Blockade of tumor necrosis factor-α converting enzyme (TACE) enhances IL-1β and IFN-γ via caspase-1 activation: a probable cause for loss of efficacy of TACE inhibitors in humans?

Neonatal inflammatory skin and bowel disease type 1 caused by a complex genetic defect and responsive to combined anti-TNF-alpha and IL-12/23 blockade

ADAM17, encoding ADAM metallopeptidase domain 17, is a membrane-bound shedding protease which plays an essential role during normal development and in the regulation of inflammation. Bi-allelic variants in ADAM17, resulting in complete loss of ADAM17 expression, have been reported in individuals affected by the rare neonatal inflammatory skin and bowel disease 1 (NISBD1). We report here on a young female individual with NISBD1 featuring erythroderma, atrichia, nail dystrophy, esophageal strictures, intractable diarrhea, profound failure to thrive and recurrent cutaneous and systemic infections. NISBD1 was found in this case to result from a complex compound heterozygous defect consisting of a large genomic deletion spanning exons 6 and 7 as well as a splice site variant causing exon 17 skipping. Skin manifestations dramatically improved in response to combined anti-TNF-alpha and IL-12/23 blockade while gastrointestinal symptoms were controlled with budesonide. Our study further expands the phenotypic and genetic spectrum of NISBD1 type 1 and suggests that combined immunosuppressive treatments may be indicated in this complex condition.

Differed IL-1 Beta Response between Active TB and LTBI Cases by Ex Vivo Stimulation of Human Monocyte-Derived Macrophage with TB-Specific Antigen

Background

The difference of macrophage-specific interleukin-1 beta (IL-1b) response between latent tuberculosis infection (LTBI) and active tuberculosis (TB) remains less studied.

Method

We performed this prospective study and recruited active TB patients, contacts with LTBI, and uninfected contacts. The gene and protein expression of human monocyte-derived macrophage (hMDM) after ex vivo stimulation by early secretory antigenic target-6KD (ESAT-6) and tuberculin purified protein derivatives (PPD) was studied by real-time PCR and flow cytometry. The effect of caspase-1 inhibitor was also studied.

Result

The IL-1b gene expression after 6 hr ESAT-6 1 μg/ml stimulation was different among active TB patients (n = 12), LTBI cases (n = 12), and uninfected contacts (n = 23) (log fold change: 0.98 ± 1.26 vs. 2.20 ± 0.96 vs. 2.20 ± 0.96, P = 0.013). The IL-1b gene expression at 24 hours was higher than that at 6 hours in LTBI cases (n = 4) and uninfected contacts (n = 6). After 24 hr ESAT-6 1 μg/ml stimulation, the percentage of IL-1b-expressed hMDM was borderline lower in the active TB patients (n = 9) than in the LTBI cases (n = 10) (14.0 ± 11.2% vs. 31.6 ± 22.5%, P = 0.065). Compared with ESAT-6 1 μg/ml stimulation but without the addition of caspase-1 inhibitor (CasI) (55.6 ± 16.3%), the percentage of IL-1b-positive hMDMs decreased after addition of CasI (50 μg/ml CasI: 49.8 ± 18.2%, P = 0.078; 100 μg/ml CasI: 46.6 ± 20.8%, P = 0.030; 150 μg/ml CasI: 33.7 ± 15.5%, P = 0.016).

Conclusions

This study revealed that macrophage-specific IL-1b response differed among different stages of Mycobacterium tuberculosis infection. The role of IL-1b and inflammasome in the process of LTBI progressing to active TB warrants further investigation.

Loss of ADAM17 is associated with severe multiorgan dysfunction

ADAM metallopeptidase domain 17 (ADAM17) is responsible for processing large numbers of proteins. Recently, 1 family involving 2 patients with a homozygous mutation in ADAM17 were described, presenting with skin lesions and diarrhea. In this report, we describe a second family confirming the existence of this syndrome. The proband presented with severe diarrhea, skin rash, and recurrent sepsis, eventually leading to her death at the age of 10 months. We performed exome sequencing and detailed pathological and immunological investigations. We identified a novel homozygous frameshift mutation in ADAM17 (NM_003183.4:c.308dupA) leading to a premature stop codon. CD4(+) and CD8(+) T-cell stimulation assays showed severely diminished tumor necrosis factor-α and interleukin-2 production. Skin biopsies indicated a focal neutrophilic infiltrate and spongiotic dermatitis. Interestingly, the patient developed unexplained systolic hypertension and nonspecific hepatitis with apoptosis. This report provides evidence for an important role of ADAM17 in human immunological response and underscores its multiorgan involvement.

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Selective inhibition of tumor necrosis factor-α converting enzyme attenuates liver toxicity in a murine model of concanavalin A induced auto-immune hepatitis

Emerging evidence suggest that tumor necrosis factor (TNF)-α plays a major role in pathogenesis of auto-immune hepatitis (AIH) induced liver injury. Blockade of TNF-α synthesis or bio-activity protects against experimental AIH. TNF-α converting enzyme (TACE) is a member of the ADAM (a disintegrin and metalloproteinase) family which processes precursor TNF-α to release soluble TNF-α. We hypothesized that selective inhibition of TACE might protect AIH. To investigate this, we studied the effects of a selective TACE inhibitor DPC-333 on murine model of liver injury and fibrosis induced with concanavalin A (Con A). Pre-treatment with DPC-333 significantly suppressed plasma alanine transaminase, aspartate transaminase and cytokines such as TNF-α, interferon (IFN)-γ, interleukin (IL)-2 and IL-6 levels due to acute Con A challenge. Interestingly; DPC-333 inhibited liver poly (ADP-ribose) polymerase (PARP)-1 activity which was associated with reduced number of necrotic hepatocytes in histological examination and mortality associated with Con A. In fibrosis study, repeated Con A administration significantly up-regulated liver collagen deposition as assessed by measurement of hydroxyproline content which was further confirmed in liver histology with Masson's trichrome staining. Treatment with 30mg/kg of DPC-333 was able to suppress liver hydroxyproline and fibrous tissue proliferation which corroborated well with inhibition in expression of pro-fibrotic genes such as tissue inhibitor of metalloproteinase (TIMP)-1 and transforming growth factor (TGF)-β1. These observations suggest that selective TACE inhibition is an effective approach for the treatment of both immune mediated hepatic inflammation and fibrosis.