mRNA or ChAd0x1 COVID-19 Vaccination of Adolescents Induces Robust Antibody and Cellular Responses With Continued Recognition of Omicron Following mRNA-1273.

Children and adolescents generally experience mild COVID-19. However, those with underlying physical health conditions are at a significantly increased risk of severe disease. Here, we present a comprehensive analysis of antibody and cellular responses in adolescents with severe neuro-disabilities who received COVID-19 vaccination with either ChAdOx1 (n=6) or an mRNA vaccine (mRNA-1273, n=8, BNT162b2, n=1). Strong immune responses were observed after vaccination and antibody levels and neutralisation titres were both higher after two doses. Both measures were also higher after mRNA vaccination and were further enhanced by prior natural infection where one vaccine dose was sufficient to generate peak antibody response. Robust T-cell responses were generated after dual vaccination and were also higher following mRNA vaccination. Early T-cells were characterised by a dominant effector-memory CD4+ T-cell population with a type-1 cytokine signature with additional production of IL-10. Antibody levels were well-maintained for at least 3 months after vaccination and 3 of 4 donors showed measurable neutralisation titres against the Omicron variant. T-cell responses also remained robust, with generation of a central/stem cell memory pool and showed strong reactivity against Omicron spike. These data demonstrate that COVID-19 vaccines display strong immunogenicity in adolescents and that dual vaccination, or single vaccination following prior infection, generate higher immune responses than seen after natural infection and develop activity against Omicron. Initial evidence suggests that mRNA vaccination elicits stronger immune responses than adenoviral delivery, although the latter is also higher than seen in adult populations. COVID-19 vaccines are therefore highly immunogenic in high-risk adolescents and dual vaccination might be able to provide relative protection against the Omicron variant that is currently globally dominant.

Alteration of sensory neurons and spinal response to an experimental osteoarthritis pain model.

OBJECTIVE: To verify the biologic links between progressive cellular and structural alterations within knee joint components and development of symptomatic chronic pain that are characteristic of osteoarthritis (OA), and to investigate the molecular basis of alterations in nociceptive pathways caused by OA-induced pain. METHODS: An animal model of knee joint OA pain was generated by intraarticular injection of mono-iodoacetate (MIA) in Sprague-Dawley rats, and symptomatic pain behavior tests were performed. Relationships between development of OA with accompanying pain responses and gradual alterations in cellular and structural knee joint components (i.e., cartilage, synovium, meniscus, subchondral bone) were examined by histologic and immunohistologic analysis, microscopic examination, and microfocal computed tomography. Progressive changes in the dynamic interrelationships between peripheral knee joint tissue and central components of nociceptive pathways caused by OA-induced pain were examined by investigating cytokine production and expression in sensory neurons of the dorsal root ganglion and spinal cord. RESULTS: We observed that structural changes in components of the peripheral knee joint correlate with alterations in the central compartments (dorsal root ganglia and the spinal cord) and symptomatic pain assessed by behavioral hyperalgesia. Our comparative gene expression studies revealed that the pain pathways in MIA-induced knee OA may overlap, at least in part, with neuropathic pain mechanisms. Similar results were also observed upon destabilization of the knee joint in the anterior cruciate ligament transection and destabilization of the medial meniscus models of OA. CONCLUSION: Our results indicate that MIA-induced joint degeneration in rats generates an animal model that is suitable for mechanistic and pharmacologic studies on nociceptive pain pathways caused by OA, and provide key in vivo evidence that OA pain is caused by central sensitization through communication between peripheral OA nociceptors and the central sensory system. Furthermore, our data suggest a mechanistic overlap between OA-induced pain and neuropathic pain.

Basic fibroblast growth factor accelerates matrix degradation via a neuro-endocrine pathway in human adult articular chondrocytes.

Pain-related neuropeptides released from synovial fibroblasts, such as substance P, have been implicated in joint destruction. Substance P-induced inflammatory processes are mediated via signaling through a G-protein-coupled receptor, that is, neurokinin-1 tachykinin receptor (NK(1)-R). We determined the pathophysiological link between substance P and its receptor in human adult articular cartilage homeostasis. We further examined if catabolic growth factors such as basic fibroblast growth factor (bFGF or FGF-2) or IL-1beta accelerate matrix degradation via a neural pathway upregulation of substance P and NK(1)-R. We show here that substance P stimulates the production of cartilage-degrading enzymes, such as matrix metalloproteinase-13 (MMP-13), and suppresses proteoglycan deposition in human adult articular chondrocytes via NK(1)-R. Furthermore, we have demonstrated that substance P negates proteoglycan stimulation promoted by bone morphogenetic protein-7, suggesting the dual role of substance P as both a pro-catabolic and anti-anabolic mediator of cartilage homeostasis. We report that bFGF-mediated stimulation of substance P and its receptor NK(1)-R is, in part, through an IL-1beta-dependent pathway.

