From biochemical markers to molecular endotypes of osteoarthritis: a review on validated biomarkers

\ua9 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.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 effective patient care and successful drug development there is an urgent need to uncover the pathobiological drivers of OA and how these translate into disease endotypes. Endotypes provide a more precise and mechanistic definition of disease subgroups than observable phenotypes, and a panel of tissue- and pathology-specific biochemical markers may uncover treatable endotypes of OA. Areas covered: We have searched PubMed for full-text articles written in English to provide an in-depth narrative review of a panel of validated biochemical markers utilized for endotyping of OA and their association to key OA pathologies. Expert opinion: As utilized in IMI-APPROACH and validated in OAI-FNIH, a panel of biochemical markers may uncover disease subgroups and facilitate the enrichment of treatable molecular endotypes for recruitment in therapeutic clinical trials. Understanding the link between biochemical markers and patient-reported outcomes and treatable endotypes that may respond to given therapies will pave the way for new drug development in OA

Neurodevelopment and recovery from wasting

BACKGROUND AND OBJECTIVES Acute illness with malnutrition is a common indication for hospitalization among children in low- and middle-income countries. We investigated the association between wasting recovery trajectories and neurodevelopmental outcomes in young children 6 months after hospitalization for an acute illness. METHODS Children aged 2 to 23 months were enrolled in a prospective observational cohort of the Childhood Acute Illness & Nutrition Network, in Uganda, Malawi, and Pakistan between January 2017 and January 2019. We grouped children on the basis of their wasting recovery trajectories using change in mid–upper arm circumference for age z-score. Neurodevelopment was assessed with the Malawi Developmental Assessment Tool (MDAT development-for-age z-score [DAZ]) at hospital discharge and after 6 months. RESULTS We included 645 children at hospital discharge (mean age 12.3 months ± 5.5; 55% male); 262 (41%) with severe wasting, 134 (21%) with moderate wasting, and 249 (39%) without wasting. Four recovery trajectories were identified: high–stable, n = 112; wasted–improved, n = 404; severely wasted–greatly improved, n = 48; and severely wasted–not improved, n = 28. The children in the severely wasted–greatly improved group demonstrated a steep positive MDAT-DAZ recovery slope. This effect was most evident in children with both wasting and stunting (interaction wasted–improved × time × stunting: P < .001). After 6 months, the MDAT DAZ in children with wasting recovery did not differ from community children. In children who never recovered from wasting, there remained a significant delay in MDAT DAZ scores. CONCLUSIONS Neurodevelopment recovery occurred in parallel with wasting recovery in children convalescing from acute illness and was influenced by stunting

Bioenergetic profile of human coronary artery smooth muscle cells and effect of metabolic intervention

Bioenergetics of artery smooth muscle cells is critical in cardiovascular health and disease. An acute rise in metabolic demand causes vasodilation in systemic circulation while a chronic shift in bioenergetic profile may lead to vascular diseases. A decrease in intracellular ATP level may trigger physiological responses while dedifferentiation of contractile smooth muscle cells to a proliferative and migratory phenotype is often observed during pathological processes. Although it is now possible to dissect multiple building blocks of bioenergetic components quantitatively, detailed cellular bioenergetics of artery smooth muscle cells is still largely unknown. Thus, we profiled cellular bioenergetics of human coronary artery smooth muscle cells and effects of metabolic intervention. Mitochondria and glycolysis stress tests utilizing Seahorse technology revealed that mitochondrial oxidative phosphorylation accounted for 54.5% of ATP production at rest with the remaining 45.5% due to glycolysis. Stress tests also showed that oxidative phosphorylation and glycolysis can increase to a maximum of 3.5 fold and 1.25 fold, respectively, indicating that the former has a high reserve capacity. Analysis of bioenergetic profile indicated that aging cells have lower resting oxidative phosphorylation and reduced reserve capacity. Intracellular ATP level of a single cell was estimated to be over 1.1 mM. Application of metabolic modulators caused significant changes in mitochondria membrane potential, intracellular ATP level and ATP:ADP ratio. The detailed breakdown of cellular bioenergetics showed that proliferating human coronary artery smooth muscle cells rely more or less equally on oxidative phosphorylation and glycolysis at rest. These cells have high respiratory reserve capacity and low glycolysis reserve capacity. Metabolic intervention influences both intracellular ATP concentration and ATP:ADP ratio, where subtler changes may be detected by the latter

Viral entry and escape from antibody-mediated neutralization influence hepatitis C virus reinfection in liver transplantation

