OP0090 PRECLINICAL STUDIES OF A NOVEL CATHEPSIN C INHIBITOR IN MPO-ANCA-ASSOCIATED VASCULITIS MODEL

Background

MPO-ANCA-associated vasculitis (MPO-AAV) is a systemic small vessel vasculitis with the production of MPO-ANCA in the serum. This disease develops necrotizing and crescent glomerulonephritis (NCGN) and peritubular capillaritis-mediated interstitial damages in the kidneys, and pulmonary hemorrhage due to capillaritis in the lungs. Recent studies have revealed that neutrophil extracellular traps (NETs) induced by MPO-ANCA are critically involved in its pathogenesis,1 and neutrophil elastase (NE) plays an essential role in the formation of NETs.2 Cathepsin C (CatC) functions as a key enzyme in the activation process of several neutrophil serine proteases (NSPs) such as NE, proteinase 3 and cathepthin G by converting the inactive forms of the NSPs to the active forms by digesting dipeptides at the N-terminus of the enzymes.3

Objectives

Although glucocorticoids and immunosuppressive drugs used as the standard of cares can lead remission in MPO-AAV patients, there are remaining unmet medical needs such as severe side effects, resistance to the treatment and relapse. Therefore, development of new therapeutic strategies is awaited. The aim of this study is to demonstrate the efficacy of MOD06051, a novel CatC inhibitor, against MPO-AAV, using an MPO-AAV rat model established previously.4

Methods

In vitro studies: Cathpsins and NE inhibitory activity was measured using recombinant enzymes and fluorescent substrates. Cellular NE activity in the granulocytes differentiated from the primary human bone marrow-derived hematopietic stem cells under the presence or absence of MOD06051 was determined using fluorescent substrates.

In vivo studies: 4-week-old Wistar Kyoto (WKY) rats were immunized with human MPO according to Little’s protocol.4 The rats were divided into three groups (n=8 in each group), and vehicle (0.5% methylcellulose) or MOD06051 (0.3 or 3 mg/kg bid) was orally administered every day for 42 days. All rats were euthanized at the end of the study for serological and histological evaluations.

Results

In vitro studies: MOD06051 inhibited the enzymatic activity of human recombinant CatC with an IC50 value of 1.5 nM, and no other cathepsins nor NE inhibition was observed at 10 μM. The NE activity in primary human granulocytes was suppressed by MOD06051 with an IC50 value of 18 nM.

In vivo studies: MPO-ANCA was induced in all groups at the same level. The percentage of affected glomeruli including those with NCGN, NET-forming neutrophils in the peripheral blood and glomeruli, and glomerular neutrophil counts were significantly suppressed by MOD06051 treatment in a dose-dependent manner. Furthermore, hematuria score, urinary NGAL (Neutrophil Gelatinase-Associated Lipocalin), tubular erythrocyte cast counts, and pulmonary hemorrhage foci were significantly decreased in the 3 mg/kg of MOD06051 treated group with the similar trends in 0.3 mg/kg group.

Conclusion

MOD06051 showed sepcific inhibition of CatC activity. This compound suppressed the serine proteases activation in primary human neutrophils and NET formation in the MPO-AAV model rats, resulting in amelioration of MPO-ANCA-induced tissue destruction, including NCGN and tubular interstitial damages in the kidneys, and disorder of alveolar septal capillaries in the lungs. MOD06051 appears to be a promising agent for treatment of MPO-AAV patients.

References

[1]Nakazawa D, et al. Nat Rev Rheumatol 15: 91-101, 2019.

[2]Papayannopoulos V, et al. J Cell Biol 191: 677-691, 2010.

[3]Korkmaz B, et al. Pharmacol Ther 190: 202-236, 2018.

[4]Little MA, et al. Am J Pathol 174: 1212-1220, 2009.

Disclosure of Interests

Akihiro Ishizu Grant/research support from: Modulus Discovery, Inc., Mai Taniguchi: None declared, Suishin Arai: None declared, Yuka Nishibata Grant/research support from: Modulus Discovery, Inc., Sakiko Masuda Grant/research support from: Modulus Discovery, Inc., Utano Tomaru: None declared, Takafumi Shimizu Shareholder of: Modulus Discovery, Inc., Employee of: Modulus Discovery, Inc., William Sinko Shareholder of: Modulus Discovery, Inc., Employee of: Modulus Discovery, Inc., Tadashi Nagakura Shareholder of: Modulus Discovery, Inc., Employee of: Modulus Discovery, Inc., Yoh Terada Shareholder of: Modulus Discovery, Inc., Employee of: Modulus Discovery, Inc.

