Pharmacodynamic evaluation and safety assessment of treatment with antibodies to serum amyloid P component in patients with cardiac amyloidosis: an open-label Phase 2 study and an adjunctive immuno-PET imaging study.

BACKGROUND: In a Phase I study treatment with the serum amyloid P component (SAP) depleter miridesap followed by monoclonal antibody to SAP (dezamizumab) showed removal of amyloid from liver, spleen and kidney in patients with systemic amyloidosis. We report results from a Phase 2 study and concurrent immuno-positron emission tomography (PET) study assessing efficacy, pharmacodynamics, pharmacokinetics, safety and cardiac uptake (of dezamizumab) following the same intervention in patients with cardiac amyloidosis. METHODS: Both were uncontrolled open-label studies. After SAP depletion with miridesap, patients received ≤ 6 monthly doses of dezamizumab in the Phase 2 trial (n = 7), ≤ 2 doses of non-radiolabelled dezamizumab plus [89Zr]Zr-dezamizumab (total mass dose of 80 mg at session 1 and 500 mg at session 2) in the immuno-PET study (n = 2). Primary endpoints of the Phase 2 study were changed from baseline to follow-up (at 8 weeks) in left ventricular mass (LVM) by cardiac magnetic resonance imaging and safety. Primary endpoint of the immuno-PET study was [89Zr]Zr-dezamizumab cardiac uptake assessed via PET. RESULTS: Dezamizumab produced no appreciable or consistent reduction in LVM nor improvement in cardiac function in the Phase 2 study. In the immuno-PET study, measurable cardiac uptake of [89Zr]Zr-dezamizumab, although seen in both patients, was moderate to low. Uptake was notably lower in the patient with higher LVM. Treatment-associated rash with cutaneous small-vessel vasculitis was observed in both studies. Abdominal large-vessel vasculitis after initial dezamizumab dosing (300 mg) occurred in the first patient with immunoglobulin light chain amyloidosis enrolled in the Phase 2 study. Symptom resolution was nearly complete within 24 h of intravenous methylprednisolone and dezamizumab discontinuation; abdominal computed tomography imaging showed vasculitis resolution by 8 weeks. CONCLUSIONS: Unlike previous observations of visceral amyloid reduction, there was no appreciable evidence of amyloid removal in patients with cardiac amyloidosis in this Phase 2 trial, potentially related to limited cardiac uptake of dezamizumab as demonstrated in the immuno-PET study. The benefit-risk assessment for dezamizumab in cardiac amyloidosis was considered unfavourable after the incidence of large-vessel vasculitis and development for this indication was terminated. Trial registration NCT03044353 (2 February 2017) and NCT03417830 (25 January 2018).

Evolution and treatment of idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic and devastating disease of unknown etiology, characterized by irreversible morphological changes, ultimately leading to lung fibrosis and death. In recent years, significant progress has been achieved in understanding the pathogenesis of IPF. Moreover, we assisted to the conceptual change of the pathogenic hypothesis that currently considers IPF as a primarily fibrotic driven disease. However, despite the undeniable progress, the diagnosis of IPF remains still very complex requiring the presence of a team of experts to achieve the highest level of diagnostic confidence. The advent of antifibrotics has radically changed the treatment landscape of IPF and new promising drugs are currently under evaluation. Furthermore, a more extensive use of non-pharmacological treatments has also to be encouraged in all patients both to reduce symptoms and improve quality of life.

Serum Amyloid P Component (SAP) Interactome in Human Plasma Containing Physiological Calcium Levels.

The pentraxin serum amyloid P component (SAP) is secreted by the liver and found in plasma at a concentration of approximately 30 mg/L. SAP is a 25 kDa homopentamer known to bind both protein and nonprotein ligands, all in a calcium-dependent manner. The function of SAP is unclear but likely involves the humoral innate immune system spanning the complement system, inflammation, and coagulation. Also, SAP is known to bind to the generic structure of amyloid deposits and possibly to protect them against proteolysis. In this study, we have characterized the SAP interactome in human plasma containing the physiological Ca2+ concentration using SAP affinity pull-down and co-immunoprecipitation experiments followed by mass spectrometry analyses. The analyses resulted in the identification of 33 proteins, of which 24 were direct or indirect interaction partners not previously reported. The SAP interactome can be divided into categories that include apolipoproteins, the complement system, coagulation, and proteolytic regulation.

