Discovery of the TLR7/8 Antagonist MHV370 for Treatment of Systemic Autoimmune Diseases

Toll-like receptor (TLR) 7 and TLR8 are endosomal sensors of the innate immune system that are activated by GU-rich single stranded RNA (ssRNA). Multiple genetic and functional lines of evidence link chronic activation of TLR7/8 to the pathogenesis of systemic autoimmune diseases (sAID) such as Sjögren's syndrome (SjS) and systemic lupus erythematosus (SLE). This makes targeting TLR7/8-induced inflammation with small-molecule inhibitors an attractive approach for the treatment of patients suffering from systemic autoimmune diseases. Here, we describe how structure-based optimization of compound 2 resulted in the discovery of 34 (MHV370, (S)-N-(4-((5-(1,6-dimethyl-1H-pyrazolo[3,4-b]pyridin-4-yl)-3-methyl-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridin-1-yl)methyl)bicyclo[2.2.2]octan-1-yl)morpholine-3-carboxamide). Its in vivo activity allows for further profiling toward clinical trials in patients with autoimmune disorders, and a Phase 2 proof of concept study of MHV370 has been initiated, testing its safety and efficacy in patients with Sjögren's syndrome and mixed connective tissue disease.

VRE acquisition in hospital and its association with hospital antimicrobial usage -a non-linear analysis of an extended time series

BACKGROUND

Vancomycin resistant enterococci (VRE) have become endemic pathogens in many Australian hospitals causing significant morbidity. There are few observational studies that have evaluated the effect of antibiotic usage on VRE acquisition. This study examined VRE acquisition and its association with antimicrobial use. The setting was a NSW tertiary hospital with 800 beds over a 63 month period up to March 2020, straddling piperacillin-tazobactam (PT) shortages that occurred from in September 2017.

METHODS

The primary outcome was monthly inpatient hospital onset Vancomycin-resistant Enterococci (VRE) acquisitions. Multivariate adaptive regression splines (MARS) were used to estimate hypothetical thresholds, where antimicrobial use above threshold is associated with increased incidence of hospital onset VRE acquisition. Specific antimicrobials and categorised usage (broad, less broad and narrow spectrum) were modelled.

RESULTS

There were 846 hospital onset VRE detections over the study period. Hospital onset vanB and vanA VRE acquisitions fell significantly by 64% and 36% respectively after the PT shortage. MARS modelling indicated that PT usage was the only antibiotic found to exhibit a meaningful threshold. PT usage greater than 17.4 defined daily doses/1000 occupied bed-days (95%C I: 13.4, 20.5) was associated with higher onset of hospital VRE.

CONCLUSIONS

This paper highlights the large, sustained impact that reduced broad spectrum antimicrobial use had on VRE acquisition and showed that PT use in particular was a major driver with a relatively low threshold. It raises the question as to whether hospitals should be determining local antimicrobial usage targets based on direct evidence from local data analysed with non-linear methods.

Preclinical characterization of the Toll-like receptor 7/8 antagonist MHV370 for lupus therapy

Genetic and in vivo evidence suggests that aberrant recognition of RNA-containing autoantigens by Toll-like receptors (TLRs) 7 and 8 drives autoimmune diseases. Here we report on the preclinical characterization of MHV370, a selective oral TLR7/8 inhibitor. In vitro, MHV370 inhibits TLR7/8-dependent production of cytokines in human and mouse cells, notably interferon-α, a clinically validated driver of autoimmune diseases. Moreover, MHV370 abrogates B cell, plasmacytoid dendritic cell, monocyte, and neutrophil responses downstream of TLR7/8. In vivo, prophylactic or therapeutic administration of MHV370 blocks secretion of TLR7 responses, including cytokine secretion, B cell activation, and gene expression of, e.g., interferon-stimulated genes. In the NZB/W F1 mouse model of lupus, MHV370 halts disease. Unlike hydroxychloroquine, MHV370 potently blocks interferon responses triggered by specific immune complexes from systemic lupus erythematosus patient sera, suggesting differentiation from clinical standard of care. These data support advancement of MHV370 to an ongoing phase 2 clinical trial.