The Impact of c-Fos/Activator Protein-1 Inhibition on Allogeneic Pancreatic Islet Transplantation

Unpreventable allograft rejection is one of the main problems in pancreatic islet transplantation (PIT). Therefore, it is imperative to develop a more effective immunosuppressive strategy. The blockade of transcription factors has been a central part of T cell-depleting immunosuppressive therapies, as typified by the use of calcineurin inhibitors. The inhibition of activator protein-1 (AP-1) offers a novel strategy for immunosuppression in PIT, although to date, no reports on the effects of AP-1 inhibition are available. In this study, we investigated the immunosuppressive effects of T-5224, a c-Fos/AP-1-selective inhibitor, on murine T cells activated by αCD3+αCD28 mAbs. T-5224 inhibited proliferation, CD25 up-regulation, and the production of IL-2 and interferon-γ. In addition, T-5224 blocked the nuclear translocation of c-Fos/AP-1 in activated murine T cells. In BALB/c (H-2(d) )-to-C57BL/6J (H-2(b) ) mouse PIT, the 2-week administration of T-5224 prolonged survival of 600 islet allografts in a dose-dependent manner. When combined with a 2-week low-dose tacrolimus, the T-5224 treatment markedly prolonged allograft survival to over 300 days, while the efficacy was indeterminate when transplanted islet allograft mass was reduced to 300. We conclude that the c-Fos/AP-1 inhibition by T-5224 is a potentially attractive strategy for allogeneic PIT.

Combined hepatocellular carcinoma and cholangiocarcinoma growing into the common bile duct

We report a patient with combined hepatocellular carcinoma and cholangiocarcinoma (HCC-CC) growing into the common bile duct (CBD) and showing obstructive jaundice within 2 years of the onset of the disease. The patient was a 59-year-old Japanese man in whom, at the age of 57 years. a hepatic tumor was discovered by diagnostic imaging during follow-up of hepatitis B surface antigen (HBsAg)-positive liver cirrhosis. The tumor was diagnosed as HCC. Epirubicin was injected twice, intraarterially. The patient then received oral etoposide therapy for the next 14 months. The treatment was initially effective, but approximately 2 years after the hepatic tumor was discovered, local recurrence of the tumor and a tumor thrombus in the CBD were discovered. Although he was treated with percutaneous transhepatic biliary drainage (PTBD), to reduce obstructive jaundice, the jaundice was irreversible and he died of severe hepatic failure. The autopsy findings confirmed that the hepatic tumor was HCC-CC, in which the HCC and CC components expressed alpha-fetoprotein (AFP) and carbohydrate antigen 19-9 (CA19-9), respectively, which accurately reflected the disease process. The underlying mechanism of the growth of HCC-CC into the CBD may differ from the underlying mechanism of the development of icteric-type HCC.

Adult neuroblastoma of the retroperitoneum and abdomen: clinicopathologic distinction from primitive neuroectodermal tumor

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Primary extracranial meningioma of the foot: a case report

We present a rare case of primary extracranial meningioma in a 36-year-old man, who had a solitary multinodular mass located in the plantar muscle of the foot. The histology of specimens from simple excision was typical of meningioma, showing bland spindle cell proliferation with a whorl pattern. Immunohistochemical analysis demonstrated that the tumor cells showed diffuse and strong positivity for epithelial membrane antigen as well as moderate reactivity for cytokeratin and vimentin. Ultrastructurally, the tumor cells were characterized by thin bipolar cytoplasmic processes and joined by multiple small desmosomes. There were frequent pinocytotic vesicles and a distinct external lamina on the cell surface. These findings suggest that this primary ectopic meningioma, arising in the soft tissue, may have been derived from perineurial cells of the peripheral nerve, but was morphologically distinguishable from perineurioma. Primary extracranial meningioma should be included in the differential diagnosis of soft-tissue spindle cell tumors, especially those of peripheral nerve origin.

