Gut microbiome and metabolome to discover pathogenic bacteria and probiotics in ankylosing spondylitis.

Objective: Previous research has partially revealed distinct gut microbiota in ankylosing spondylitis (AS). In this study, we performed non-targeted fecal metabolomics in AS in order to discover the microbiome-metabolome interface in AS. Based on prospective cohort studies, we further explored the impact of the tumor necrosis factor inhibitor (TNFi) on the gut microbiota and metabolites in AS. Methods: To further understand the gut microbiota and metabolites in AS, along with the influence of TNFi, we initiated a prospective cohort study. Fecal samples were collected from 29 patients with AS before and after TNFi therapy and 31 healthy controls. Metagenomic and metabolomic experiments were performed on the fecal samples; moreover, validation experiments were conducted based on the association between the microbiota and metabolites. Results: A total of 7,703 species were annotated using the metagenomic sequencing system and by profiling the microbial community taxonomic composition, while 50,046 metabolites were identified using metabolite profiling. Differential microbials and metabolites were discovered between patients with AS and healthy controls. Moreover, TNFi was confirmed to partially restore the gut microbiota and the metabolites. Multi-omics analysis of the microbiota and metabolites was performed to determine the associations between the differential microbes and metabolites, identifying compounds such as oxypurinol and biotin, which were correlated with the inhibition of the pathogenic bacteria Ruminococcus gnavus and the promotion of the probiotic bacteria Bacteroides uniformis. Through experimental studies, the relationship between microbes and metabolites was further confirmed, and the impact of these two types of microbes on the enterocytes and the inflammatory cytokine interleukin-18 (IL-18) was explored. Conclusion: In summary, multi-omics exploration elucidated the impact of TNFi on the gut microbiota and metabolites and proposed a novel therapeutic perspective: supplementation of compounds to inhibit potential pathogenic bacteria and to promote potential probiotics, therefore controlling inflammation in AS.

Targeting AQP9 enhanced the anti-TNF therapy response in Crohn's disease by inhibiting LPA-hippo pathway.

Although anti-TNF antibodies are extensively used to treat Crohn's disease (CD), a significant proportion of patients, up to 40%, exhibit an inadequate response to this therapy. Our objective was to identify potential targets that could improve the effectiveness of anti-TNF therapy in CD. Through the integration and analysis of transcriptomic data from various CD databases, we found that the expression of AQP9 was significantly increased in anti-TNF therapy-resistant specimens. The response to anti-TNF therapy in the CD mouse model was significantly enhanced by specifically inhibiting AQP9. Further experiments found that the blockade of AQP9, which is dominantly expressed in macrophages, decreased inflamed macrophage functions and cytokine expression. Mechanistic studies revealed that AQP9 transported glycerol into macrophages, where it was metabolized to LPA, which was further metabolized to LPA, resulting in the activation of the LPAR2 receptor and downstream hippo pathway, finally promoting the expression of cytokines, especially IL23 and IL1ß⊡ Taken together, the expansion of AQP9+ macrophages is associated with resistance to anti-TNF therapy in Crohn's disease. These findings indicated that AQP9 could be a potential target for enhancing anti-TNF therapy in Crohn's disease.

A TNF-α inhibitor abolishes sepsis-induced cognitive impairment in mice by modulating acetylcholine and nitric oxide homeostasis, BDNF release, and neuroinflammation.

Neurodegenerative disorders have a pathophysiology that heavily involves neuroinflammation. In this study, we used lipopolysaccharide (LPS) to create a model of cognitive impairment by inducing systemic and neuroinflammation in experimental animals. LPS was injected intraperitoneally at a dose of 0.5 mg/kg during the last seven days of the study. Adalimumab (ADA), a TNF-α inhibitor, was injected at a dose of 10 mg/kg a total of 3 times throughout the study. On the last two days of the experiment, 50 mg/kg of curcumin was administered orally as a positive control group. Open field (OF) and elevated plus maze tests (EPM) were used to measure anxiety-like behaviors. The tail suspension test (TST) was used to measure depression-like behaviors, while the novel object recognition test (NOR) was used to measure learning and memory activities. Blood and hippocampal TNF α and nitric oxide (NO) levels, hippocampal BDNF, CREB, and ACh levels, and AChE activity were measured by ELISA. LPS increased anxiety and depression-like behaviors while decreasing the activity of the learning-memory system. LPS exerted this effect by causing systemic and neuroinflammation, cholinergic dysfunction, and impaired BDNF release. ADA controlled LPS-induced behavioral changes and improved biochemical markers. ADA prevented cognitive impairment induced by LPS by inhibiting inflammation and regulating the release of BDNF and the cholinergic pathway.