Therapeutic Clearance of Amyloid by Antibodies to Serum Amyloid P Component.

BACKGROUND: The amyloid fibril deposits that cause systemic amyloidosis always contain the nonfibrillar normal plasma protein, serum amyloid P component (SAP). The drug (R)-1-[6-[(R)-2-carboxy-pyrrolidin-1-yl]-6-oxo-hexanoyl]pyrrolidine-2-carboxylic acid (CPHPC) efficiently depletes SAP from the plasma but leaves some SAP in amyloid deposits that can be specifically targeted by therapeutic IgG anti-SAP antibodies. In murine amyloid A type amyloidosis, the binding of these antibodies to the residual SAP in amyloid deposits activates complement and triggers the rapid clearance of amyloid by macrophage-derived multinucleated giant cells. METHODS: We conducted an open-label, single-dose-escalation, phase 1 trial involving 15 patients with systemic amyloidosis. After first using CPHPC to deplete circulating SAP, we infused a fully humanized monoclonal IgG1 anti-SAP antibody. Patients with clinical evidence of cardiac involvement were not included for safety reasons. Organ function, inflammatory markers, and amyloid load were monitored. RESULTS: There were no serious adverse events. Infusion reactions occurred in some of the initial recipients of larger doses of antibody; reactions were reduced by slowing the infusion rate for later patients. At 6 weeks, patients who had received a sufficient dose of antibody in relation to their amyloid load had decreased liver stiffness, as measured with the use of transient elastography. These patients also had improvements in liver function in association with a substantial reduction in hepatic amyloid load, as shown by means of SAP scintigraphy and measurement of extracellular volume by magnetic resonance imaging. A reduction in kidney amyloid load and shrinkage of an amyloid-laden lymph node were also observed. CONCLUSIONS: Treatment with CPHPC followed by an anti-SAP antibody safely triggered clearance of amyloid deposits from the liver and some other tissues. (Funded by GlaxoSmithKline; ClinicalTrials.gov number, NCT01777243.).

Targeting chemotherapy-induced PTX3 in tumor stroma to prevent the progression of drug-resistant cancers.

The tumor microenvironment has been suggested to participate in tumorigenesis, but the nature of the communication between cancer cells and the microenvironment, especially in response to anticancer drugs, remains obscure. We determined that activation of the CCAAT/enhancer binding protein delta (CEBPD) response to Cisplatin and 5-Fluorouracil in cancer-associated macrophages and fibroblasts contributed to the metastasis, invasion, acquired chemoresistance and stemness of cancer cells by in vitro and in vivo assays. Specifically, reporter and in vivo DNA binding assays were used to determine that Pentraxin 3 (PTX3) is a CEBPD responsive gene and serves a protumor role upon anticancer drug treatment. Finally, a PTX3 peptide inhibitor RI37 was developed and assessed the antitumor effects by in vivo assays. RI37 could function as a promising inhibitor for preventing cancer progression and the metastasis, invasion and progression of drug-resistant cancers. The identification of PTX3 provided a new insight in the interaction between host and tumor and the RI37 peptide showed a great opportunity to largely reduce the risk of invasion and metastasis of cancer and drug-resistant cancers.

Pentraxin-3 Silencing Suppresses Gastric Cancer-related Inflammation by Inhibiting Chemotactic Migration of Macrophages.