Modulation, microbiota and inflammation in the adult CF gut: A prospective study

BACKGROUND

Cystic Fibrosis (CF) has prominent gastrointestinal and pancreatic manifestations. The aim of this study was to determine the effect of Cystic fibrosis transmembrane conductance regulator (CFTR) modulation on, gastrointestinal inflammation, pancreatic function and gut microbiota composition in people with cystic fibrosis (CF) and the G551D-CFTR mutation.

METHODS

Fourteen adult patients with the G551D-CFTR mutation were assessed clinically at baseline and for up to 1 year after treatment with ivacaftor. The change in gut inflammatory markers (calprotectin and lactoferrin), exocrine pancreatic status and gut microbiota composition and structure were assessed in stool samples.

RESULTS

There was no significant change in faecal calprotectin nor lactoferrin in patients with treatment while all patients remained severely pancreatic insufficient. There was no significant change in gut microbiota diversity and richness following treatment.

CONCLUSION

There was no significant change in gut inflammation after partial restoration of CFTR function with ivacaftor, suggesting that excess gut inflammation in CF is multi-factorial in aetiology. In this adult cohort, exocrine pancreatic function was irreversibly lost. Longer term follow-up may reveal more dynamic changes in the gut microbiota and possible restoration of CFTR function.

How accurately is hospital acquired pneumonia documented for the correct assignment of a hospital acquired complication (HAC)?

BACKGROUND

In 2016, the Australian Commission on Safety and Quality in Healthcare (ACSQHC) released a list of 16 categories of potentially preventable, high impact hospital-acquired complications (HAC) identified by using administrative coded data (ACD). An important category are hospital-acquired infections (HAI). Within this category, hospital-acquired pneumonia (HAP) is among the most frequent complications documented. There are no published studies concerning the current ACSQHC approach to HAI surveillance using ACD and no pneumonia-specific ACD studies reported from Australia. Published work indicates that ACD detection of HAP has low a sensitivity and positive predictive value (PPV). The current study was designed to examine whether coders correctly reflected the documentation of HAP that was present in the medical record and also evaluated the medical documentation that was present.

METHODS

One hundred patients with ACD encoded HAP were selected for review, drawn from admissions to 2 Hunter New England Health hospitals during 2017. Patient records and the eMR were reviewed by two medical officers to assess medical and radiological documentation of pneumonia. The district coding manager reviewed the accuracy of coding of a subset of 23 cases where medical review had not located documented evidence of HAP.

RESULTS

Of the 100 reviewed cases, the median patient age was 75 years (range 0-95 years) with 3% under 16 years of age. Twenty one were intensive care-associated of which 13 were associated with ventilation. In 23 cases the documentation was disputed and a secondary review took place - the coding manager confirmed coding changes in 14 of these 23 cases.

CONCLUSIONS

This study found that administrative coded data of HAP, utilizing the ACSQHC method reliably reflected the available documentation with a PPV of 86% (95% binomial exact confidence interval 77-92%), much higher than documented by previous ACD studies. The actual documentation of pneumonia by medical staff frequently used the non-specific term 'lower respiratory infection (LRTI)' which we recommend to be avoided. Radiological confirmation was absent in one third of cases. We recommend the adoption of a medical note template checklist for HAP to prompt clinicians with the accepted diagnostic criteria. We also recommend documenting a reason as to why any antibiotic has been commenced in a hospitalized patient in accord with the ACSQHC Antimicrobial Stewardship Clinical Care Standard.

Target-Based Identification and Optimization of 5-Indazol-5-yl Pyridones as Toll-like Receptor 7 and 8 Antagonists Using a Biochemical TLR8 Antagonist Competition Assay

Inappropriate activation of endosomal TLR7 and TLR8 occurs in several autoimmune diseases, in particular systemic lupus erythematosus (SLE). Herein, the development of a TLR8 antagonist competition assay and its application for hit generation of dual TLR7/8 antagonists are reported. The structure-guided optimization of the pyridone hit 3 using this biochemical assay in combination with cellular and TLR8 cocrystal structural data resulted in the identification of a highly potent and selective TLR7/8 antagonist (27) with in vivo efficacy. The two key steps for optimization were (i) a core morph guided by a TLR7 sequence alignment to achieve a dual TLR7/8 antagonism profile and (ii) introduction of a fluorine in the piperidine ring to reduce its basicity, resulting in attractive oral pharmacokinetic (PK) properties and improved TLR8 binding affinity.