Identification of Dihydrobenzofuran Neolignans as Novel PDE4 Inhibitors and Evaluation of Antiatopic Dermatitis Efficacy in DNCB-Induced Mice Model.

Atopic dermatitis is a chronic relapsing skin disease characterized by recurrent, pruritic, localized eczema, while PDE4 inhibitors have been reported to be effective as antiatopic dermatitis agents. 3',4-O-dimethylcedrusin (DCN) is a natural dihydrobenzofuran neolignan isolated from Magnolia biondii with moderate potency against PDE4 (IC50 = 3.26 ± 0.28 µM) and a binding mode similar to that of apremilast, an approved PDE4 inhibitor for the treatment of psoriasis. The structure-based optimization of DCN led to the identification of 7b-1 that showed high inhibitory potency on PDE4 (IC50 = 0.17 ± 0.02 µM), good anti-TNF-α activity (EC50 = 0.19 ± 0.10 µM), remarkable selectivity profile, and good skin permeability. The topical treatment of 7b-1 resulted in the significant benefits of pharmacological intervention in a DNCB-induced atopic dermatitis-like mice model, demonstrating its potential for the development of novel antiatopic dermatitis agents.

Faecal Bacteriome and Metabolome Profiles Associated with Decreased Mucosal Inflammatory Activity Upon Anti-TNF Therapy in Paediatric Crohn's Disease.

BACKGROUND AND AIMS: Treatment with anti-tumour necrosis factor α antibodies [anti-TNF] changes the dysbiotic faecal bacteriome in Crohn's disease [CD]. However, it is not known whether these changes are due to decreasing mucosal inflammatory activity or whether similar bacteriome reactions might be observed in gut-healthy subjects. Therefore, we explored changes in the faecal bacteriome and metabolome upon anti-TNF administration [and therapeutic response] in children with CD and contrasted those to anti-TNF-treated children with juvenile idiopathic arthritis [JIA]. METHODS: Faecal samples collected longitudinally before and during anti-TNF therapy were analysed with regard to the bacteriome by massively parallel sequencing of the 16S rDNA [V4 region] and the faecal metabolome by 1H nuclear magnetic resonance imaging. The response to treatment by mucosal healing was assessed by the MINI index at 3 months after the treatment started. We also tested several representative gut bacterial strains for in vitro growth inhibition by infliximab. RESULTS: We analysed 530 stool samples from 121 children [CD 54, JIA 18, healthy 49]. Bacterial community composition changed on anti-TNF in CD: three members of the class Clostridia increased on anti-TNF, whereas the class Bacteroidia decreased. Among faecal metabolites, glucose and glycerol increased, whereas isoleucine and uracil decreased. Some of these changes differed by treatment response [mucosal healing] after anti-TNF. No significant changes in the bacteriome or metabolome were noted upon anti-TNF in JIA. Bacterial growth was not affected by infliximab in a disc diffusion test. CONCLUSIONS: Our findings suggest that gut mucosal healing is responsible for the bacteriome and metabolome changes observed in CD, rather than any general effect of anti-TNF.

A novel single domain bispecific antibody targeting VEGF and TNF-α ameliorates rheumatoid arthritis.

