Cytokine receptors: structures and signal transduction

Cell-free stem cell-derived extract formulation for treatment of knee osteoarthritis: study protocol for a preliminary non-randomized, open-label, multi-center feasibility and safety study

Background

Musculoskeletal conditions are highly prevalent, and knee OA is most common. Current treatment modalities have limitations and either fail to solve the underlying pathophysiology or are highly invasive. To address these limitations, attention has focused on the use of biologics. The efficacy of these devices is attributed to presence of growth factors (GFs), cytokines (CKs), and extracellular vesicles (EVs). With this in mind, we formulated a novel cell-free stem cell-derived extract (CCM) from human progenitor endothelial stem cells (hPESCs). A preliminary study demonstrated the presence of essential components of regenerative medicine, namely GFs, CKs, and EVs, including exosomes, in CCM. The proposed study aims to evaluate the safety and efficacy of intraarticular injection of the novel cell-free stem cell-derived extract (CCM) for the treatment of knee OA.

Methods and analysis

This is a non-randomized, open-label, multi-center, prospective study in which the safety and efficacy of intraarticular CCM in patients suffering from grade II/III knee OA will be evaluated. Up to 20 patients with grade II/III OA who meet the inclusion and exclusion criteria will be consented and screened to recruit 12 patients to receive treatment. The study will be conducted at up to 2 sites within the USA, and the 12 participants will be followed for 24 months. The study participants will be monitored for adverse reactions and assessed using Numeric Pain Rating Scale (NPRS), Patient-Reported Outcomes Measurement Information System (PROMIS) Score, Knee Injury and Osteoarthritis Outcome Score Jr. (KOOS Jr.), 36-ietm short form survey (SF-36), Single Assessment Numeric Evaluation (SANE), physical exams, plain radiography, and magnetic resonance imaging (MRI) with Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score for improvements in pain, function, satisfaction, and cartilage regeneration.

Discussion

This prospective study will provide valuable information into the safety and efficacy of intraarticular administration of cell-free stem cell-derived extract (CCM) in patients suffering with grade II/III knee OA. The outcomes from this initial study of novel CCM will lay the foundation for a larger randomized, placebo-controlled, multi-center clinical trial of intraarticular CCM for symptomatic knee OA.

Trial registration

Registered on July 21, 2021. ClinicalTrials.gov NCT04971798

Cell-free Stem Cell-Derived Extract Formulation for Regenerative Medicine Applications

Stem cells for regenerative medicine purposes offer therapeutic benefits, but disadvantages are still ill defined. The benefit of stem cells may be attributed to their secretion of growth factors (GFs), cytokines (CKs), and extracellular vesicles (EVs), including exosomes. We present a novel cell-free stem cell-derived extract (CCM), formulated from human progenitor endothelial stem cells (hPESCs), characterized for biologically active factors using ELISA, nanoparticle tracking analysis and single particle interferometric reflectance imaging sensing. The effect on fibroblast proliferation and ability to induce stem cell migration was analyzed using Alamar Blue proliferation and Transwell migration assays, respectively. GFs including IGFBP 1, 2, 3, and 6, insulin, growth hormone, PDGF-AA, TGF-α, TGF-β1, VEGF, and the anti-inflammatory cytokine, IL-1RA were detected. Membrane enclosed particles within exosome size range and expressing exosome tetraspanins CD81 and CD9 were identified. CCM significantly increased cell proliferation and induced stem cell migration. Analysis of CCM revealed presence of GFs, CKs, and EVs, including exosomes. The presence of multiple factors including exosomes within one formulation, the ability to promote cell proliferation and induce stem cell migration may reduce inflammation and pain, and augment tissue repair.

CytReD: A database collecting human cytokinome information

The cytokines/related receptors system represents a complex regulatory network that is involved in those chronic inflammatory processes which lead to many diseases as cancers. We developed a Cytokine Receptor Database (CytReD) to collect information on cytokine receptors related to their biological activity, gene data, protein structures and diseases in which these and their ligands are implicated. This large set of information may be used by researchers as well as by physicians or clinicians to identify which cytokines, reported in the literature, are important in a given disease and, therefore, useful for purposes of diagnosis or prognostic.