BACKGROUND: Chronic inflammation characterized by the recruitment and activation of macrophages has been implicated in the development of gastric cancer. MATERIALS AND METHODS: Expression of the long form of pentraxin-3 (PTX3) in gastric cancer cells was examined by reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. The migratory capacity of gastric cancer cells and chemotaxis of macrophages by PTX3 were assessed by wound-healing and transwell assays. PTX3 silencing using small interfering RNA (siRNA) was performed to confirm PTX3-mediated effects. RESULTS: We demonstrated that PTX3 expression was elevated in human advanced gastric cancer tissues with increased infiltration of CD11b+ macrophages. Tumor necrosis factor-alpha increased PTX3 expression via nuclear factor-kappa B activation in human gastric cancer cells. PTX3 promoted the tumor cell migratory potential, the recruitment of macrophages and their subsequent binding to gastric cancer cells. These effects were suppressed by PTX3 knockdown using siRNA. CONCLUSION: Our findings suggest that gastric cancer-derived PTX3 promotes macrophage recruitment, which may contribute to gastric cancer-related inflammation.

Atorvastatin reduces long pentraxin 3 expression in vascular cells by inhibiting protein geranylgeranylation.

BACKGROUND: The long pentraxin PTX3 is an acute-phase multi-functional protein that might play both positive and detrimental effects under different pathophysiological conditions. We previously showed that statins down-regulate the release of PTX3 in human endothelial cells (ECs). The present study investigated the mechanism mediating this effect, its occurrence in other cells involved in atherogenesis, and whether it takes place in experimental atherosclerosis. METHODS AND RESULTS: We found that atorvastatin (1-5 µmol/L) decreased the production and release of PTX3 in human ECs through a post-transcriptional effect. Co-incubation with mevalonate or geranylgeranyl pyrophosphate prevented this effect. Direct blockade of geranylgeranyl transferase I by GGTI-286, treatment with the Rac inhibitor NSC23766 or silencing of the geranylgeranylated GTPase Rac2 by siRNA closely mimicked the action of atorvastatin. In contrast, inactivation of other geranylgeranylated proteins such as RhoA, RhoB, and RhoC or Rac1 did not affect PTX3 release. In addition, we found that atorvastatin also decreased PTX3 secretion in aortic SMCs through a mechanism likely dependent on protein geranylgeranylation, while no effect was observed in monocytes. Finally, we found that atherosclerotic lesions from cholesterol-fed rabbits treated with atorvastatin (2.5 mg/kg/day for 8 weeks) showed less immunoreactive PTX3 than lesions from control animals. CONCLUSIONS: Results suggest that statins may interfere with PTX3 expression in vascular cells via inhibition of protein geranylgeranylation. Since PTX3 is increasingly regarded as an important mediator of the inflammatory response underlying atherosclerosis and its complications, these results highlight the need for further studies of the role of PTX3 and its potential pharmacological modulation in cardiovascular disease.

Design, synthesis and evaluation of novel diaryl pyrrolopyrimidine and pyrrolothiazine derivatives as inhibitors of tumor necrosis factor stimulated gene-14 (TSG-14) production.

A novel series of pyrrolothiazines 2-4 and pyrrolopyrimidines 5-7 have been synthesized. The structures of these compounds were established by spectroscopic and element microanalytical data. The newly synthesized compounds were evaluated as inhibitors of TSG-14. The most effective results were obtained by the S-sec-butyl derivatives 6e (80%) and the N-ethyl derivatives 4e (70%).

Effects of the dual TP receptor antagonist and thromboxane synthase inhibitor EV-077 on human endothelial and vascular smooth muscle cells.