Anti-TNF-α therapy fails in 30% of patients, where TNF-α may not be the key causative factor in these patients. We developed a bispecific single-domain antibody block TNF-α and VEGF (V5-3).The experiments showed that V5-3 effectively activated proliferation and migration of RA-FLS and HUVEC, tube-forming role of HUVEC, and expression of inflammatory factors in vitro. Besides, the experiments indicated that the anti-RA activity of V5-3 was superior to Anbainuo in vivo. Application of V5-3 reduced the expression of inflammatory factors, extent of synovial inflammation and angiogenesis and attenuated the severity of autoimmune arthritis in collagen-induced arthritis (CIA) mice. Mechanistically, V5-3 suppressed p65, AKT and VEGFR2 phosphorylation, as well as production of TNF-α and VEGF in joint tissues. These results demonstrated that V5-3 displayed a superior effect of anti-RA, may be a new therapy to overcome the limitations of anti-TNF-α monoclonal antibody.

Long Non-Coding RNA Signatures in the Ileum and Colon of Crohn's Disease Patients and Effect of Anti-TNF-α Treatment on Their Modulation.

Biological therapies only benefit one-third of patients with Crohn's disease (CD). For this reason, a deeper understanding of the mechanisms by which biologics elicit their effect on intestinal mucosa is needed. Increasing evidence points toward the involvement of long noncoding RNAs (lncRNAs) in the pathogenesis of CD, although their role remains poorly studied. We aimed to characterize lncRNA profiles in the ileum and colon from CD patients and evaluate the effect of anti-TNF-α treatment on their transcription. Terminal ileum and left colon samples from 30 patients (active CD = 10, quiescent CD = 10, and healthy controls (HCs) = 10) were collected for RNA-seq. The patients were classified according to endoscopic activity. Furthermore, biopsies were cultured with infliximab, and their transcriptome was determined by Illumina gene expression array. A total of 678 differentially expressed lncRNAs between the terminal ileum and left colon were identified in HCs, 438 in patients with quiescent CD, and 468 in patients with active CD. Additionally, we identified three new lncRNAs in the ileum associated with CD activity. No differences were observed when comparing the effect of infliximab according to intestinal location, presence of disease (CD vs. HC), and activity (active vs. quiescent). The expression profiles of lncRNAs are associated with the location of intestinal tissue, being very different in the ileum and colon. The presence of CD and disease activity are associated with the differential expression of lncRNAs. No modulatory effect of infliximab has been observed in the lncRNA transcriptome.

Size Matters! Anti-HBs Titer and HBV Reactivation During Anti-TNF Therapy.

BACKGROUND AND AIMS: We and others have previously described that hepatitis B surface antibody (anti-HBs) seems to protect against clinically significant HBV reactivation in cohort studies of patients undergoing anti-tumor necrosis factor (TNF) therapy. However, there were too few cases of HBV reactivation within cohort studies to assess the role of anti-HBs titer on reactivation. The purpose of this study was to systematically review the correlation between anti-HBs titer and the degree of clinically relevant HBV reactivation in patients undergoing anti-TNF therapy. METHODS AND RESULTS: We systemically reviewed all studies discussing anti-TNF therapy in patients with resolved HBV infection, defined as hepatitis surface antigen (HBsAg) negative and hepatitis B core antibody (anti-HBc) positive. We identified a total of 48 cases of reactivation from 5 cohort studies and 10 case reports or case series; 21 were anti-HBs negative, 7 were only reported as anti-HBs positive, 16 were anti-HBs positive with titer below 100, and 4 were anti-HBs positive with titer above 100. HBsAg sero-reversion was dominantly seen in patients with negative, low and/or declining anti-HBs titers. There was a significant trend toward less clinically relevant form of reactivation with increase in baseline anti-HBs titer (p = 0.022). CONCLUSION: Anti-HBs titers greater than 100 iU/L protect against clinically relevant HBV reactivation, while patients with low anti-HBs titers or negative anti-HBs had more clinically relevant HBV reactivation and higher rates of HBsAg sero-reversion. This suggests the importance of baseline quantitative anti-HBs prior to starting anti-TNF therapy and consideration vaccination for boosting anti-HBs titers prior to and/or during therapy.

Targeting senescence and inflammation in chronic destructive TNF-driven joint pathology.