A rat model for human T lymphocyte virus type I-associated myeloneuropathy. down-regulation of bcl-2 expression and increase in sensitivity to TNF-alpha of the spinal oligodendrocytes

We reported that the tumor necrosis factor-alpha (TNF-alpha) expression and apoptotic death of oligodendrocytes appeared to be a major pathogenesis of the demyelination of spinal cords of Wistar-King-Aptekman-Hokudai (WKAH) rats with human T lymphocyte virus type I (HTLV-I) infection, HAM rats. In the present study, we examined the sensitivity to TNF-alpha-induced cell death of in vitro-separated oligodendrocytes from HTLV-I-infected WKAH rats. Although the number of non-viable oligodendrocytes increased by adding recombinant TNF-alpha, in a dose-dependent manner, in both HTLV-I-infected and uninfected control rats, oligodendrocytes from the infected rats were more susceptible to TNF-alpha. In situ detection of DNA fragmentation showed apoptotic death of oligodendrocytes. The expression of bcl-2, an anti-apoptotic gene, was strongly down-regulated in oligodendrocytes of the infected rats but not in the control rats. We suggest that the down-regulation of bcl-2 expression in the oligodendrocytes of the HTLV-I-infected rats may increase the susceptibility to TNF-alpha-induced apoptosis of oligodendrocytes, the result being development of HTLV-I-induced myeloneuropathy in rats.

Human T-lymphocyte virus type I (HTLV-I)-induced myeloneuropathy in rats: oligodendrocytes undergo apoptosis in the presence of HTLV-I

To investigate the pathogenetic role of human T-lymphocyte virus type I (HTLV-I) in central nervous system disease, a rat model for HTLV-I-associated myelopathy/tropical spastic paraparesis, designated as HAM rat disease, was examined with regard to chronological neuropathology, from early asymptomatic phase to late disease. In the thoracic spinal cord of rats with HTLV-I infection, the first event was the appearance of apoptosis of oligodendrocytes beginning at 7 months after induced infection, thereafter followed by the appearance of white matter degeneration, increase of macrophages/activated microglia and of gemistocytic astrocytes at 12, 15 and 20 months, respectively. In the spinal cord, HTLV-I provirus DNA was evident as early as 4 months after the infection, and HTLV-I pX and the tumor necrosis factor (TNF)-alpha messages began to be expressed at age 7 months, just before or at the same time as the appearance of apoptotic cells. Collective evidence suggests that the apoptotic death of oligodendrocytes, which may be induced either directly by the local expression of HTLV-I or indirectly by TNF-alpha, through the transactive function of p40Tax, is the major cause of chronic progressive myeloneuropathy in Wistar-King-Aptekman-Hokudai rats with HTLV-I infection.

A rat model of human T lymphocyte virus type I (HTLV-I) infection: in situ detection of HTLV-I provirus DNA in microglia/macrophages in affected spinal cords of rats with HTLV-I-induced chronic progressive myeloneuropathy

To investigate the pathogenetic role of human T lymphocyte virus type I (HTLV-I) in central nervous system disease, a rat model for HTLV-I-associated myelopathy/tropical spastic paraparesis, designated as HAM rat disease, has been established. Wistar-King-Aptekman-Hokudai strain rats with induced HTLV-I infection develop a chronic progressive myeloneuropathy with paraparesis of hind limbs after an incubation period of 15 months. In the affected spinal cord in these rats, white matter degeneration, demyelination and vacuolar change with microglia/macrophage infiltration are present as are the provirus DNA and the virus mRNA. To identify infected cells in the affected lesions, we carried out in situ hybridization of amplified fragments of the provirus DNA by polymerase chain reaction on thin sections, plus immunohistochemistry on the same sections. The provirus DNA was localized in some microglia/macrophages in the spinal cord lesion. In addition, the HTLV-I provirus was clearly evident not only in ED-1-negative lymphoid cells but also in ED-1-positive macrophages from lymph nodes. These observations suggest that cells of microglia/macrophage lineage may be one of dominant viral reservoirs in the spinal cords and lymph nodes in HAM rat disease. These infected microglia/macrophages may relate to cause the myeloneuropathy through neurotoxic cytokine synthesis.

