Chronic restraint stress and social transfer of stress produce tactile allodynia mediated by the HMGB1/TNFα/TNFR1 pathway in female and male rats.

Previous studies have shown the relevance of high mobility group box 1 protein (HMGB1) and tumor necrosis factor α (TNFα) in nerve or tissue injury-induced nociception. However, the role of these proteins in chronic stress and social transfer of stress (STS)-induced dysfunctional pain is not entirely known. The aim of this study was to determine the participation of the spinal HMGB1-TNFα signaling pathway and TNFα receptor 1 (TNFR1) in rats subjected to chronic restraint stress (CRS) and STS. Non-stressed female and male rats in contact with CRS rats increased sniffing behavior of the anogenital area, behavior related to STS. Rats subjected to CRS and STS reduced 50 % withdrawal threshold and reached the value of tactile allodynia after 21 days of stress. Rats return to the basal withdrawal threshold after 30 days without stress and return to allodynia values in only 5 days of stress sessions (priming). Female and male rats subjected to 28 days of CRS or STS were intrathecal injected with glycyrrhizin (inhibitor of HMGB1), thalidomide (inhibitor of the TNFα synthesis), and R7050 (TNFR1 antagonist), in all the cases, an antiallodynic effect was observed. Rats under CRS or STS enhanced HMGB1 and TNFR1 protein expression in DRG and dorsal spinal cord. Data suggest that the spinal HMGB1/TNFα/TNFR1 signaling pathway plays a relevant role in the maintenance of CRS and STS-induced nociceptive hypersensitivity in rats. These proteins could be helpful in developing pain treatments for fibromyalgia in humans.

Isorhamnetin inhibits inflammatory response to alleviate DHEA-induced polycystic ovary syndrome in rats.

OBJECTIVE: To explore the role of isorhamnetin on polycystic ovary syndrome (PCOS) in rats. METHODS: Sprague Dawley (SD) rats were subcutaneously injected with dehydroepiandrosteron (DHEA) to establish PCOS model. Hematoxylin and eosin (H&E) staining and TdT-mediated dUTP Nick-End Labeling (TUNEL) were used to measure histological changes and apoptosis of ovary tissues. The levels of serum hormones and inflammatory factors in ovary tissues were measured by enzyme-linked immuno sorbent assay (ELISA). RESULTS: In DHEA-induced PCOS rats, the levels of serum glucose, insulin, testosterone and luteinizing hormone (LH) were enhanced, estradiol (E2), sex hormone-binding globulin (SHBG), follicle stimulating hormone (FSH) levels were decreased, inflammatory levels and apoptosis of ovary tissues were increased. Additionally, DHEA increased the body weight, ovary weight, and ovary volume, cystic follicles, and decreased corpus luteum. Moreover, the tumor necrosis factor (TNF) signaling pathway was activated in PCOS rats. The levels of TNF receptor superfamily member 1 A (TNFR1), TNF-α, and fas cell surface death feceptor (FAS) were enhanced in ovary tissues of DHEA induced PCOS rats. Isorhamnetin (ISO) treatment after DHEA modeling markedly reduced serum levels of glucose, insulin, testosterone and LH, increased E2, SHBG, FSH level, decreased inflammatory levels, and inhibited apoptosis and decreased body weight, ovary weight, and ovary volume. The levels of TNFR1, TNF-α, and FAS were markedly decreased after ISO treatment in PCOS rats. Additionally, ISO alone had no significant effect on rats. CONCLUSION: Isorhamnetin inhibits inflammatory response to alleviate DHEA-induced PCOS in rats by inactivating the TNF signaling pathway.

Estrogen receptor beta activity contributes to both tumor necrosis factor alpha expression in the hypothalamic paraventricular nucleus and the resistance to hypertension following angiotensin II in female mice.