We had shown that administration of the senolytic Dasatinib abolishes arthritis in the human TNF transgenic mouse model of chronic destructive arthritis when given in combination with a sub-therapeutic dose of the anti-TNF mAb Infliximab (1 mg/kg). Herein, we found that while the number of senescent chondrocytes (GL13+/Ki67-), assessed according to guideline algorithmic approaches, was not affected by either Dasatinib or sub-therapeutic Infliximab monotherapies, their combination reduced senescent chondrocytes by 50 %, which was comparable to levels observed with therapeutic Infliximab monotherapy (10 mg/kg). This combination therapy also reduced the expression of multiple factors of senescence-associated secretory phenotype in arthritic joints. Studies to elucidate the interplay of inflammation and senescence may help in optimizing treatment strategies also for age-related pathologies characterized by chronic low-grade joint inflammation.

A macrophage plasma membrane-coated and DNA structured nanomedicine targets to alleviate rheumatoid arthritis via dual inhibition to TNF-α and NF-κB.

High heterogenicity of rheumatoid arthritis (RA) leads to poor response in many patients. Combined therapies that simultaneously inhibit multiple proinflammatory targets may improve anti-RA efficacy. However, which monotherapies to combine and how to achieve the combination are critical issues. Here, we design a macrophage plasma membrane-coated and DNA structured nanomedicine to achieve a dual inhibitory therapy to Tumor necrosis factor alpha (TNF-α) and NF-κB. An anti-NF-κB decoy oligodeoxynucleotides (dODN) is first conjugated to a DNA cage with precise numbers and locations (Cage-dODN). Meanwhile, an anti-TNF-α siRNA is anchored to extracted macrophage plasma membrane (siRNA@M). Subsequently, siRNA@M is used to encapsulate Cage-dODN to fabricate siRNA@M(Cage-dODN) (siMCO). The size and zeta potential of siMCO are 63.1 ± 15.7 nm and -20.7 ± 3.8 mV respectively. siMCO shows increased intracellular uptake by inflamed macrophages and enhanced accumulation in inflamed mouse paws. siMCO also reduces pro-inflammatory factors at genetic and protein levels, alleviates arthritic symptoms, and shows no influence to major blood components. These results show that siMCO is a potential targeted, efficient, and safe dual inhibitory therapy for the treatment of inflammatory arthritis. The macrophage plasma membrane can be utilized to improve the targeting, stability, and efficacy of DNA structured nanomedicines.

Tolerized Microglia Protect Neurons Against Endotoxin-Induced TNF-α Production via an LBP-Dependent Intracellular p38 MAPK Signaling Pathway.

The development of microglial endotoxin tolerance (ET) is a critical event in protecting neurons against excessive immune responses when microglia are administered two consecutive lipopolysaccharide (LPS) challenges. However, the intrinsic mechanisms of microglia shape ET programs and protect neurons remain unclear. This study aimed to determine whether extracellular autocrine cascades or intracellular signaling pathways are involved in ET microglia-mediated tumor necrosis factor-alpha (TNF-α) reduction and neuroprotection. Neuron-glia cultures composed of astroglia, neurons, and microglia were performed in different conditions: with or without serum or LPS-binding proteins (LBP), along with an induction approach of ET. Enzyme-linked immunosorbent assay results revealed that LPS induced TNF-α tolerance of microglia in an LBP-dependent manner. Furthermore, we determined whether the early pro-inflammatory cytokines induced by LPS might contribute to the development of microglial ET. Our data showed that the neutralization of TNF-α using an anti-TNF-α antibody had no change in the TNF-α tolerance of microglia during the ET challenge. Furthermore, pre-incubation of TNF-α, interleukin-1 beta, and prostaglandin E2 failed to induce any TNF-α tolerance in microglia after LPS treatment. Moreover, using three specific chemical inhibitors that respectively blocked the activities of the mitogen-activated protein kinases (MAPKs) namely p38, c-Jun N-terminal kinase and extracellular signal-related kinases revealed that inhibition of p38 MAPK by SB203580 disrupted the tolerated microglia-mediated TNF-α reduction and neuroprotection. In summary, our findings demonstrated that the LPS pre-treatment immediately programmed the microglial ET to prevent endotoxin-induced TNF-α production and neuronal damage through the intracellular p38 MAPK signaling pathway.

Transcriptomic profile comparison of monocytes from rheumatoid arthritis patients in treatment with methotrexate, anti-TNFa, abatacept or tocilizumab.