IFI16 in human prostate cancer.

Increased expression of IFI16 protein (encoded by the IFI16 gene) in normal human prostate epithelial cells is associated with cellular senescence-associated cell growth arrest. Consistent with a role for IFI16 protein in cellular senescence, the expression of IFI16 protein is either very low or not detectable in human prostate cancer cell lines. We now report that treatment of DU-145 and LNCaP prostate cancer cell lines with histone deacetylase inhibitor trichostatin A (TSA) or CGK1026 resulted in transcriptional activation of the IFI16 gene. The induction of IFI16 protein in LNCaP cells was dependent on the duration of TSA treatment. Furthermore, TSA treatment of LNCaP cells up-regulated the expression of Janus-activated kinase 1 protein kinase and modulated the transcription of certain IFN-activatable genes. However, overexpression of exogenous Janus-activated kinase 1 protein in LNCaP cells and treatment of cells with IFNs (alpha and gamma) did not increase the expression of IFI16. Instead, the transcriptional activation of IFI16 gene by TSA treatment of LNCaP cells was dependent on transcriptional activation by c-Jun/activator protein-1 transcription factor. Importantly, increased expression of IFI16 in LNCaP cells was associated with decreases in the expression of androgen receptor and apoptosis of cells. Conversely, knockdown of IFI16 expression in TSA-treated LNCaP cells increased androgen receptor protein levels with concomitant decreases in apoptosis. Together, our observations provide support for the idea that histone deacetylase-dependent transcriptional silencing of the IFI16 gene in prostate epithelial cells contributes to the development of prostate cancer.

Brain transit and ameliorative effects of intranasally delivered anti-amyloid-ß oligomer antibody in 5XFAD mice.

Alzheimer's disease (AD) is a global health crisis with limited treatment options. Despite major advances in neurotherapeutics, poor brain penetration due to the blood-brain barrier continues to pose a big challenge in overcoming the access of therapeutics to the central nervous system. In that regard, the non-invasive intranasal route of brain targeting is gaining considerable attention. The nasal mucosa offers a large surface area, rapid absorption, and avoidance of first-pass metabolism increasing drug bioavailability with less systemic side effects. Intranasal delivery is known to utilize olfactory, rostral migratory stream, and trigeminal routes to reach the brain. This investigation confirmed that intranasal delivery of oligomeric amyloid-ß antibody (NU4) utilized all three routes to enter the brain with a resident time of 96 hours post single bolus intranasal administration, and showed evidence of perikaryal and parenchymal uptake of NU4 in 5XFAD mouse brain, confirming the intranasal route as a non-invasive and efficient way of delivering therapeutics to the brain. In addition, this study demonstrated that intranasal delivery of NU4 antibody lowered cerebral amyloid-ß and improved spatial learning in 5XFAD mice.

Wheat germ agglutinin enhanced cerebral uptake of anti-Aß antibody after intranasal administration in 5XFAD mice.

Alzheimer's disease (AD) is the 6th leading cause of death in United States afflicting >5 million Americans. This number is estimated to triple by the middle of the century if effective treatments are not discovered. Current therapy for AD is mainly symptomatic. Effective disease-modifying treatments are needed that would eliminate the cause rather than the symptoms of the disease. Polymerization of monomeric beta-amyloid peptide (Aß) into dimers, soluble oligomers and insoluble fibrils is considered the prime causative factor in triggering AD pathogenesis. Based on these facts, removal/reduction of Aß has gained importance as a primary therapeutic target in treating the cause of the disease. In that regard, passive immunotherapy with direct delivery of anti-Aß antibodies to the brain has shown great promise, but awaits the challenge of overcoming greater influx of anti-Aß antibody into the brain. This investigation was undertaken to maximize direct delivery of immunotherapeutics to the brain by using wheat germ agglutinin (WGA) as a novel axonal transporter-carrier to be conjugated with anti-Aß antibody (6E10) raised against EFRHDS 3-8 amino acid (aa) epitopes of Aß known to react with 1-16 aa residues of mono-/di-/oligomeric Aß. This is the first report showing the use of WGA as an efficient axonal transporter carrier that not only enhanced the influx of anti-Aß antibody directly into the brain but also resulted in greater reduction of cerebral Aß compared to the unconjugated anti-Aß antibody delivered intranasally in Alzheimer's 5XFAD model.