VSV-primed CD8+ T cells suppress autoreactive germinal centers

Pathogenic infections are important environmental modifiers of autoimmune disease as they can alter the immune system in a way that either promotes or reduces autoimmune responses. We tested the effect of infection with vesicular stomatitis virus (VSV) on the FcγR2B−/− (R2) mouse strain that spontaneously develops lupus disease. Infecting FcγR2B−/− mice with live VSV reduces autoantibody levels and inflammatory pathology and prolongs survival. We showed that VSV-mediated protection can be transferred in a CD8 cell adoptive transfer experiment. After further testing the transfer of various CD8 T cell subsets, we have identified CD8+CD122+NKG2D+ cells as mediator in VSV-induced Lupus amelioration. RNA Sequencing data for gene expression profiles among various CD8 subsets, indicate that the protective cells express higher level of genes linked to memory phenotype. Our working hypothesis is that the viral infection may induce the expansion of long lived CD8 populations that regulate the antibody response.

In support of the idea we initiated to identify the target of the VSV-primed CD8 T cells in vivo. We examined the effect of VSV-primed CD8 T cells on the immune phenotypes of recipient R2 mice at the initial stages, e.g. after 1, 2 or 3 weeks of transfer. Interestingly, we found that Tfh and germinal center B cells are significantly reduced after three weeks of VSV-CD8 transfer. Thus, the protective CD8 T cells from VSV-infected mice might target autoreactive germinal center to regulate the antibody response. How VSV-CD8 T cells might control germinal center & why it takes about 3 weeks for controlling is under investigation.

Lupus-suppressing effect of VSV-primed CD8+ T cell subsets

Pathogenic infections are important environmental modifiers of autoimmune disease as they can alter the immune system in a way that either promotes or reduces autoimmune responses. We tested the effect of infection with vesicular stomatitis virus (VSV) on the FcγR2B−/− (R2) mouse strain that spontaneously develops lupus disease. Infecting FcγR2B−/− mice with live VSV reduces autoantibody levels and inflammatory pathology, and prolongs survival. We showed that VSV-mediated protection can be transferred in a CD8 cell adoptive transfer experiment. Legend screening for surface markers on CD8 T cells indicated that CD8 T cells from VSV infected mice express high level of markers linked to exhausted and regulatory phenotypes. After testing the transfer of various CD8 T cell subsets, we have identified CD8+CD122+NKG2D+ cells as mediator in VSV-induced Lupus amelioration. Preliminary analysis of RNA Sequencing data for gene expression profiles among various CD8 subsets, indicate that the protective cells express higher level of genes linked to memory phenotype. Our working hypothesis is that the viral infection may induce the expansion of long lived CD8 populations that regulate the humoral response.

A survey to determine usual care after cancer treatment within the United Kingdom national health service

BACKGROUND

Approximately one third of cancer survivors in the United Kingdom face ongoing and debilitating psychological and physical symptoms related to poor quality of life. Very little is known about current post-cancer treatment services.

METHODS

Oncology healthcare professionals (HCPs) were invited to take part in a survey, which gathered both quantitative and free text data about the content and delivery of cancer aftercare and patient needs. Analysis involved descriptive statistics and content analysis.

RESULTS

There were 163 complete responses from 278 survey participants; 70% of NHS acute trusts provided data. HCPs views on patient post-cancer treatment needs were most frequently: fear of recurrence (95%), fatigue (94%), changes in physical capabilities (89%), anxiety (89%) and depression (88%). A median number of 2 aftercare sessions were provided (interquartile range: 1,4) lasting between 30 and 60 min. Usually these were provided face-to-face and intermittently by a HCP. However, sessions did not necessarily address the issues HCPs asserted as important. Themes from free-text responses highlighted inconsistencies in care, uncertain funding for services and omission of some evidence based approaches.