It is well documented that patients affected by rheumatoid arthritis (RA) have distinct susceptibility to the different biologic DMARDs available on the market, probably because of the many facets of the disease. Monocytes are deeply involved in the pathogenesis of RA and we therefore evaluated and compared the transcriptomic profile of monocytes isolated from patients on treatment with methotrexate alone or in combination with tocilizumab, anti-TNFα or abatacept and from healthy donors. Whole-genome transcriptomics yielded a list of regulated genes by Rank Product statistics and DAVID was then used for functional annotation enrichment analysis. Last, data were validated by qRT-PCR. Abatacept, tocilizumab and anti-TNFa cohorts were separately compared with methotrexate, leading to the identification of 78, 6, and 436 differentially expressed genes, respectively. The upper-most ranked genes were related to inflammatory processes and immune responses. Such an approach draws the genomic profile of monocytes in treated RA patients and lays the basis for finding gene signature for tailored therapeutic choices.

Synovial monocytes from psoriatic and rheumatoid arthritis patients are modulated differently by TNF inhibitors and glucocorticoids: an ex-vivo study.

OBJECTIVES: Synovial monocytes (expressing CD14+CD16+) affect pro-inflammatory responses in the synovium microenvironment of psoriatic arthritis (PsA) and rheumatoid arthritis (RA). The effect of various drugs on those cells was evaluated. METHODS: Synovial fluid mononuclear cells (SFMCs) from PsA (n=29) and RA (n=11) patients were cultured with biologics or glucocorticoids (GCs). CD14+CD16+ cells were analysed by flow cytometry. TNF secretion was assessed by ELISA and changes in cytokine and matrix metalloproteinase-9 (MMP-9) mRNA by qPCR. RESULTS: TNF inhibitors (i) [adalimumab (ADA) and infliximab (IFX)] significantly reduced the %CD14+CD16+ cells (p<0.04 and p<0.02, respectively) compared to IL-17Ai, IL-12/23i, and GCs in PsA patients' SFMCs. Similarly, those TNFi reduced the %CD14+CD16+ cells (p<0.05 and p<0.02, respectively) compared to IL-6Ri, CD20i and GCs in RA patients' SFMCs. TNFi (ADA p<0.01, IFX p=0.0003), and GCs (p<0.05) reduced TNF levels in PsA patients SFMCs supernatants. IFX down-regulated IL-1ß mRNA (p<0.005) while GCs betamethasone (BET) (p<0.01) and methylprednisolone acetate (MPA) (p<0.005) led to IL-1ß up-regulation. IFX down-regulated IL-8 and MMP-9 (p<0.01) and up-regulated IL-10 (p<0.005), and GCs did so to a greater extent (for IL-8, BET p<0.0001 and MPA p<0.005, for MMP-9, BET and MPA p<0.0001 and for IL-10, BET and MPA p<0.0001). CONCLUSIONS: TNFi but not GCs reduced the inflammatory monocytes. Both TNFi and GCs inhibited TNF secretion but differently modulated IL-1ß, IL-8, MMP-9 and IL-10 gene expression. Our data point to TNFi as a modulator of synovial monocytes.

The mechanisms and functions of TNF-α in intervertebral disc degeneration.

Low back pain (LBP) is one of the most common health problems in people's lives, which brings a massive burden to clinicians, and the leading cause of LBP is intervertebral disc degeneration (IDD). IDD is mainly caused by factors such as aging, mechanical stress, and lack of nutrition. The pathological mechanism of IDD is very complex, involving inflammatory response, cell metabolism disorder, and so on. Unfortunately, in the current treatment of IDD, only relieving symptoms as the primary means of relieving a patient's pain cannot effectively inhibit or reverse the progression of IDD. Tumor necrosis factor-α (TNF-α) is a multifunctional pro-inflammatory factor involved in many diseases' pathological processes. With the in-depth study of the pathological mechanism of IDD, more and more evidence has shown that TNF-α is an essential activator of IDD, which is related to the metabolic disorder, inflammatory responses, apoptosis, and other pathological processes of extracellular dissociation in the intervertebral disc. Therefore, anti-TNF-α therapy is an effective therapeutic target for alleviating IDD, especially in inhibiting extracellular matrix degradation and reducing inflammatory responses. This article reviews the pathological role of TNF-α in IDD and the latest research progress of TNF-α inhibitors in treating IDD.