HTLV-I induced myeloneuropathy in WKAH rats: apoptosis and local activation of the HTLV-I pX and TNF-alpha genes implicated in the pathogenesis

To investigate the pathogenesis of HTLV-I associated diseases, we established a rat model for HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in WKAH rats. In the spinal cords of WKAH rats carrying HTLV-I, chronological histopathology revealed the occurrence of apoptotic cell death starting at 9 months after the infection, followed by demyelination, macrophage infiltration, and the activation of astrocytes starting at 12, 15 and 20 months, respectively. Apoptosis of the Schwann cells was also observed in the peripheral nerves of these rats. By RT-PCR, pX mRNA of HTLV-I was selectively expressed in the diseased spinal cords and peripheral nerves, but not in the unaffected cerebra, cerebella, even though provirus DNAs were consistently identified in these tissues. Among several cytokines examined, mRNA expression and production of TNF-alpha were frequently detected in the spinal cord and the cerebrospinal fluid. The collective evidence suggests that the selective activation of HTLV-I, in particular Tax expression, and/or the production of TNF-alpha in target spinal cord and peripheral nerves are causally related to apoptotic death of the oligodendrocytes and Schwann cells, a major pathogenetic pathway of HTLV-I induced myeloneuropathy in the WKAH rat.

Models of HTLV-I-induced diseases. Infectious transmission of HTLV-I in inbred rats and HTVL-I env-pX transgenic rats

To examine the pathogenic roles of HTLV-I in HTLV-I-induced diseases, we developed two models; namely HTLV-I carrier rats and HTLV-I env-pX transgenic rats. Among life long HTLV-I carriers in seven rat strains, only WKAH rats with the RT1k haplotype developed chronic progressive myeloneuropathy, resembling HAM/TSP clinically and histologically in humans, designated as HAM rat disease and after long incubation periods. Apoptosis of myelin forming cells, oligodendrocytes and Schwann cells associated with HTLV-I infection appears to be the primary cause of HAM rat disease. Local activation of the pX gene and TNF alpha gene was evident in these rats. WKAH rats transgenic for HTLV-I env-pX gene were established and at age 5 weeks, swelling of the bilateral ankle joints began to develop and histological features of the affected joints resembled findings in cases of rheumatoid arthritis (RA): high-titers of rheumatoid factors were present in these rats. A series of vascular collagen diseases such as polyarteritis nodosa-like angiitis, polymyositis, myocarditis, and Sjögren's syndrome-like sialodenitis together with RA were present, even in one individual animal. These transgenic rats as well as HAM rats appear to be suitable animal models for elucidating pathogenic mechanisms implicated in HTLV-I-induced diseases and also various demyelinating vascular collagen diseases of unknown etiology.

Human T lymphocyte virus type I-induced myeloneuropathy in rats: implication of local activation of the pX and tumor necrosis factor-alpha genes in pathogenesis

The pathogenetic roles of human T lymphocyte virus type I (HTLV-I) and cytokines were investigated in HTLV-I-induced myeloneuropathy in Wistar-King-Aptekman-Hokudai rats. In the nervous system, pX messenger RNAs of HTLV-I were selectively expressed in the diseased spinal cord and peripheral nerves but not in the unaffected cerebrum and cerebellum, even though proviral DNAs were consistently identified in these tissues. Among several cytokines examined, mRNA expression and production of tumor necrosis factor (TNF)-alpha in the spinal cord and cerebrospinal fluid correlated positively with the development of spinal cord lesions. The collective evidence strongly suggests that selective activation of HTLV-I, in particular Tax expression and production of TNF-alpha induced by HTLV-I infection in target spinal cord and peripheral nerves, is causally related to apoptotic death of oligodendrocytes and Schwann cells, a major pathogenetic pathway of the HTLV-I-induced myeloneuropathy.

[HAM rat disease: an animal model of HTLV-I infection]

We have established a model of HTLV-I infection in the WKAH rat strain. By inoculating MT-2, an HTLV-I producing human T cell line, HAM rat disease, a demyelinating disease resembling human HAM/TSP, developed in the WKAH rat strain. The affected lesion in the HAM rat disease is distributed symmetrically in the lateral and anterior funiculi of the thoratic spinal cord similar to that of HAM/TSP, and the histological features are also mimicked except for infiltration of lymphocytes. Using this model, it is suggested that the apoptosis of oligodendrocyte appears to be the most important process implicated in the demyelinating process of the spinal cord. The pathogenesis of HAM/TSP is also discussed herein.