AVAILABILITY

The database is available for free at http://www.cro-m.eu/CytReD/

Serum Proteome of Leprosy Patients Undergoing Erythema Nodosum Leprosum Reaction: Regulation of Expression of the Isoforms of Haptoglobin

Validated proteome profile allows better understanding of disease progression, subtype classification, susceptibility patterns, and disease prognosis. Leprosy is a spectral disease, with clinically, histologically, immunologically, and bacteriologically distinguishable subtypes. In addition, a significant fraction of patients undergo immune mediated reactions even after multidrug therapy (MDT). Erythema nodosum leprosum (ENL) is an immune complex mediated reactional condition in leprosy, characterized by a systemic inflammatory condition afflicting borderline lepromatous (BL) and lepromatous leprosy patients (LL). In this study, we have analyzed serum proteome of leprosy patients undergoing ENL reactions and compared it with that of healthy noncontact controls. Depletion of albumin and immunoglobulin G (IgG) was optimized using Aurum serum protein mini kit (Bio-Rad), and then two-dimensional gel electrophoresis (2-DE) of these serum samples was performed. Differentially expressed proteins were identified by MALDI-TOF and MALDI-TOF MS/MS mass spectrometry. Significant increase in one of the isoforms of alpha2 chain of haptoglobin was observed in ENL condition. In addition, haptoglobin phenotype was determined for healthy controls and leprosy patients. Hp 0-0 phenotype was detected in 21.4% of the ENL patients undergoing treatment, which on follow up examination showed typable phenotype, thus showing a condition of acquired anhaptoglobinemia. Since ENL still remains a threat to leprosy disease management, the above findings may provide new insights in understanding the development and progression of this inflammatory condition.

RANK ligand and TNF-alpha mediate acid-induced bone calcium efflux in vitro

Chronic metabolic acidosis stimulates net calcium efflux from bone due to increased osteoclastic bone resorption and decreased osteoblastic collagen synthesis. Previously, we determined that incubation of neonatal mouse calvariae in medium simulating physiological metabolic acidosis leads to a significant, cyclooxygenase-dependent, increase in RNA for bone cell receptor activator of NF-kappaB ligand (RANKL) compared with incubation in neutral pH medium. In this study, we tested the hypothesis that the acid-mediated increase in RANKL expression is a primary mechanism for the stimulated osteoclastic resorption. Acid medium increased the medium concentration of sRANKL without altering the concentration of the decoy receptor osteoprotegerin (OPG). Inhibition of the RANKL pathway with concentrations of OPG up to 25 ng/ml, far greater than physiological, did not significantly decrease the robust acid-induced Ca efflux from bone nor did incubation of the calvariae with a different inhibitor, RANK/Fc (up to 50 ng/ml). Thus acid-induced net Ca efflux appears to involve mechanisms in addition to the RANK/RANKL pathway. Osteoblasts also produce TNF-alpha, another cytokine that stimulates the maturation and activity of osteoclasts. Incubation of calvariae in acid medium caused a significant increase in TNF-alpha levels. Incubation of calvariae with anti-TNF (up to 250 ng/ml) did not significantly decrease acid-induced net Ca efflux. However, the combination of RANK/Fc plus anti-TNF caused a significant but subtotal reduction in acid-induced Ca efflux, whereas the combination of RANK/Fc plus an isotype-matched control for the anti-TNF had no effect on Ca release. Thus simultaneous inhibition of RANKL and TNF-alpha is necessary to reduce acid-induced, cell-mediated net Ca efflux from bone; however, additional osteoblast-produced factors must also be involved in acid-induced, cell-mediated bone resorption.

Effect of targeted disruption of signal transducer and activator of transcription (Stat)4 and Stat6 genes on the autoimmune diabetes development induced by multiple low doses of streptozotocin

The MLDS (multiple low doses of streptozotocin) model of diabetes was induced in Stat4(-/-), Stat6(-/-), and double-deficient Stat4(-/-)/6(-/-) mice to examine the role of STAT4/STAT6 deficiency in development of autoimmune diabetes. Cytokine production of T-cells from Stat4(-/-) mice confirmed a predominantly Th2-type immune response. Stat4(-/-) mice exhibited delayed onset and reduced severity of disease compared to wild-type (WT) mice. In contrast, STAT6 deficiency, with a predominant Th1 response, did not influence the kinetics or severity of MLDS-induced autoimmune diabetes. Interestingly, Stat4(-/-)/6(-/-) mice, with a prominent Th1-type response, experienced an accelerated and aggravated course of diabetes after MLDS, implicating a STAT4-independent Th1 response in the immunopathogenesis of MLDS-induced autoimmune diabetes. The sensitivity of islet cells from Stat4(-/-) or Stat4(-/-)/6(-/-) mice to cytokines and STZ was not different from that of islet cells of WT mice. Hence, the observed effects of STAT4 and STAT4/6 deficiency on MLDS-induced autoimmune diabetes are likely due to their effects on T-cell responses.