Sex differences in the sensitivity to hypertension and inflammatory processes are well characterized but insufficiently understood. In male mice, tumor necrosis factor alpha (TNFα) in the hypothalamic paraventricular nucleus (PVN) contributes to hypertension following slow-pressor angiotensin II (AngII) infusion. However, the role of PVN TNFα in the response to AngII in female mice is unknown. Using a combination of in situ hybridization, high-resolution electron microscopic immunohistochemistry, spatial-temporal gene silencing, and dihydroethidium microfluorography we investigated the influence of AngII on both blood pressure and PVN TNFα signaling in female mice. We found that chronic (14-day) infusion of AngII in female mice did not impact blood pressure, TNFα levels, the expression of the TNFα type 1 receptor (TNFR1), or the subcellular distribution of TNFR1 in the PVN. However, it was shown that blockade of estrogen receptor ß (ERß), a major hypothalamic estrogen receptor, was accompanied by both elevated PVN TNFα and hypertension following AngII. Further, AngII hypertension following ERß blockade was attenuated by inhibiting PVN TNFα signaling by local TNFR1 silencing. It was also shown that ERß blockade in isolated PVN-spinal cord projection neurons (i.e. sympathoexcitatory) heightened TNFα-induced production of NADPH oxidase (NOX2)-mediated reactive oxygen species, molecules that may play a key role in mediating the effect of TNFα in hypertension. These results indicate that ERß contributes to the reduced sensitivity of female mice to hypothalamic inflammatory cytokine signaling and hypertension in response to AngII.

High Serum Tumor Necrosis Factor Receptor 1 Levels Are Related to Risk of Low Intrinsic Capacity in Elderly Adults.

OBJECTIVES: To explore the association between inflammatory cytokines and intrinsic capacity in older adults. METHOD: Data were retrieved from the Cardiovascular Health, Cognition and Aging Study. A total of 130 participants aged 60-99 years (mean age 73.11±9.02 years) were recruited. Intrinsic capacity was assessed by the five domains recommended by the World Health Organization: locomotion, cognition, vitality, sensory and psychological domains. Circulating interleukin-6, tumor necrosis factor receptor 1 (TNFR1), insulin-like growth factor-1, and vaspin levels were measured. Logistic regression was conducted for factors associated with intrinsic capacity decline. RESULTS: Intrinsic capacity decline was associated with older age, kidney diseases, olfactory disturbances and lower grip strength. Logistic regression showed that circulating TNFR1 was independently associated with intrinsic capacity decline after adjustments for age, sex, education, chronic diseases, grip strength, and physical activity. CONCLUSION: Elevated circulating TNFR1 levels are independently associated with declined intrinsic capacity, suggesting that chronic inflammation may underlie intrinsic capacity decline.

A20 protects cells from TNF-induced apoptosis through linear ubiquitin-dependent and -independent mechanisms.

The cytokine TNF promotes inflammation either directly by activating the MAPK and NF-κB signaling pathways, or indirectly by triggering cell death. A20 is a potent anti-inflammatory molecule, and mutations in the gene encoding A20 are associated with a wide panel of inflammatory pathologies, both in human and in the mouse. Binding of TNF to TNFR1 triggers the NF-κB-dependent expression of A20 as part of a negative feedback mechanism preventing sustained NF-κB activation. Apart from acting as an NF-κB inhibitor, A20 is also well-known for its ability to counteract the cytotoxic potential of TNF. However, the mechanism by which A20 mediates this function and the exact cell death modality that it represses have remained incompletely understood. In the present study, we provide in vitro and in vivo evidences that deletion of A20 induces RIPK1 kinase-dependent and -independent apoptosis upon single TNF stimulation. We show that constitutively expressed A20 is recruited to TNFR1 signaling complex (Complex I) via its seventh zinc finger (ZF7) domain, in a cIAP1/2-dependent manner, within minutes after TNF sensing. We demonstrate that Complex I-recruited A20 protects cells from apoptosis by stabilizing the linear (M1) ubiquitin network associated to Complex I, a process independent of its E3 ubiquitin ligase and deubiquitylase (DUB) activities and which is counteracted by the DUB CYLD, both in vitro and in vivo. In absence of linear ubiquitylation, A20 is still recruited to Complex I via its ZF4 and ZF7 domains, but this time protects the cells from death by deploying its DUB activity. Together, our results therefore demonstrate two distinct molecular mechanisms by which constitutively expressed A20 protect cells from TNF-induced apoptosis.