End-stage liver disease caused by chronic hepatitis C virus (HCV) infection is a leading cause for liver transplantation (LT). Due to viral evasion from host immune responses and the absence of preventive antiviral strategies, reinfection of the graft is universal. The mechanisms by which the virus evades host immunity to reinfect the liver graft are unknown. In a longitudinal analysis of six HCV-infected patients undergoing LT, we demonstrate that HCV variants reinfecting the liver graft were characterized by efficient entry and poor neutralization by antibodies present in pretransplant serum compared with variants not detected after transplantation. Monoclonal antibodies directed against HCV envelope glycoproteins or a cellular entry factor efficiently cross-neutralized infection of human hepatocytes by patient-derived viral isolates that were resistant to autologous host-neutralizing responses. These findings provide significant insights into the molecular mechanisms of viral evasion during HCV reinfection and suggest that viral entry is a viable target for prevention of HCV reinfection of the liver graft

Cytomegaloviral determinants of CD8+ T cell programming and RhCMV/SIV vaccine efficacy

Simian immunodeficiency virus (SIV) insert-expressing, 68–1 Rhesus Cytomegalovirus (RhCMV/SIV) vectors elicit major histocompatibility complex (MHC)-E- and -II-restricted, SIV-specific CD8(+) T cell responses, but the basis of these unconventional responses and their contribution to demonstrated vaccine efficacy against SIV challenge in the rhesus monkeys (RMs) has not been characterized. We show that these unconventional responses resulted from a chance genetic rearrangement in 68–1 RhCMV that abrogated the function of eight distinct immunomodulatory gene products encoded in two RhCMV genomic regions (Rh157.5/Rh157.4 and Rh158–161), revealing three patterns of unconventional response inhibition. Differential repair of these genes with either RhCMV-derived or orthologous human CMV (HCMV)-derived sequences (UL128/UL130; UL146/UL147) leads to either of two distinct CD8(+) T cell response types – MHC-Ia-restricted-only, or a mix of MHC-II- and MHC-Ia-restricted CD8(+) T cells. Response magnitude and functional differentiation are similar to RhCMV 68–1, but neither alternative response type mediated protection against SIV challenge. These findings implicate MHC-E-restricted CD8(+) T cell responses as mediators of anti-SIV efficacy and indicate that translation of RhCMV/SIV vector efficacy to humans will likely require deletion of all genes that inhibit these responses from the HCMV/HIV vector

Bleomycin and IL-1β–mediated pulmonary fibrosis is IL-17A dependent

Idiopathic pulmonary fibrosis (IPF) is a destructive inflammatory disease with limited therapeutic options. To better understand the inflammatory responses that precede and concur with collagen deposition, we used three models of pulmonary fibrosis and identify a critical mechanistic role for IL-17A. After exposure to bleomycin (BLM), but not Schistosoma mansoni eggs, IL-17A produced by CD4+ and γδ+ T cells induced significant neutrophilia and pulmonary fibrosis. Studies conducted with C57BL/6 il17a−/− mice confirmed an essential role for IL-17A. Mechanistically, using ifnγ−/−, il10−/−, il10−/−il12p40−/−, and il10−/−il17a−/− mice and TGF-β blockade, we demonstrate that IL-17A–driven fibrosis is suppressed by IL-10 and facilitated by IFN-γ and IL-12/23p40. BLM-induced IL-17A production was also TGF-β dependent, and recombinant IL-17A–mediated fibrosis required TGF-β, suggesting cooperative roles for IL-17A and TGF-β in the development of fibrosis. Finally, we show that fibrosis induced by IL-1β, which mimics BLM-induced fibrosis, is also highly dependent on IL-17A. IL-17A and IL-1β were also increased in the bronchoalveolar lavage fluid of patients with IPF. Together, these studies identify a critical role for IL-17A in fibrosis, illustrating the potential utility of targeting IL-17A in the treatment of drug and inflammation-induced fibrosis

Stable Cytotoxic T Cell Escape Mutation in Hepatitis C Virus Is Linked to Maintenance of Viral Fitness