Characterization of an antagonist interleukin-6 dimer by stable isotope labeling, cross-linking, and mass spectrometry

The homodimeric form of a recombinant cytokine interleukin-6 (IL-6(D)) is known to antagonize IL-6 signaling. In this study, spatially proximal residues between IL-6 chains in IL-6(D) were identified using a method for specific recognition of intermolecular cross-linked peptides. Our strategy involved mixing 1:1 (15)N-labeled and unlabeled ((14)N) protein to form a mixture of isotopically labeled and unlabeled homodimers, which was chemically cross-linked. This cross-linked IL-6(D) was subjected to proteolysis by trypsin and the generated peptides were analyzed by electrospray ionization time-of-flight mass spectrometry (MS). Molecular ions from cross-linked peptides of intermolecular origin are labeled with [(15)N/(15)N] + [(15)N/(14)N] + [(14)N/(15)N] + [(14)N/(14)N] yielding readily identified triplet/quadruplet MS peaks. All other peptide species are labeled with [(15)N] + [(14)N] yielding doublet peaks. Intermolecular cross-linked peptides were identified by MS, and cross-linked residues were identified. This intermolecular cross-link detection method, which we have designated "mixed isotope cross-linking" MIX may have more general application to protein-protein interaction studies. The pattern of proximal residues found was consistent with IL-6(D) having a domain-swapped fold similar to IL-10 and interferon-gamma. This fold implies that IL-6(D)-mediated antagonism of IL-6 signaling is caused by obstruction of cooperative gp130 binding on IL-6(D), rather than direct blocking of gp-130-binding sites on IL-6(D).

Effect of targeted disruption of STAT4 and STAT6 on the induction of experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is mediated by myelin-specific CD4(+) T cells secreting Th1 cytokines, while recovery from disease is associated with expression of Th2 cytokines. Investigations into the role of individual cytokines in disease induction have yielded contradictory results. Here we used animals with targeted deletion of the STAT4 or STAT6 genes to determine the role of these signaling molecules in EAE. The STAT4 pathway controls the differentiation of cells into a Th1 phenotype, while the STAT6 pathway controls the differentiation of cells into a Th2 phenotype. We found that mice deficient in STAT4 are resistant to the induction of EAE, with minimal inflammatory infiltrates in the central nervous system. In contrast, STAT6-deficient mice, which have a predominantly Th1 phenotype, experience a more severe clinical course of EAE as compared with wild-type or STAT4 knockout mice. In addition, adoptive transfer studies confirm the regulatory functions of a Th2 environment in vivo. These novel data indicate that STAT4 and STAT6 genes play a critical role in regulating the autoimmune response in EAE.

CD40 and LMP-1 both signal from lipid rafts but LMP-1 assembles a distinct, more efficient signaling complex

CD40, a member of the TNFR-1 receptor family, shares several features with LMP-1, an oncoprotein encoded by Epstein-Barr virus. CD40 and LMP-1 activate transcription by binding to TRAFs, JAK3 and/or TRADD. CD40's association with CD40L activates signaling. However, LMP-1 signals independently of a ligand but dependently on self-association. We demonstrate that activated CD40 and LMP-1 co-localize in lipid rafts and recruit TRAF3 there, findings consistent with signals of CD40 and LMP-1 being initiated from lipid rafts. To elucidate their signaling, we compared requirements for their aggregation and subcellular localization. Targeting CD40's monomeric C-terminal signaling domain to lipid rafts activates signaling, as does rendering it trimeric. Addition of both modifications supports signaling more efficiently. Parallel experiments with LMP-1 indicate that targeting the monomeric C-terminal signaling domain of LMP-1 to lipid rafts activates signaling, but trimerizing it does not. Fusing LMP-1's N-terminus and membrane-spanning domains to CD40's C-terminus supports signaling more efficiently than CD40 plus ligand or CD40's trimerized and/or localized derivatives. An activity of LMP-1's N-terminus and membrane-spanning domains other than trimerization must contribute to its efficient signaling.