Clinical development of onercept, a tumor necrosis factor binding protein, in psoriasis.

BACKGROUND: Tumor necrosis factor (TNF)-α plays a critical role in psoriasis pathogenesis, and several anti-TNF agents have been developed as therapeutic drugs in this indication. SCOPE: To present the preclinical rationale and clinical data for onercept, a novel anti-TNF agent developed for the treatment of moderate-to-severe psoriasis, and to critically evaluate the onercept clinical development program. FINDINGS: Onercept was shown in preclinical studies to inhibit TNF-α and suppress clinical signs in several inflammatory conditions. In phase II studies onercept demonstrated a therapeutic benefit in psoriasis and psoriatic arthritis and no safety issues were identified. Based on these results, a phase III program comprising three multicenter, randomized, double-blind, placebo-controlled studies examining onercept in moderate-to-severe plaque psoriasis was initiated. Following the occurrence of two cases of systemic inflammatory response syndrome (SIRS) and lower than expected efficacy results, an independent Data Safety Monitoring Board (DSMB) determined that the risk-benefit ratio was not sufficiently favorable to justify continued development, and all clinical studies were promptly terminated. Although not initially diagnosed as such by the investigators, two further SIRS events were reported, one after study discontinuation. Although an increased incidence of infection and sepsis-like events has been associated with other anti-TNF therapies, an increased risk of infection was not observed with onercept treatment. Moreover, no infectious etiology was determined in the SIRS cases. The data suggest that the SIRS reactions were due to a systemic inflammatory response. CONCLUSIONS: Despite promising early clinical results, onercept showed many of the expected risks associated with other anti-TNF agents and proved not to have an exceptional efficacy and safety profile. The clinical development of onercept highlights the critical importance of DSMBs and closely monitoring patient safety and evaluating risk-benefit profiles in large clinical programs.

Synovial tissue and serum biomarkers of disease activity, therapeutic response and radiographic progression: analysis of a proof-of-concept randomised clinical trial of cytokine blockade.

OBJECTIVES: To evaluate synovial tissue and serum biomarkers of disease activity, therapeutic response and radiographic progression during biological therapy for rheumatoid arthritis (RA). METHODS: Patients with active RA entered a randomised study of anakinra 100 mg/day, administered as monotherapy or in combination with pegsunercept 800 microg/kg twice a week. Arthroscopic synovial tissue biopsies were obtained at baseline and two further time points. Following immunohistochemical staining, selected mediators of RA pathophysiology were quantified using digital image analysis. Selected mediators were also measured in the serum. RESULTS: Twenty-two patients were randomly assigned: 11 received monotherapy and 11 combination therapy. American College of Rheumatology 20, 50 and 70 response rates were 64%, 64% and 46% with combination therapy and 36%, 9% and 0% with monotherapy, respectively. In synovial tissue, T-cell infiltration, vascularity and transforming growth factor beta (TGFbeta) expression demonstrated significant utility as biomarkers of disease activity and therapeutic response. In serum, interleukin 6 (IL-6), matrix metalloproteinase (MMP) 1, MMP-3 and tissue inhibitor of metalloproteinase 1 (TIMP-1) were most useful in this regard. An early decrease in serum levels of TIMP-1 was predictive of the later therapeutic outcome. Pretreatment tissue levels of T-cell infiltration and the growth factors vascular endothelial growth factor/TGFbeta, and serum levels of IL-6, IL-8, MMP-1, TIMP-1, soluble tumour necrosis factor receptor types I and II and IL-18 correlated with radiographic progression. CONCLUSIONS: Synovial tissue analysis identified biomarkers of disease activity, therapeutic response and radiographic progression. Biomarker expression in tissue was independent of the levels measured in the serum.