The prothrombotic mediator thromboxane A2 is derived from arachidonic acid metabolism through the cyclooxygenase and thromboxane synthase pathways, and transduces its effect through the thromboxane prostanoid (TP) receptor. The aim of this study was to determine the effect of the TP receptor antagonist and thromboxane synthase inhibitor EV-077 on inflammatory markers in human umbilical vein endothelial cells and on human coronary artery smooth muscle cell proliferation. To this end, mRNA levels of different proinflammatory mediators were studied by real time quantitative PCR, supernatants were analyzed by enzyme immune assay, and cell proliferation was assessed using WST-1. EV-077 significantly decreased mRNA levels of ICAM-1 and PTX3 after TNFα incubation, whereas concentrations of 6-keto PGF1α in supernatants of endothelial cells incubated with TNFα were significantly increased after EV-077 treatment. Although U46619 did not alter coronary artery smooth muscle cell proliferation, this thromboxane mimetic enhanced the proliferation induced by serum, insulin and growth factors, which was significantly inhibited by EV-077. In conclusion, EV-077 inhibited TNFα-induced endothelial inflammation and reduced the enhancement of smooth muscle cell proliferation induced by a thromboxane mimetic, supporting that the thromboxane pathway may be associated with early atherosclerosis in terms of endothelial dysfunction and vascular hypertrophy.

Neonatal levels of acute phase proteins and later risk of non-affective psychosis.

Mounting evidence suggests that immune disturbances in early life may be implicated in the etiology of non-affective psychoses. Our aim was to assess the levels of neonatal acute phase proteins (APPs), central to innate immune function as well as central nervous system development, in neonatal dried blood spots and their association with later risk of non-affective psychoses. This case-control study included 196 individuals with a verified register-based diagnosis of non-affective psychosis and 502 controls matched on age, sex and hospital of birth. Concentrations of nine different APPs were measured in eluates from dried blood spots using a bead-based multiplex assay. Odds ratios (OR) for non-affective psychoses were calculated for log(2)-transformed (continuous) as well as tertiles of APP concentrations. In continuous analysis, higher concentrations of two APPs, tissue plasminogen activator (tPA; OR: 0.90, 95% confidence interval (CI): 0.85-0.96) and serum amyloid P (SAP; OR: 0.88, 95% CI: 0.78-0.99) were protective in terms of risk of non-affective psychosis. These relationships were not affected by the addition of covariates relevant to maternal health, pregnancy and delivery to the model. Tertile analysis confirmed a protective relationship for higher levels of tPA and SAP, as well as for procalcitonin (highest tertile OR: 0.54, 95% CI:0.32-0.91). Our results suggest that persons who develop non-affective psychoses have lower levels of certain APPs at the time of birth. These differences may render individuals more susceptible to infectious diseases or cause deficiencies in pathways critical for neurodevelopment.

Serum amyloid A (SAA) induces pentraxin 3 (PTX3) production in rheumatoid synoviocytes.

OBJECTIVE: Pentraxin 3 (PTX3) is an acute-phase reactant that is involved in amplification of the inflammatory response and innate immunity. In the present study, we evaluated the relationship between PTX3 and serum amyloid A (SAA), another acute-phase reactant, in rheumatoid synoviocytes. METHODS: PTX3 mRNA expression was examined by reverse transcription polymerase chain reaction, and PTX3 protein was measured by enzyme-linked immunosorbent assay. RESULTS: SAA induced PTX3 mRNA and PTX3 protein expression in rheumatoid synoviocytes. SAA-induced PTX3 expression was attenuated when rheumatoid synoviocytes were nucleofected with N-formyl peptide receptor ligand-1 (FPRL-1)-specific siRNA, suggesting the involvement of FPRL-1. Furthermore, SAA-induced PTX3 expression was inhibited by NF-κB or mitogen-activated protein kinase-specific inhibitors. Neither soluble TNF receptor (etanercept) nor recombinant IL-1 receptor antagonist affected PTX3 production by SAA-stimulated synoviocytes, suggesting that SAA directly induces PTX3. CONCLUSION: Our data suggest that SAA plays a role in the proinflammatory and immune responses in rheumatoid synovium by inducing PTX3. We provide the first evidence that the acute-phase reactant SAA, which is produced systemically by hepatocytes, perpetuates the rheumatoid inflammatory processes by inducing another proinflammatory molecule, PTX3, locally in rheumatoid synovial tissues.

Brain serum amyloid P levels are reduced in individuals that lack dementia while having Alzheimer's disease neuropathology.