Genomewide search in Canadian families with inflammatory bowel disease reveals two novel susceptibility loci

The chronic inflammatory bowel diseases (IBDs)-Crohn disease (CD) and ulcerative colitis (UC)-are idiopathic, inflammatory disorders of the gastrointestinal tract. These conditions have a peak incidence in early adulthood and a combined prevalence of approximately 100-200/100,000. Although the etiology of IBD is multifactorial, a significant genetic contribution to disease susceptibility is implied by epidemiological data revealing a sibling risk of approximately 35-fold for CD and approximately 15-fold for UC. To elucidate the genetic basis for these disorders, we undertook a genomewide scan in 158 Canadian sib-pair families and identified three regions of suggestive linkage (3p, 5q31-33, and 6p) and one region of significant linkage to 19p13 (LOD score 4.6). Higher-density mapping in the 5q31-q33 region revealed a locus of genomewide significance (LOD score 3.9) that contributes to CD susceptibility in families with early-onset disease. Both of these genomic regions contain numerous genes that are important to the immune and inflammatory systems and that provide good targets for future candidate-gene studies.

Cooperation between STAT5 and phosphatidylinositol 3-kinase in the IL-3-dependent survival of a bone marrow derived cell line

Cytokine-dependent activation of distinct signaling pathways is a common scheme thought to be required for the subsequent programmation into cell proliferation and survival. The PI 3-kinase/Akt, Ras/MAP kinase, Ras/NFIL3 and JAK/STAT pathways have been shown to participate in cytokine mediated suppression of apoptosis in various cell types. However the relative importance of these signaling pathways seems to depend on the cellular context. In several cases, individual inhibition of each pathway is not sufficient to completely abrogate cytokine mediated cell survival suggesting that cooperation between these pathways is required. Here we showed that individual inhibition of STAT5, PI 3-kinase or MEK activities did not or weakly affected the IL-3 dependent survival of the bone marrow derived Ba/F3 cell line. However, the simultaneous inhibition of STAT5 and PI 3-kinase activities but not that of STAT5 and MEK reduced the IL-3 dependent survival of Ba/F3. Analysis of the expression of the Bcl-2 members indicated that phosphorylation of Bad and Bcl-x expression which are respectively regulated by the PI 3-kinase/Akt pathway and STAT5 probably explain this cooperation. Furthermore, we showed by co-immunoprecipitation studies and pull down experiments with fusion proteins encoding the GST-SH2 domains of p85 that STAT5 in its phosphorylated form interacts with the p85 subunit of the PI 3-kinase. These results indicate that the activations of STAT5 and the PI 3-kinase by IL-3 in Ba/F3 cells are tightly connected and cooperate to mediate IL-3-dependent suppression of apoptosis by modulating Bad phosphorylation and Bcl-x expression.

Interleukins and tumor necrosis factor as inhibitors of food intake

Cytokines, such as interleukins and tumor necrosis factor-alpha (TNFalpha), are produced in response to immune stimulation and have systemic effects, mediated by the central nervous system (CNS). Interleukins, in particular interleukin [IL]-1beta, and TNFalpha reduce food intake after peripheral and central administration, suggesting that they contribute to the anorexia during various infectious, neoplastic and autoimmune diseases. Because cytokines are mainly produced in the periphery during most of these diseases, IL-1beta and TNFalpha may inhibit feeding indirectly through neural and humoral pathways activated by their peripheral actions. Activation of afferent nerve fibers by locally produced cytokines in the periphery is involved in several cytokine effects, but is not crucial for the anorectic effect of systemic immune stimulation. Cytokines increase OB protein (leptin) expression in the adipose tissue, and leptin may contribute to, but is also not essential for, the anorectic effects of cytokines. Finally, circulating IL-1beta and TNFalpha may act directly on the brain or cytokine synthesis in the brain may contribute to the anorectic effect of systemic immune stimulation. Central mediators of the anorectic effects of cytokines appear to be neurochemicals involved in the normal control of feeding, such as serotonin, corticotropin releasing factor, histamine, alpha-melanocyte stimulating hormone, and neuropeptide Y. The well-documented cytokine production in the gut in relation to feeding and the expression of TNFalpha by adipocytes suggest that IL-1beta and TNFalpha may also play a role in the control of normal feeding and energy balance. All in all, reciprocal, synergistic and antagonistic interactions between various pleiotropic cytokines and between cytokines and neurochemicals form a complex network that mediates the effects of cytokines on feeding and energy balance.