Jonathan Larkin

SynOA Therapeutics

Extracellular matrix remodeling mechanisms are understudied in cardiac development and congenital heart defects. We show that matrix-degrading metalloproteases ADAMTS1 and ADAMTS5, are extensively co-expressed during mouse cardiac development. The mouse mutants of each gene have mild cardiac anomalies, however, their combined genetic inactivation t...

Introduction: Osteoarthritis (OA) affects over 500 million people worldwide. OA patients are symptomatically treated, and current therapies exhibit marginal efficacy and frequently carry safety-risks associated with chronic use. No disease-modifying therapies have been approved to date leaving surgical joint replacement as a last resort. To enable...

Objectives: To efficiently assess the disease-modifying potential of new osteoarthritis treatments, clinical trials need progression-enriched patient populations. To assess whether the application of machine learning results in patient selection enrichment, we developed a machine learning recruitment strategy targeting progressive patients and val...

Osteoarthritis (OA) is the most common form of arthritis and a major source of pain and disability in the adult population. There is a significant unmet medical need for the development of effective pharmacological therapies for the treatment of OA. In addition to spontaneously occurring animal models of OA, many experimental animal models have bee...

Background The characterization of differential molecular endotypes in osteoarthritis (OA) is essential for enabling patient stratification to enhance clinical trials, facilitate the development of targeted and individualized treatments. Objectives This study aimed to characterize the profile and dynamics over 24 months (24M) of proteins present i...

Objectives The IMI-APPROACH knee osteoarthritis study used machine learning (ML) to predict structural and/or pain progression, expressed by a structural (S) and pain (P) predicted-progression score, to select patients from existing cohorts. This study evaluates the actual 2-year progression within IMI-APPROACH, in relation to the predicted progres...

Objective To investigate the association of the lipidomic profile with osteoarthritis (OA) severity, considering the outcomes radiographic knee and hand OA, pain and function. Design We used baseline data from the APPROACH cohort, comprising persons with knee OA fulfilling the clinical American College of Rheumatology classification criteria. Radi...

Objectives Osteoarthritis (OA) patient stratification is an important challenge to design tailored treatments and drive drug development. Biochemical markers reflecting joint tissue turnover were measured in the IMI-APPROACH cohort at baseline and analysed using a machine learning approach in order to study OA-dominant phenotypes driven by the endo...

APPROACH is an EU-wide research consortium with the goal to identify different subgroups of knee osteoarthritis to enable future differential diagnosis and treatment. During a 2-year clinical study images, biomarkers and clinical data are collected from people living with knee osteoarthritis and data are analyzed to confirm patterns that can indica...

Objectives Osteoarthritis (OA) patients with a neuropathic pain (NP) component may represent a specific phenotype. This study compares joint damage, pain and functional disability between knee OA patients with a likely NP component, and those without a likely NP component. Methods Baseline data from the Innovative Medicines Initiative Applied Publ...

Objective Cartilage degradation is a hallmark of osteoarthritis (OA). Aggrecan, a major proteoglycan of articular cartilage extracellular matrix (ECM), is degraded by ADAMTS-5 resulting in the release of ARGS-G2 fragments to synovial fluid and circulation. The aim was to quantify ARGS-G2 in the serum of OA patients using the huARGS immunoassay. Me...

Purpose The Applied Public-Private Research enabling OsteoArthritis Clinical Headway (APPROACH) consortium intends to prospectively describe in detail, preselected patients with knee osteoarthritis (OA), using conventional and novel clinical, imaging, and biochemical markers, to support OA drug development. Participants APPROACH is a prospective c...

Conventional inclusion criteria used in osteoarthritis clinical trials are not very effective in selecting patients who would benefit from a therapy being tested. Typically majority of selected patients show no or limited disease progression during a trial period. As a consequence, the effect of the tested treatment cannot be observed, and the effo...

Conventional inclusion criteria used in osteoarthritis clinical trials are not very effective in selecting patients who would benefit the most from a therapy under test. Typically these criteria select majority of patients who show no or limited disease progression during a short evaluation window of the study. As a consequence, less insight on the...