The neuropathological signs of Alzheimer's disease (AD) include beta amyloid plaques and neurofibrillary tangles. There is a significant population of individuals that have these key hallmarks but show no signs of cognitive impairment, termed non-demented with AD neuropathology (NDAN). The protective mechanism allowing these individuals to escape dementia is unknown. Serum amyloid P (SAP) is a serum protein associated with wound repair that is elevated in the brains of Alzheimer's patients and binds to amyloid plaques. Using immunoblotting and immunohistochemistry, we evaluated SAP levels in postmortem samples of hippocampus and frontal cortex in age-matched controls, AD, and NDAN individuals. AD individuals had significantly increased SAP levels compared to normal controls, while NDAN samples had no significant difference in SAP levels compared to normal controls. Our results suggest that low levels of SAP in plaques marks the brains of individuals that escape dementia despite the presence of beta amyloid plaques and tangles.

Immunoradiometric assay for human serum amyloid P component.

Human serum amyloid P component (SAP) is of increasing interest for its possible pathogenic role in amyloidosis and Alzheimer's disease, and as a therapeutic target in these conditions. We have developed and validated a robust and reproducible immunoradiometric assay (IRMA) for human SAP in serum, plasma and cerebrospinal fluid, and characterized the notable stability of human SAP immunoreactivity during storage of undiluted serum at 4°C and 37°C as well as frozen at -30°C. SAP values were also stable after repeated freeze thawing of highly diluted serum samples. The 100 fold dynamic range of the assay, 0.5-50 µg/L, encompassed all values seen in blood and cerebrospinal fluid, when tested at suitable dilutions, from both normal healthy individuals and patients, including subjects receiving the SAP-depleting drug, CPHPC. Furthermore by comparing the IRMA values in the presence and absence of calcium, the new assay revealed interference due to the binding of CPHPC by SAP, which was markedly enhanced in heparinized plasma. It is therefore essential that SAP assays in samples from patients on CPHPC be conducted in the absence of free calcium, in order to completely abrogate interference and determine the actual total SAP concentration. Estimates by the IRMA of SAP concentration in 49 serum samples from amyloidosis patients corresponded closely with those obtained by the established standard electro-immunoassay method and by a newly developed commercial ELISA kit (Hycult Biotechnology).

Geranylgeranyl-pyrophosphate regulates secretion of pentraxin 3 and monocyte chemoattractant protein-1 from rheumatoid fibroblast-like synoviocytes in distinct manners.

OBJECTIVES: We previously reported that 10 mg/day of simvastatin significantly reduced clinical scores of rheumatoid arthritis (RA) in active RA patients with hypercholesterolemia. In this study, we have investigated the mechanism by which simvastatin inhibits the production of the mediators of inflammation, such as pentraxin 3 (PTX3) and monocyte chemoattractant protein-1 (MCP-1), from fibroblast-like synoviocytes (FLS) derived from patients with RA. METHODS: FLS from RA patients were cultured with 0-10 µM simvastatin for 24 h. ELISA and real-time PCR were used to quantitate the protein level and the mRNA level of PTX3 and MCP-1, respectively. RESULTS: Simvastatin both reduced the secretion of PTX3 and MCP-1 in FLS cultures and inhibited their mRNA expression in these cells. The effects of simvastatin were all completely reversed in the presence of mevalonic acid or geranylgeranylpyrophosphate, but not in the presence of farnesyl-pyrophosphate. The geranylgeranyl transferase inhibitor GGTI-298 and the Rho kinase inhibitor Y-27632 inhibited the production of PTX3 but not of MCP-1. CONCLUSIONS: Although simvastatin inhibited the production of PTX3 and MCP-1 in RA FLS, the mechanisms were quite different. It inhibits PTX3 production in a Rho-dependent manner but MCP-1 production in a Rho-independent manner. These results shed light on novel aspects of the anti-inflammatory mechanisms of simvastatin and may prove its important role in the treatment of rheumatic diseases.

Antibodies to human serum amyloid P component eliminate visceral amyloid deposits.