Additive efficacy of a bispecific anti-TNF/IL-6 nanobody compound in translational models of rheumatoid arthritis.

Rheumatoid arthritis (RA) is one of the most common autoimmune diseases affecting primarily the joints. Despite successful therapies including antibodies against tumor necrosis factor (TNF) and interleukin-6 (IL-6) receptor, only 20 to 30% of patients experience remission. We studied whether inhibiting both TNF and IL-6 would result in improved efficacy. Using backtranslation from single-cell RNA sequencing (scRNA-seq) data from individuals with RA, we hypothesized that TNF and IL-6 act synergistically on fibroblast-like synoviocytes (FLS) and T cells. Coculture of FLS from individuals with RA and T cells supported this hypothesis, revealing effects on both disease-driving pathways and biomarkers. Combining anti-TNF and anti-IL-6 antibodies in collagen-induced arthritis (CIA) mouse models resulted in sustained long-term remission, improved histology, and effects on bone remodeling pathways. These promising data initiated the development of an anti-TNF/IL-6 bispecific nanobody compound 1, with similar potencies against TNF and IL-6. We observed additive efficacy of compound 1 in a FLS/T cell coculture affecting arthritis and T helper 17 (TH17) pathways. This nanobody compound transcript signature inversely overlapped with described RA endotypes, indicating a potential efficacy in a broader patient population. In summary, we showed superiority of a bispecific anti-TNF/IL-6 nanobody compound or combination treatment over monospecific treatments in both in vitro and in vivo models. We anticipate improved efficacy in upcoming clinical studies.

TNF or EGFR inhibition equally block AKI-to-CKD transition: opportunities for etanercept treatment.

BACKGROUND: Inflammation is a key driver of the transition of acute kidney injury to progressive fibrosis and chronic kidney disease (AKI-to-CKD transition). Blocking a-disintegrin-and-metalloprotease-17 (ADAM17)-dependent ectodomain shedding, in particular of epidermal growth factor receptor (EGFR) ligands and of the type 1 inflammatory cytokine tumor necrosis factor (TNF), reduces pro-inflammatory and pro-fibrotic responses after ischemic AKI or unilateral ureteral obstruction (UUO), a classical fibrosis model. Metalloprotease or EGFR inhibition show significant undesirable side effects in humans. In retrospective studies anti-TNF biologics reduce the incidence and progression of CKD in humans. Whether TNF has a role in AKI-to-CKD transition and how TNF inhibition compares to EGFR inhibition is largely unknown. METHODS: Mice were subjected to bilateral renal ischemia-reperfusion injury or unilateral ureteral obstruction. Kidneys were analyzed by histology, immunohistochemistry, qPCR, western blot, mass cytometry, scRNA sequencing, and cytokine profiling. RESULTS: Here we show that TNF or EGFR inhibition reduce AKI-to-CKD transition and fibrosis equally by about 25%, while combination has no additional effect. EGFR inhibition reduced kidney TNF expression by about 50% largely by reducing accumulation of TNF expressing immune cells in the kidney early after AKI, while TNF inhibition did not affect EGFR activation or immune cell accumulation. Using scRNAseq data we show that TNF is predominantly expressed by immune cells in AKI but not in proximal tubule cells (PTC), and PTC-TNF knockout did not affect AKI-to-CKD transition in UUO. Thus, the anti-inflammatory and anti-fibrotic effects of the anti-TNF biologic etanercept in AKI-to-CKD transition rely on blocking TNF that is released from immune cells recruited or accumulating in response to PTC-EGFR signals. CONCLUSION: Short-term anti-TNF biologics during or after AKI could be helpful in the prevention of AKI-to-CKD transition.

TNF-α inhibitor ameliorates immune-related arthritis and pneumonitis in humanized mice.