Background Disease modifying therapy of osteoarthritis (OA) represents an unmet clinical need, and appropriate outcome measures are required that can robustly identify patients with different OA phenotypes who may benefit from specific and more targeted therapies. APPROACH is an exploratory, 5-centre, 2-year prospective follow-up European cohort st...

A novel method for crystallization utilizing solvent/antisolvent extraction in microfluidic droplet liquid reactors has been developed. The method involves a ternary solvent system consisting of a dispersed phase of two miscible fluids, one in which the Active Pharmaceutical Ingredient (API) is soluble (solvent) and one in which the API is insolubl...

Purpose of review: This review focuses on the molecular taxonomy of osteoarthritis from the perspective of molecular biomarkers. We discuss how wet biochemical markers may be used to understand disease pathogenesis and progression and define molecular endotypes of osteoarthritis and how these correspond to clinical phenotypes. Recent findings: E...

Purpose: The aim of this "Year in Review" article is to summarize and discuss the implications of biochemical marker related articles published between the Osteoarthritis Research Society International (OARSI) 2015 Congress in Seattle and the OARSI 2016 Congress in Amsterdam. Methods: The PubMed/MEDLINE bibliographic database was searched using...

Objective: The primary goal of this study was to test the disease-modifying effect of blocking a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-5 with a neutralizing monoclonal antibody (mAb) starting 4 weeks after destabilization of the medial meniscus (DMM) in the mouse. We also investigated whether ADAMTS-5 blockade rever...

Aggrecanase activity, most notably ADAMTS-5, is implicated in pathogenic cartilage degradation. Selective monoclonal antibodies (mAbs) to both ADAMTS-5 and ADAMTS-4 were generated and in vitro, ex vivo and in vivo systems were utilized to assess target engagement, aggrecanase inhibition and modulation of disease-related endpoints with the intent of...

Proteolysis of the Glu441-Ala442 bond in the glycosaminoglycan (GAG) β domain of the versican-V1 variant by a disintegrin-like and metalloproteinase domain with thrombospondin type 1 motif (ADAMTS) proteases is required for proper embryo morphogenesis. However, the processing mechanism and the possibility of additional ADAMTS-cleaved processing sit...

Osteoarthritis Cartilage

To characterise ARGS neoepitope concentrations in various matrices from patients with knee osteoarthritis (OA) and assess performance of an immunoassay to facilitate clinical development of therapeutics affecting the ADAMTS-5 pathway. Matched sera, urine, and synovial fluid (surgical subjects only) were collected from healthy subjects, subjects wit...

Pulmonary edema resulting from high pulmonary venous pressure (PVP) is a major cause of morbidity and mortality in heart failure (HF) patients, but current treatment options demonstrate substantial limitations. Recent evidence from rodent lungs suggests that PVP-induced edema is driven by activation of pulmonary capillary endothelial transient rece...

The metalloprotease ADAMTS-5 is considered a potential target for the treatment of osteoarthritis. To identify selective inhibitors of ADAMTS-5, we employed encoded library technology (ELT), which enables affinity selection of small molecule binders from complex mixtures by DNA tagging. Selection of ADAMTS-5 against a four-billion member ELT librar...

Hepatitis C virus (HCV)-specific impairments in host immunity have been described at multiple levels of the innate and adaptive response, which may lead to viral persistence in the majority of infections. Understanding of HCV-associated immune defects could lead to novel therapeutic advances. Natural killer (NK) cells, the major effector cells of t...

NK T (NKT) cells are an important component of the innate immune system and recognize the MHC class I-like CD1d molecule. NKT cells possess significant immunoregulatory activity due to their rapid secretion of large quantities of pro- and anti-inflammatory cytokines following CD1d-dependent stimulation. Because the innate immune system is programme...

The development of fibrosis and cirrhosis during chronic hepatitis B virus (HBV) infection correlates with the persistent expression of HBV x antigen (HBxAg), which acts in part, by stimulating selected signal transduction pathways, including nuclear factor kappa B (NF-kappa B). To identify NF-kappa B responsive genes that are differentially expres...