CONCLUSION

Provision of post-cancer treatment follow-up care is neither universal nor consistent in the NHS, nor does it address needs HCPs identified as most important.

Mesenchymal stem/stromal cells in post-menopausal endometrium

STUDY QUESTION

Does post-menopausal endometrium contain mesenchymal stem/stromal cells (MSC) that have adult stem cell properties and can be prospectively isolated from a biopsy?

SUMMARY ANSWER

Perivascular W5C5(+) cells isolated from post-menopausal endometrial biopsies displayed characteristic MSC properties of clonogenicity, multipotency and surface phenotype irrespective of whether the women were or were not pre-treated with estrogen to regenerate the endometrium.

WHAT IS KNOWN ALREADY

Recently MSCs have been identified in human premenopausal endometrium, and can be prospectively isolated using a single marker, W5C5/SUSD2.

STUDY DESIGN, SIZE, DURATION

Endometrial tissue of both the functional and basal layers, from 17 premenopausal (pre-MP) women, 19 post-menopausal (post-MP) women without hormonal treatment and 15 post-menopausal women on estrogen replacement therapy (post-MP+ E2), was collected through a prospective phase IV clinical trial over 2 years.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Post-menopausal women <65 years of age were treated with or without E2 for 6-8 weeks prior to tissue collection. Serum E2 levels were determined by estradiol immunoenzymatic assay. Endometrial tissue was obtained from women by biopsy (curettage) just prior to the hysterectomy. The effect of E2 on endometrial thickness and glandular and luminal epithelial height was determined using image analysis. Endometrial tissue was dissociated into single cell suspensions and MSC properties were examined in freshly isolated and short-term cultured, magnetic bead-purified W5C5(+) cells. MSC properties were assessed using clonogenicity, serial cloning, mesodermal differentiation in adipogenic, chondrogenic, osteogenic and myogenic induction culture media, and surface phenotype analysis by flow cytometry. Estrogen receptor α expression in W5C5(+) cells was examined using dual colour immunofluorescence. Vascularity was analysed using CD34 and alpha smooth muscle actin immunostaining and subsequent image analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

A small population of stromal cells with MSC properties was purified with the W5C5 antibody from post-menopausal endometrium, whether atrophic from low circulating estrogen or regenerated from systemic estrogen treatment, similar to premenopausal endometrium. The MSC derived from post-menopausal endometrium treated with or without E2 fulfilled the minimum MSC criteria: clonogenicity, surface phenotype (CD29(+), CD44(+), CD73(+), CD105(+), CD140b(+), CD146(+)) and multipotency. The post-menopausal endometrial MSCs also showed comparable properties to premenopausal eMSC with respect to self-renewal in vitro and W5C5 expression. The W5C5(+) cells were located perivascularly as expected and did not express estrogen receptor α.

LIMITATIONS, REASONS FOR CAUTION

The properties of the MSC derived from post-menopausal endometrium were evaluated in vitro and their in vivo tissue reconstitution capacity has not been established as it has for premenopausal endometrial MSC.

WIDER IMPLICATIONS OF THE FINDINGS

The endometrium is an accessible source of MSC obtainable with minimum morbidity that could be used for future clinical applications as a cell-based therapy. This study shows that menopausal women can access their endometrial MSC by a simple biopsy for use in autologous therapies, particularly if their endometrium has been regenerated by short-term E2 treatment, provided they have an intact uterus and are not contraindicated for short-term E2 treatment. Endometrial MSC in post-menopausal women possess key MSC properties and are a promising source of MSC independent of a woman's age.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by the National Health and Medical Research Council (NHMRC) of Australia grant (1021126) (C.E.G., A.R.) and Senior Research Fellowship (1042298) (C.E.G.), Australian Gynaecological Endoscopic Society grant (A.R.) , Monash International Postgraduate Research Scholarship (DU), Australian Stem Cell Centre, South East Melbourne Alliance for Regenerative Therapies and Australian Stem Cell Centre top up scholarships (DU) and Victorian Government's Operational Infrastructure Support Program. Competing interests: AR receives Preceptorship fees from AMS, advisory board fees and sponsored study from Astellas, and conducts investigator led studies sponsored by AMS and Boston Scientific for other projects.