Mechanisms by which hepatitis C virus (HCV) evades cellular immunity to establish persistence in chronically infected individuals are not clear. Mutations in human leukocyte antigen (HLA) class I-restricted epitopes targeted by CD8+ T cells are associated with persistence, but the extent to which these mutations affect viral fitness is not fully understood. Previous work showed that the HCV quasispecies in a persistently infected chimpanzee accumulated multiple mutations in numerous class I epitopes over a period of 7 years. During the acute phase of infection, one representative epitope in the C-terminal region of the NS3/4A helicase, NS31629-1637, displayed multiple serial amino acid substitutions in major histocompatibility complex (MHC) anchor and T cell receptor (TCR) contact residues. Only one of these amino acid substitutions at position 9 (P9) of the epitope was stable in the quasispecies. We therefore assessed the effect of each mutation observed during in vivo infection on viral fitness and T cell responses using an HCV subgenomic replicon system and a recently developed in vitro infectious virus cell culture model. Mutation of a position 7 (P7) TCR-contact residue, I1635T, expectedly ablated the T cell response without affecting viral RNA replication or virion production. In contrast, two mutations at the P9 MHC-anchor residue abrogated antigen-specific T cell responses, but additionally decreased viral RNA replication and virion production. The first escape mutation, L1637P, detected in vivo only transiently at 3 mo after infection, decreased viral production, and reverted to the parental sequence in vitro. The second P9 variant, L1637S, which was stable in vivo through 7 years of follow-up, evaded the antigen-specific T cell response and did not revert in vitro despite being less optimal in virion production compared to the parental virus. These studies suggest that HCV escape mutants emerging early in infection are not necessarily stable, but are eventually replaced with variants that achieve a balance between immune evasion and fitness for replication