Objectives: This study aimed at establishing a mouse model of immune-related adverse in humanized BALB/c-hPD1/hCTLA4 mice to investigate their potential pathogenesis and explore therapeutic targets for immune-related arthritis and pneumonitis. Methods: Humanized BALB/c-hPD1/hCTLA4 mice were injected with vehicle or collagen-specific antibodies (CA) and immune checkpoint inhibitors (ICI, ipilimumab, anti-human CTLA-4; and nivolumab, anti-human PD-1), and some mice were treated with anti-TNF-α antibody, leading to the control, collagen antibody-induced arthritis (CAIA), CAIA+ICI and treatment groups. The severity of clinical arthritis and pneumonitis in mice was monitored longitudinally and the pathological changes in the joints and lungs were histologically analyzed and the contents of lung hydroxyproline were measured. The frequency of different subsets of T cells was analyzed by flow cytometry and multiplex immunofluorescency. Results: Compared with the control, the ICI group of mice developed the delayed onset of moderate degrees of arthritis while the CAIA+ICI group of mice exhibited the early onset of severe arthritis. Treatment with ICI caused severe pneumonitis, especially in the mice with CA. Flow cytometry analysis indicated a significantly higher frequency of splenic TNF-α+CD4+ and TNF-α+CD8+ T cells, but not other subsets of T cells tested, in the CAIA+ICI group of mice, relative to that in other groups of mice. Treatment with anti-TNF-α significantly mitigated the severity of arthritis and pneumonitis as well as deposition of collagen in lung of mice. The treatment also decreased the frequency of TNF-α+CD4+ and TNF-α+CD8+ T cells as well as effector memory T cells in the periphery lymph orangs and lungs of mice. Conclusions: We successfully established a humanized mouse model of ICI-related severe arthritis and pneumonitis with a higher frequency of TNF-α+ T cells, which were significantly mitigated by anti-TNF-α treatment. Conceptually, ICI treatment can induce multiple autoimmune-like diseases in autoimmune-prone individuals and TNF-α+ T cells may be therapeutic targets for intervention of immune-related arthritis and pneumonitis.

Persistent popliteal lymphatic muscle cell coverage defects despite amelioration of arthritis and recovery of popliteal lymphatic vessel function in TNF-Tg mice following anti-TNF therapy.

While rheumatoid arthritis patients and tumor necrosis factor transgenic (TNF-Tg) mice with inflammatory-erosive arthritis display lymphatic drainage deficits, the mechanisms responsible remain unknown. As ultrastructural studies of joint-draining popliteal lymphatic vessels (PLVs) in TNF-Tg mice revealed evidence of lymphatic muscle cell (LMC) damage, we aimed to evaluate PLV-LMC coverage in TNF-Tg mice. We tested the hypothesis that alpha smooth muscle actin (αSMA)+ PLV-LMC coverage decreases with severe inflammatory-erosive arthritis, and is recovered by anti-TNF therapy facilitated by increased PLV-LMC turnover during amelioration of joint disease. TNF-Tg mice with established disease received anti-TNF monoclonal antibody (mAb) or placebo IgG isotype control mAb therapy (n = 5) for 6-weeks, while wild-type (WT) littermates (n = 8) received vehicle (PBS). Bromodeoxyuridine (BrdU) was also administered daily during the treatment period to monitor PLV-LMC turnover. Effective anti-TNF therapy was confirmed by longitudinal assessment of popliteal lymph node (PLN) volume via ultrasound, PLV contraction frequency via near-infrared imaging of indocyanine green, and ankle bone volumes via micro-computed tomography (micro-CT). Terminal knee micro-CT, and ankle and knee histology were also performed. PLVs were immunostained for αSMA and BrdU to evaluate PLV-LMC coverage and turnover, respectively, via whole-mount fluorescent microscopy. Anti-TNF therapy reduced PLN volume, increased talus and patella bone volumes, and reduced tarsal and knee synovial areas compared to placebo treated TNF-Tg mice (p < 0.05), as expected. Anti-TNF therapy also increased PLV contraction frequency at 3-weeks (from 0.81 ± 1.0 to 3.2 ± 2.0 contractions per minute, p < 0.05). However, both anti-TNF and placebo treated TNF-Tg mice exhibited significantly reduced αSMA+ PLV-LMC coverage compared to WT (p < 0.05). There was no correlation of αSMA+ PLV-LMC coverage restoration with amelioration of inflammatory-erosive arthritis. Similarly, there was no difference in PLV-LMC turnover measured by BrdU labeling between WT, TNF-Tg placebo, and TNF-Tg anti-TNF groups with an average of < 1% BrdU+ PLV-LMCs incorporated per week. Taken together these results demonstrate that PLV-LMC turnover in adult mice is limited, and that recovery of PLV function during amelioration of inflammatory-erosive arthritis occurs without restoration of αSMA+ LMC coverage. Future studies are warranted to investigate the direct and indirect effects of chronic TNF exposure, and the role of proximal inflammatory cells on PLV contractility.