With the advent of blood tests capable of identifying hepatitis B virus (HBV), and the development of an effective vaccine (1), one of the major challenges that remains is what to do with people who are chronic carriers of HBV. This is important because there are an estimated 350 million chronic carriers of HBV worldwide (2) who are at high risk fo...

The use of type I interferon (IFN), in combination with ribvirin, to treat chronic hepatitis C virus (HCV) infection has many drawbacks that prevent widespread application, ultimately leading to a significant unmet clinical need. Potential improvements in IFN therapy through targeted delivery, molecular alteration, and combination with other agents...

Epidemiologic observations show a higher frequency of hepatitis B virus (HBV) serologic markers in chronic alcoholics compared with the general population. This may be the result of an increased susceptibility of alcoholics to infection and/or to an ethanol-mediated stimulation of HBV gene expression and replication. To test the latter hypothesis,...

The narrow host range of infection and lack of suitable tissue culture systems for the propagation of hepatitis B and C viruses are limitations that have prevented a more thorough understanding of persistent infection and the pathogenesis of chronic liver disease. With hepatitis B virus (HBV), this lack of knowledge has been partially overcome by t...

A model for hepatitis B virus-associated chronic liver disease has been made using cloned hepatitis B virus DNA as a transgene in a severe combined immunodeficient host. These mice consistently support virus gene expression and replication. After adoptive transfer of unprimed, syngeneic splenocytes, these mice cleared virus from liver and serum, an...

The key signal transduction enzyme protein kinase C (PKC) contains a hydrophobic binding site for alcohols and anesthetics (Slater, S. J., Cox, K. J. A., Lombardi, J. V., Ho, C., Kelly, M. B., Rubin, E., and Stubbs, C. D. (1993) Nature 364, 82-84). In this study, we show that interaction of n-alkanols and general anesthetics with PKCα results in dr...

The key signal transduction enzyme protein kinase C (PKC) contains a hydrophobic binding site for alcohols and anesthetics (Slater, S. J., Cox, K. J. A., Lombardi, J. V., Ho, C., Kelly, M. B., Rubin, E., and Stubbs, C. D. (1993) Nature 364, 82-84). In this study, we show that interaction of n-alkanols and general anesthetics with PKCα results in dr...

Based on marked differences in the enzymatic properties of diacylglycerols compared with phorbol ester-activated protein kinase C (PKC), we recently proposed that activation induced by these compounds may not be equivalent (Slater, S. J., Kelly, M. B., Taddeo, F. J., Rubin, E., and Stubbs, C. D. (1994) J. Biol. Chem. 269, 17160-17165). In the prese...

The effect of variation of the degree ofcis-unsaturation on cell membrane protein functioning was investigated using a model lipid bilayer system and protein kinase C (PKC). This protein is a key element of signal transduction. Furthermore it is representative of a class of extrinsic membrane proteins that show lipid dependent interactions with cel...

The rat Via vasopressin receptor (VlaR) has been expressed in Sf9 insect cells after infection with recombinant baculovirus. The receptor was functionally expressed in the plasma membrane as shown by arginine vasopressin elicited Ca transients that utilize the endogenous Sf9 G-protein/phospholipase C system Ca2' levels were measured using digital i...

Based on marked differences in the enzymatic properties of diacylglycerols compared to phorbol ester-activated protein kinase C (PKC), we recently proposed that activation induced by these compounds may not be equivalent (Slater et al.,y. Biol. Chem. 269, 17160, 1994) Using a novel binding assay employing the fluorescent phorbol ester, sapintoxin-D...

The key metabolite of vitamin D3, 1 alpha,25-dihydroxyvitamin D3 (1,25-D3), induces rapid cellular responses that constitute a so-called "non-genomic" response. This effect is distinguished from its "classic" genomic role in calcium homeostasis involving the nuclear 1,25-D3 receptor. Evidence is presented that protein kinase C (PKC) is directly act...