Emerging roles of SUMO modification in arthritis.

Dynamic modification involving small ubiquitin-like modifier (SUMO) has emerged as a new mechanism of protein regulation in mammalian biology. Sumoylation is an ATP-dependent, reversible post-translational modification which occurs under both basal and stressful cellular conditions. Sumoylation profoundly influences protein functions and pertinent biological processes. For example, sumoylation modulates multiple components in the NFkappaB pathway and exerts an anti-inflammatory effect. Likewise, sumoylation of peroxisome proliferator-activated receptor gamma (PPARgamma) augments its anti-inflammatory activity. Current evidence suggests a role of sumoylation for resistance to apoptosis in synovial fibroblasts. Dynamic SUMO regulation controls the biological outcomes initiated by various growth factors involved in cartilage homeostasis, including basic fibroblast growth factors (bFGF or FGF-2), transforming growth factor-beta (TGF-beta) and insulin-like growth factor-1 (IGF-1). The impact of these growth factors on cartilage are through sumoylation-dependent control of the transcription factors (e.g., Smad, Elk-1, HIF-1) that are key regulators of matrix components (e.g., aggrecan, collagen) or cartilage-degrading enzymes (e.g., MMPs, aggrecanases). Thus, SUMO modification appears to profoundly affect chondrocyte and synovial fibroblast biology, including cell survival, inflammatory responses, matrix metabolism and hypoxic responses. More recently, evidence suggests that, in addition to their nuclear roles, the SUMO pathways play crucial roles in mitochondrial activity, cellular senescence, and autophagy. With an increasing number of reports linking SUMO to human diseases like arthritis, it is probable that novel and equally important functions of the sumoylation pathway will be elucidated in the near future.

Restoration of p53 expression in human cancer cell lines upregulates the expression of Notch1: implications for cancer cell fate determination after genotoxic stress.

Following genotoxic stress, transcriptional activation of target genes by p53 tumor suppressor is critical in cell fate determination. Here we report that the restoration of p53 function in human cancer cell lines that are deficient in p53 function upregulated the expression of Notch1. Interestingly, the expression of wild-type p53 in human prostate and breast cancer cell lines correlated well with increased expression of Notch1. Furthermore, knockdown of p53 expression in cancer cells that express wild-type p53 resulted in reduced expression of Notch1. Importantly, genotoxic stress to cancer cells that resulted in activation of p53 also upregulated the expression of Notch1. Moreover, p53-mediated induction of Notch1 expression was associated with stimulation of the activity of Notch-responsive reporters. Notably, p53 differentially regulated the expression of Notch family members: expression of Notch2 and Notch4 was not induced by p53. Significantly, treatment of cells with gamma secretase inhibitor, an inhibitor of Notch signaling, increased susceptibility to apoptosis in response to genotoxic stress. Together, our observations suggest that p53-mediated upregulation of Notch1 expression in human cancer cell lines contributes to cell fate determination after genotoxic stress.

Basic fibroblast growth factor stimulates matrix metalloproteinase-13 via the molecular cross-talk between the mitogen-activated protein kinases and protein kinase Cdelta pathways in human adult articular chondrocytes.

Excessive release of basic fibroblast growth factor (bFGF) during loading and/or injury of the cartilage matrix may contribute to the onset or progression of osteoarthritis. This pathological role may be related to the ability of bFGF to decrease proteoglycan synthesis and to antagonize the activity of anabolic growth factors in cartilage such as insulin-like growth factor-1 and bone morphogenetic protein 7 (BMP7 or OP-1). Matrix metalloproteinase-13 (MMP-13), a catabolic cartilage-degrading enzyme, is dramatically up-regulated by inflammatory cytokines or by fibronectin fragments in articular chondrocytes. In this study, we investigated MMP-13 production by bFGF using human articular chondrocytes. Endogenous concentration of bFGF in synovial fluids collected from arthritis patients and asymptomatic subjects showed a good linear correlation with the endogenous levels of MMP-13. bFGF stimulation of MMP-13 was mediated at the transcriptional level and, at least in part, by stimulation of interleukin-1 production. Also, our findings suggest that bFGF stimulation of MMP-13 required the activation of multiple MAPKs (ERK, p38, and JNK) by bFGF, and more importantly, bFGF activation of protein kinase C (PKC) delta played a key role in the MMP-13 stimulation. Indeed, PKCdelta is the only isoform associated with MMP-13 stimulation among the PKC isoforms tested. PKCdelta controls the bFGF response by regulating multiple MAPK pathways. Our results suggest that PKCdelta activation is a principal rate-limiting event in the bFGF-dependent stimulation of MMP-13 in human adult articular chondrocytes. We propose that deregulation of cross-talk between MAPK and PKCdelta signaling may contribute to the etiology of osteoarthritis in human patients.