Pathogenic effects of TIE2-mutations causing venous malformation

Venous malformations (VM) are localized defects of angiogenesis, which typically involve the skin, mucosa and subcutis. They are characterized by enlarged venous channels with a relative lack of surrounding smooth muscle cells (SMCs). While mostly sporadic (>98%), 1-2% occur as an autosomal dominantly inherited trait, named cutaneomucosal venous malformation (VMCM). Both forms can be caused by gain-of-function mutations in TEK, encoding the endothelial cell (EC) -specific tyrosine kinase receptor TIE2. Eight different inherited TIE2 changes have been implicated in VMCM, all of which induce a ligand-independent receptor hyperphosphorylation in vitro, from 2- to 30-fold that of the wild-type. The most common of these (10/17 families; 58.8%) is the mildly activating R849W (Publication I). A somatic second-hit was identified in tissue-derived cDNA from a patient carrying the R849W-mutation in the germline. It was located on the wild-type allele and partially deleted the ligand-binding domain of TIE2, resulting in a loss-of-function of the receptor (Publication II). At least 50% of common sporadic VMs are also caused by somatic activating mutations in TIE2. The mutations include a frequent L914F change (85.7%), and a series of double-mutations on the same allele (in cis). Like the inherited changes, all somatic TIE2 mutations cause hyperphosphorylation in vitro. L914F is phosphorylated 12-13 fold the level of wild-type TIE2, 4 times as strongly as R849W. Double-mutants cause higher (roughly additive) levels of chronic phosphorylation as compared to their constituent single-mutant forms. Interestingly, the most common TIE2 mutants (germline R849W and somatic L914F) have distinct but overlapping effects on receptor compartmentalization and translocation in response to angiopoietin-1 (ANGPT1) ligand (Publication II). Global gene expression profiling of human umbilical vein endothelial cells (HUVECs) overexpressing wild-type TIE2, the most frequent “weak” inherited mutant R849W, and the most frequent somatic mutant L914F revealed that L914F strongly dysregulates pathways involved in vascular development and cell migration. By contrast, R849W, in the absence of ligand-stimulation, has extremely weak effects, making it indistinguishable from wild-type cells in global analyses. In addition, we inferred that the transcription factor FOXO1 is inhibited in L914F mutant cells as compared to wild-type, based on differential expression of its target genes. Amongst these is the platelet derived growth factor beta (PDGFB), a known recruiter of SMCs, which shows a significant drop at the level of secreted protein from cultured cells, as well as ex vivo, around malformed veins as compared to normal veins or arteries. AKT, which has been shown to phosphorylate and therefore inhibit FOXO1, is highly activated by the TIE2 mutant forms. Inhibition of AKT increases PDGFB secretion in mutant cells, demonstrating an AKT/FOXO1-dependent role for TIE2 in the regulation of PDGFB production. This allowed us to hypothesize that TIE2 dysregulation causes smooth muscle cell paucity in VMs at least partially due to lack of PDGFB (Publication III, in preparation). In conclusion, the insights we have gained about the effects of TIE2 mutants allow us to explain some of the key features of the disease phenotype they mediate: lack of SMCs around lesions, lack of whose support may contribute to vessel dilation. In concert with in vivo mouse models of VMs currently being generated, these data will be of great value in deciphering why VMs occur, and which pathways are potentially attractive therapeutic targets. Les malformations veineuses (VM) sont des défauts localisés survenant lors de l'angiogenèse qui impliquent généralement la peau, les muqueuses et l'hypoderme. Elles sont caractérisées par des canaux veineux élargis avec un manque relatif de cellules musculaires lisses (SMC) les entourant. Alors que la plupart des malformations veineuses sont sporadiques (>98%), elles peuvent également se transmettre selon le mode autosomique dominant (1-2%). On parle alors de malformations veineuses mucocutanées (VMCM). Les deux formes sont causées par des mutations du gène TEK, codant un récepteur tyrosine kinase spécifique des cellules endothéliales (EC), TIE2. Toutes les mutations identifiées induisent un gain de fonction du récepteur. Huit changements héréditaires différents dans le gène TEK sont impliqués dans les VMCM. Ils induisent, in vitro, une hyperphosphorylation indépendante du ligand de 2 à 30 fois supérieure à celle du récepteur sauvage. Le changement le plus commun (10/17 familles; 58,8%) est la mutation légèrement autophosphorylante R849W (publication I). Un second-hit somatique a été identifié dans l’ADNc dérivé du tissu d'un patient porteur de la mutation germinale R849W. Il s’agit d’une délétion partielle de l'allèle sauvage entraînant la suppression d’une partie du domaine de liaison au ligand de TIE2. Ceci résulte en une perte de fonction du récepteur (publication II). Au moins 50% des malformations veineuses sporadiques sont également causées par des mutations somatiques activatrices dans TIE2. Les mutations comprennent le changement fréquent L914F (85,7%), et une série de doubles mutations situées sur le même allèle (en cis). Comme les changements héréditaires, toutes les mutations somatiques identifiées dans le gène TEK provoquent une hyperphosphorylation in vitro. Le niveau d’autophosphorylation de L914F est de 12 à 13 fois supérieur à celui du récepteur TIE2 sauvage et donc 4 fois plus élevé que celui de R849W. Les doubles mutations causent un niveau supérieur de phosphorylation (approximativement additif) par rapport à leurs constituants exprimés indépendamment. Fait intéressant, les mutations les plus communes de TIE2 (R849W germinale et L914F somatique) ont des effets distincts mais aussi communs sur la localisation intracellulaire et la translocation du récepteur en réponse au ligand Angpt1 (publication II). Des profils d'expressions géniques ont été réalisés sur 3 séries de cellules endothéliales provenant de la veine ombilicale humaine (HUVEC). Ces cellules étaient non infectées ou surexprimaient soit le récepteur TIE2 sauvage, le mutant le plus fréquemment identifié dans les cas familiaux R849W, ou le mutant le plus fréquemment identifié dans les cas somatiques L914F. Ces profils d’expressions géniques ont révélé que L914F modifie fortement les voies impliquées dans le développement vasculaire et la migration cellulaire, alors que R849W, en l'absence d’une stimulation par le ligand, a des effets extrêmement faibles. De plus, nous avons déduit que le facteur de transcription FOXO1 est inhibé dans les cellules mutantes L914F par rapport aux cellules exprimant le récepteur sauvage. Ce résultat est basé sur l'expression différentielle de ses gènes cibles. Parmi ces gènes cibles, le « Platelet Derived Growth Factor Beta » (PDGFB), un recruteur connu des cellules musculaires lisses, montre une baisse significative au niveau de la protéine sécrétée par les cellules en culture, ainsi que ex vivo, dans les veines malformés par rapport aux veines ou artères normales. AKT, qui a été montré comme phosphorylant et donc inhibant FOXO1, est fortement activé par les formes mutantes de TIE2. L'inhibition d'AKT augmente la sécrétion de PDGFB par les cellules mutantes, ce qui démontre le rôle de TIE2, dépendant de AKT/FOXO1, dans la régulation de la production de PDGFB. Ces résultats nous ont permis de montrer que le dérèglement de TIE2 entraîne une pénurie de cellules musculaires lisses dans les VM à cause du manque de PDGFB (Publication III, en préparation). En conclusion, les données que nous avons acquises sur les effets physiopathologiques des mutants TIE2 nous permettent d'expliquer une des caractéristiques principales de la maladie qu'ils entraînent: le manque de SMC autour des lésions contribuerait à la dilatation des vaisseaux. De concert avec des modèles de souris in vivo en cours de génération, ces données seront d'une grande valeur pour comprendre pourquoi les VM se produisent, et quelles sont les voies qui pourraient se révéler être des cibles thérapeutiques intéressantes.(SBIM 3) -- UCL, 201