Accumulation of amyloid fibrils in the viscera and connective tissues causes systemic amyloidosis, which is responsible for about one in a thousand deaths in developed countries. Localized amyloid can also have serious consequences; for example, cerebral amyloid angiopathy is an important cause of haemorrhagic stroke. The clinical presentations of amyloidosis are extremely diverse and the diagnosis is rarely made before significant organ damage is present. There is therefore a major unmet need for therapy that safely promotes the clearance of established amyloid deposits. Over 20 different amyloid fibril proteins are responsible for different forms of clinically significant amyloidosis and treatments that substantially reduce the abundance of the respective amyloid fibril precursor proteins can arrest amyloid accumulation. Unfortunately, control of fibril-protein production is not possible in some forms of amyloidosis and in others it is often slow and hazardous. There is no therapy that directly targets amyloid deposits for enhanced clearance. However, all amyloid deposits contain the normal, non-fibrillar plasma glycoprotein, serum amyloid P component (SAP). Here we show that administration of anti-human-SAP antibodies to mice with amyloid deposits containing human SAP triggers a potent, complement-dependent, macrophage-derived giant cell reaction that swiftly removes massive visceral amyloid deposits without adverse effects. Anti-SAP-antibody treatment is clinically feasible because circulating human SAP can be depleted in patients by the bis-d-proline compound CPHPC, thereby enabling injected anti-SAP antibodies to reach residual SAP in the amyloid deposits. The unprecedented capacity of this novel combined therapy to eliminate amyloid deposits should be applicable to all forms of systemic and local amyloidosis.

Molecular dissection of Alzheimer's disease neuropathology by depletion of serum amyloid P component.

New therapeutic approaches in Alzheimer's disease are urgently needed. The normal plasma protein, serum amyloid P component (SAP), is always present in cerebrospinal fluid (CSF) and in the pathognomonic lesions of Alzheimer's disease, cerebrovascular and intracerebral Abeta amyloid plaques and neurofibrillary tangles, as a result of its binding to amyloid fibrils and to paired helical filaments, respectively. SAP itself may also be directly neurocytotoxic. Here, in this unique study in Alzheimer's disease of the bis(d-proline) compound, (R)-1-[6-[(R)-2-carboxy-pyrrolidin-1-yl]-6-oxo-hexanoyl]pyrrolidine-2-carboxylic acid (CPHPC), we observed depletion of circulating SAP and also remarkable, almost complete, disappearance of SAP from the CSF. We demonstrate that SAP depletion in vivo is caused by CPHPC cross-linking pairs of SAP molecules in solution to form complexes that are immediately cleared from the plasma. We have also solved the structure of SAP complexed with phosphothreonine, its likely ligand on hyperphosphorylated tau protein. These results support further clinical study of SAP depletion in Alzheimer's disease and potentially other neurodegenerative diseases.

Ligand-assisted aggregation of proteins. Dimerization of serum amyloid P component by bivalent ligands.

A comprehensive series of solution and crystallographic studies reveal how simple, achiral, bivalent ligands of the cyclic pyruvate of glycerol promote face-to-face complex formation of the pentraxin, serum amyloid P component (SAP) into decamers. SAP, a protein of the human innate immune system, is universally present in amyloids, including cerebral amyloid deposits found in the brain of Alzheimer disease patients. Removal of SAP through a specific aggregation mechanism mediated by multivalent ligands appears to provide therapeutic benefit in the progression of this disease. Crystallographic studies reveal that in our novel series of ligands only the methyl and carboxylate moieties of the pyruvate ketal directly interact with the protein, but the geometric constraints imposed by the tether dictate which of two chair conformations are adopted by the pyruvate dioxane ring. Solution studies, as interpreted through a simple thermodynamic model, account for the distribution of pentameric and decameric bound states at different ligand concentrations and indicate that differences in the flexibility of the tether determine the geometry and stability of the specific aggregates formed between SAP and two different bivalent ligands. The factors affecting the design of ligands promoting face-to-face protein dimerization as well as potential biological implications are discussed.