TRIAL REGISTRATION NUMBER

CTNRN12610000563066.

Bilateral rubeosis iridis and rubeotic glaucoma due to peripheral occlusive vasculitis associated with multiple sclerosis

Multiple sclerosis is associated with iridocyclitis, intermediate uveitis, retinal periphlebitis, and optic neuritis. The periphlebitis is known to be rarely sight-threatening as a result of the sequelae of retinal neovascularization.

CASE

This is a rare case of bilateral rubeosis iridis and rubeotic glaucoma in the setting of a branch retinal vein occlusion, widespread peripheral periphlebitis, and angiographic peripheral closure associated with "clinically definite" multiple sclerosis.

DISCUSSION

The case illustrates the extreme end of the spectrum of peripheral retinal ischemia and neovascularization associated with demyelinating disease, which can present as rubeotic glaucoma. Such patients require a proactive approach to inflammation, neovascularization, and raised intraocular pressure, including systemic immunosuppression, photocoagulation, and augmented trabeculectomy, respectively. As with other causes of peripheral ischemia, a favorable visual outcome can often be achieved using this strategy.

VSV infection ameliorates autoimmune disease in FcγR2B deficient mice (101.14)

We have investigated whether infection by pathogens affects the development of autoimmune diseases such as lupus. We tested the effect of infection with vesicular stomatitis virus (VSV) on two mouse strains that spontaneously develop lupus disease. Infection of VSV in lupus prone FcγR2B-/- (R2) mice significantly reduced autoantibody titers and inflammatory cytokines and chemokines in serum, reduced glomerulonephritis, and improved survival. In contrast, VSV infection in R2yaa mice, which develop a more aggressive lupus disease, showed slightly reduced auto-antibody titers in the serum without any major changes in serum cytokines and chemokines, kidney glomreulonephritis, or survival. Characterization of immune cell phenotypes in VSV infected R2 mice showed that B cell development in the bone marrow was not affected whereas germinal center, plasma, and IgG producing mature B cell numbers were reduced. Additionally, VSV infected R2 mice had lower number of follicular helper T cells and CD11c+ cells in the spleen. Compared to uninfected mice, microarray analysis of naïve resting B cells from VSV infected R2 splenocytes showed up-regulation of several candidate genes including a non receptor type protein tyrosine phosphatase, PTPN22 that has been shown to be associated with Lupus and other autoimmune diseases. Studies of the functional implications of Ptpn22 overexpression in VSV-infected R2 B cells are in progress.

Transgenic expression of MDA5 enhances interferon responses, CD8 activation, and viral clearance (110.19)

MDA5 is a pattern recognition receptor responsible for detecting double stranded viral RNA in the cytoplasm. Ligation of MDA5 leads to the induction of inflammatory cytokines and type one interferons (IFN-I) that help coordinate the adaptive and innate immune response against the virus. Here, we describe the phenotype of mice overexpressing MDA5 under its endogenous promoter. MDA5 transgenic (MDA5 Tg) mice have normal numbers of B and T cells, yet expanded numbers of CD11b+ cells expressing Ly6C. Splenocytes isolated from MDA5 Tg display an interferon gene expression signature. MDA5 Tg CD8+ T cells have increased surface expression of CD44, CD69, Ly6C and Ly6A/E, indicative of an activated phenotype. In vitro, CD8+ T cells from MDA5 tg hyperrespond to stimulation. Surprisingly, MDA5 tg mice fail to mount a CD8+ T cell-driven antigen-specific immune response against Vesicular stomatitis virus (VSV). MDA5 tg mice also lacked VSV neutralizing antibodies 16 days after infection with the virus. Although MDA5 tg mice failed to mount a full immune response against the virus, they were resistant to a lethal dose of VSV. This result suggests that increased viral resistance of MDA5 Tg is independent of antibody-neutralization and CD8+ T cell-mediated clearance, and might be due to high expression levels of interferon inducible inhibitors of virus replication. MDA5 tg mice could serve as a model for diseases involving type one interferon and CD8+ T cells, such as Type One Diabetes.