Effects of Etanercept on TNF-α Inhibition in Rats with Adenine-Induced Chronic Kidney Disease.

Introduction: Chronic kidney disease (CKD) constitutes a chronic inflammatory state associated with an increase in inflammatory mediators and profibrotic molecules such as tumor necrosis factor-α (TNF-α). Etanercept (ETA) is a TNF inhibitor widely used in treatment of autoimmune inflammatory diseases. However, the effects of TNF-α inhibition in the establishment of CKD have not been fully elucidated. We evaluate the effects of TNF inhibition by ETA in adenine- (Ad-) induced CKD in rats. Methods: Rats were divided into three groups: control, renal injury model, and model plus ETA (2 mg/kg, 3 times per week (w); sc). Renal injury was induced by Ad administration (100 mg/kg, daily for 2 or 4 w; orogastric). Serum TNF-α levels and biochemical parameters for renal function were evaluated. Histopathological changes in the kidney were assessed using H&E and Masson's trichrome staining and also immunostaining for tubular cells. Results: Ad administration produced a renal functional decline, tubular atrophy, interstitial inflammation, and fibrosis for 2 w, followed by renal anemia, several renal dysfunctions, tubular atrophy, and fibrosis at 4 w. A significant increase in serum TNF-α levels was observed from 2 w of Ad administration and remained elevated up to 4 w. Treatment with ETA partially reduced kidney damage but was very effective to blocking serum TNF-α. Conclusion: Although inhibition of TNF by ETA was very effective in reducing serum TNF-α, this strategy was partially effective in preventing Ad-induced CKD.

Characterization and Validation of In Vitro and In Vivo Models to Investigate TNF-α-Induced Inflammation in Retinal Diseases.

Purpose: Inflammation is implicated in the etiology of diverse retinopathies including uveitis, age-related macular degeneration or diabetic retinopathy. Tumor necrosis factor alpha (TNF-α) is a well-known proinflammatory cytokine that is described as a biomarker for inflammation in diverse retinopathies and therefore emerged as an interesting target to treat inflammation in the eye by neutralizing anti-TNF-α antibodies. Methods: Recently, we have demonstrated that Adeno-associated virus (AAV)-mediated expression of human TNF-α in the murine eye induces retinal inflammation including vasculitis and fibrosis, thereby mimicking human disease-relevant pathologies. In a proof-of-mechanism study, we now tested whether AAV-TNF-α induced pathologies can be reversed by neutralizing TNF-α antibody treatment. Results: Strikingly, a single intravitreal injection of the TNF-α antibody golimumab reduced AAV-TNF-α-induced retinal inflammation and retinal thickening. Furthermore, AAV-TNF-α-mediated impaired retinal function was partially rescued by golimumab as revealed by electroretinography recordings. Finally, to study TNF-α-induced vasculitis in human in vitro cell culture assays, we established a monocyte-to-endothelium adhesion co-culture system. Indeed, also in vitro TNF-α induced monocyte adhesion to human retinal endothelial cells, which was prevented by golimumab. Conclusions: Overall, our study describes valuable in vitro and in vivo approaches to study the function of TNF-α in retinal inflammation and demonstrated a preclinical proof-of-mechanism treatment with golimumab. Translational Relevance: The AAV-based model expressing human TNF-α allows us to investigate TNF-α-driven pathologies supporting research in mechanisms of retinal inflammation.