenesis of multiple cancer types. Consequently, CDKs have garnered intense interest as therapeutic targets for the treatment of cancer. We describe herein the molecular and cellular effects of CCT068127, a novel inhibitor of CDK2 and CDK9. Optimized from the purine template of seliciclib, CCT068127 exhibits greater potency and selectivity against purified CDK2 and CDK9 and superior antiproliferative activity against human colon cancer and melanoma cell lines. X-ray crystallography studies reveal that hydrogen bonding with the DFG motif of CDK2 is the likely mechanism of greater enzymatic potency. Commensurate with inhibition of CDK activity, CCT068127 treatment results in decreased retinoblastoma protein (RB) phosphorylation, reduced phosphorylation of RNA polymerase II, and induction of cell cycle arrest and apoptosis. The transcriptional signature of CCT068127 shows greatest similarity to other small-molecule CDK and also HDAC inhibitors. CCT068127 caused a dramatic loss in expression of DUSP6 phosphatase, alongside elevated ERK phosphorylation and activation of MAPK pathway target genes. MCL1 protein levels are rapidly decreased by CCT068127 treatment and this associates with synergistic antiproliferative activity after combined treatment with CCT068127 and ABT263, a BCL2 family inhibitor. These findings support the rational combination of this series of CDK2/9 inhibitors and BCL2 family inhibitors for the treatment of human cancer. Show less

Major Depressive Disorder (MDD) is a common psychiatric disorder for which available medications are often not effective. The high prevalence of MDD and modest response to existing therapies compels efforts to better understand and treat the disorder. Decreased hippocampal volume with increasing duration of depression suggests altered gene expression or even a decrease in neurogenesis. Tissue punches from the dentate gyrus were collected postmortem from 23 subjects with MDD and 23 psychiatrically-normal control subjects. Total RNA was isolated and whole transcriptome paired-end RNA-sequencing was performed using an Illumina NextSeq 500. For each sample, raw RNA-seq reads were aligned to the Ensembl GRCh38 human reference genome. Analysis revealed 30 genes differentially expressed in MDD compared to controls (FDR<0.05). Down-regulated genes included several with inflammatory function (ISG15, IFI44L, IFI6, NR4A1/Nur-77) and GABBR1 while up-regulated genes included several with cytokine function (CCL2/MCP-1), inhibitors of angiogenesis (ADM, ADAMTS9), and the KANSL1 gene, a histone acetyltransferase. Similar analyses of specific subsets of MDD subjects (suicide vs. non-suicide, single vs. multiple episodes) yielded similar, though not identical, results. Enrichment analysis identified an over-representation of inflammatory and neurogenesis-related (ERK/MAPK) signaling pathways significantly altered in the hippocampal dentate gyrus in MDD. Together, these data implicate neuro-inflammation as playing a crucial role in MDD. These findings support continued efforts to identify adjunctive approaches towards the treatment of MDD with drugs including anti-inflammatory and neuroprotective properties. Show less

We have expressed and purified three soluble fragments of the human LRIG1-ECD (extracellular domain): the LRIG1-LRR (leucine-rich repeat) domain, the LRIG1-3Ig (immunoglobulin-like) domain, and the LRIG1-LRR-1Ig fragment using baculovirus vectors in insect cells. The two LRIG1 domains crystallised so that we have been able to determine the three-dimensional structures at 2.3Å resolution. We developed a three-dimensional structure for the LRIG1-ECD using homology modelling based on the LINGO-1 structure. The LRIG1-LRR domain and the LRIG1-LRR-1Ig fragment are monomers in solution, whereas the LRIG1-3Ig domain appears to be dimeric. We could not detect any binding of the LRIG1 domains or the LRIG1-LRR-1Ig fragment to the EGF receptor (EGFR), either in solution using biosensor analysis or when the EGFR was expressed on the cell surface. The FLAG-tagged LRIG1-LRR-1Ig fragment binds weakly to colon cancer cells regardless of the presence of EGFRs. Similarly, neither the soluble LRIG1-LRR nor the LRIG1-3Ig domains nor the full-length LRIG1 co-expressed in HEK293 cells inhibited ligand-stimulated activation of cell-surface EGFR. Show less

Cln3(Δex7/8) mice harbor the most common genetic defect causing juvenile neuronal ceroid lipofuscinosis (JNCL), an autosomal recessive disease involving seizures, visual, motor and cognitive decline, and premature death. Here, to more thoroughly investigate the manifestations of the common JNCL mutation, we performed a broad phenotyping study of Cln3(Δex7/8) mice. Homozygous Cln3(Δex7/8) mice, congenic on a C57BL/6N background, displayed subtle deficits in sensory and motor tasks at 10-14 weeks of age. Homozygous Cln3(Δex7/8) mice also displayed electroretinographic changes reflecting cone function deficits past 5 months of age and a progressive decline of retinal post-receptoral function. Metabolic analysis revealed increases in rectal body temperature and minimum oxygen consumption in 12-13 week old homozygous Cln3(Δex7/8) mice, which were also seen to a lesser extent in heterozygous Cln3(Δex7/8) mice. Heart weight was slightly increased at 20 weeks of age, but no significant differences were observed in cardiac function in young adults. In a comprehensive blood analysis at 15-16 weeks of age, serum ferritin concentrations, mean corpuscular volume of red blood cells (MCV), and reticulocyte counts were reproducibly increased in homozygous Cln3(Δ) (ex7/8) mice, and male homozygotes had a relative T-cell deficiency, suggesting alterations in hematopoiesis. Finally, consistent with findings in JNCL patients, vacuolated peripheral blood lymphocytes were observed in homozygous Cln3(Δ) (ex7/8) neonates, and to a greater extent in older animals. Early onset, severe vacuolation in clear cells of the epididymis of male homozygous Cln3(Δ) (ex7/8) mice was also observed. These data highlight additional organ systems in which to study CLN3 function, and early phenotypes have been established in homozygous Cln3(Δ) (ex7/8) mice that merit further study for JNCL biomarker development. Show less