Transgenic Expression of the RNA-sensing Molecule MDA-5 Accelerates Autoimmunity in the Lupus-prone FcgammaR2-Deficient Mouse (93.20)

Nucleic-acid sensing molecules provide a first line of defense against microbial infections, but recent studies have shown that their inappropriate activation could promote autoimmunity. MDA-5 senses virally-derived RNA in the cytoplasm, which leads to type one interferon (IFN) production, recently shown to be associated with systemic lupus erythematosus. Here, we have generated mice with multiple copies of Ifih1, the gene that encodes MDA-5, and crossed them to the lupus-prone FcgammaRIIB-/- mouse. Mice with enhanced MDA-5 expression and FcgammaRIIB deficiency have accelerated autoimmunity with splenomegaly and anti-nuclear antibodies in their serum compared to FcgammaRIIB-deficient mice alone. They also display elevated levels of splenic plasma and germinal center B cells, indicating possible early autoreactive B cell formation. Bone marrow and splenic macrophage/monocytes from MDA5 transgenic animals also display an activated phenotype, characterized by elevated Ly6A/E, PDCA-1 and CD80 expression. B cells from MDA-5-transgenic animals also express elevated levels of type one IFN signature genes. These results suggest that increased expression of MDA-5 could exacerbate lupus, possibly through the early production of type one IFN.

Unraveling the realities of vascular access: the Network 11 experience

Arteriovenous (AV) fistulae are well recognized as the preferred vascular access for hemodialysis, yet national data show that only 23% of patients used an AV fistula in 1997. To identify barriers to the placement of native AV fistulae, the Renal Network of the Upper Midwest, Inc. (End-Stage Renal Disease [ESRD] Network 11) initiated a vascular access project to look at the process of referral for patients beginning hemodialysis in the first 6 months of 1999. Of these patients, 63% began hemodialysis with a catheter as the only access, 22% had an AV fistula placed (but only 14% used an AV fistula for their first dialysis treatment), and 15% began with a graft. About 40% of patients were referred to a nephrologist less than 1 month before dialysis, allowing little chance for permanent access placement. Yet 27% of patients used a catheter on the first hemodialysis treatment and were seen by a nephrologist more than 1 month before starting dialysis, indicating the presence of an opportunity to improve. At 6 months after initiation of dialysis, 25% of patients who began dialysis using a catheter were using an AV fistula and 35% were using a graft. Network 11 plans to use this information to promote early referral of patients to a nephrologist and subsequent prompt referral of such patients to a vascular surgeon. Other activities to improve vascular access management are also indicated.

The Internet and poverty: real help or real hype? Panos Briefing No. 28

Governments, donors and development organisations are rushing to realise the benefits that Internet access promises in the fight against poverty. But are the benefits it has brought so far merely isolated examples or are they signs that a revolution is underway? Access to information is an essential condition of development. The Internet has prompted a change in development thinking and many donor and multilateral lending organisations are radically reshaping their policies for the new information age. But is the enthusiasm among donors for spending on Internet development diverting funds from more traditional forms of development assistance? In terms of its most adaptive component, the World Wide Web, the Internet is still only four years old. Real hype or real help? The jury is still out. Quite simply, it is still too soon to tell.

In situ degradation of 11/0 polyester (mersilene) suture material following cataract surgery

Two hundred and ten patients (231 eyes) had their cataract sections closed with 11/0 polyester suture material over a 4 year period. Their case sheets were assessed to determine the number of eyes from which sutures had been removed prior to discharge, and for what reasons these sutures were removed. Ninety-seven patients (107 eyes) with sutures left in situ were further assessed to determine whether they were suffering from any suture-related symptoms and examined to determine the degree of clinical biodegradation experienced by the sutures. Six of these sutures were removed for electron microscopic examination. Of the 231 eyes initially included, 61 sutures (26.4%) had been removed prior to discharge. None of the 107 sutures examined showed evidence of clinical biodegradation; this was confirmed by electron microscopic analysis which showed only minimal erosion of sutures even after 48 months in situ.