Concurrent opposite effects of trichostatin A, an inhibitor of histone deacetylases, on expression of alpha-MHC and cardiac tubulins: implication for gain in cardiac muscle contractility.

Histone deacetylases (HDACs) are a family of enzymes that catalyze the removal of acetyl groups from core histones, resulting in change of chromatin structure and gene transcription activity. In the heart, HDACs are targets of hypertrophic signaling, and their nonspecific inhibition by trichostatin A (TSA) attenuates hypertrophy of cultured cardiac myocytes. In this study, we examined the effect of TSA on two major determinants of cardiac contractility: alpha-myosin heavy chain (MHC) expression and microtubular composition and organization. TSA upregulated the expression of alpha-MHC in cultured cardiac myocytes, as well as in an in vivo model of hypothyroid rats. Studies designed to delineate mechanisms of alpha-MHC induction by TSA revealed an obligatory role of early growth response factor-1 on activation of the alpha-MHC promoter. Concurrently, TSA downregulated the expression of alpha- and beta-tubulins and prevented the induction of tubulins by a hypertrophy agonist, ANG II. The ANG II-mediated increased proportion of alpha- and beta-tubulins associated with polymerized microtubules was also markedly reduced after treatment of cells by TSA. Results obtained from immunofluorescent microscopy indicated that TSA had no noticeable effect on the organization of cardiac microtubules in control cells, whereas it prevented the ANG II-induced dense parallel linear arrays of microtubules to a profile similar to that of controls. Together, these results demonstrate that inhibition of HDACs by TSA regulates the cardiac alpha-MHC and tubulins in a manner predictive of improved cardiac contractile function. These studies improve our understanding of the role of HDACs on cardiac hypertrophy with implications in development of new therapeutic agents for treatment of cardiac abnormalities.

Calcium/calmodulin-dependent protein kinase activates serum response factor transcription activity by its dissociation from histone deacetylase, HDAC4. Implications in cardiac muscle gene regulation during hypertrophy.

Serum response factor (SRF) plays a pivotal role in cardiac myocyte development, muscle gene transcription, and hypertrophy. Previously, elevation of intracellular levels of Ca2+ was shown to activate SRF function without involving the Ets family of tertiary complex factors through an unknown regulatory mechanism. Here, we tested the hypothesis that the chromatin remodeling enzymes of class II histone deacetylases (HDAC4) regulate SRF activity in a Ca2+-sensitive manner. Expression of HDAC4 profoundly repressed SRF-mediated transcription in both muscle and nonmuscle cells. Protein interaction studies demonstrated physical association of HDAC4 with SRF in living cells. The SRF/HDAC4 co-association was disrupted by treatment of cells with hypertrophic agonists such as angiotensin-II and a Ca2+ ionophore, ionomycin. Furthermore, activation of Ca2+/calmodulin-dependent protein kinase (CaMK)-IV prevented SRF/HDAC4 interaction and derepressed SRF-dependent transcription activity. The SRF.HDAC4 complex was localized to the cell nucleus, and the activated CaMK-IV disrupted HDAC4/SRF association, leading to export of HDAC4 from the nucleus and stimulation of SRF transcription activity. Thus, these results identify SRF as a functional interacting target of HDAC4 and define a novel tertiary complex factor-independent mechanism for SRF activation by Ca2+/CaMK-mediated signaling.

Increased expression of alternatively spliced dominant-negative isoform of SRF in human failing hearts.

Serum response factor (SRF) has been shown to play a key role in cardiac cell growth and muscle gene regulation. To understand the role of SRF in heart failure, we compared its expression pattern between control and failing human heart samples. Western blot analysis of control samples showed expression of four different isoforms of SRF, with ~67-kDa full-length SRF being the predominant isoform. Interestingly, in failing hearts we found robust expression of a low-molecular-mass (~52 kDa) SRF isoform, accompanied by decreased expression of full-length SRF. By RT-PCR and Southern blot analyses, we characterized this ~52-kDa SRF isoform as being encoded by an alternatively spliced form of SRF lacking exons 4 and 5 of the SRF primary RNA transcript (SRF-Delta4,5 isoform). We cloned SRF-Delta4,5 cDNA and showed that overexpression of this isoform into cells inhibits SRF-dependent activation of cardiac muscle genes. These results suggest that expression of SRF-Delta4,5 in failing hearts may in part contribute to impaired cardiac gene expression and consequently to the pathogenesis of heart failure.