Treating Autoimmune Diseases With LANCL2 Therapeutics: A Novel Immunoregulatory Mechanism for Patients With Ulcerative Colitis and Crohn's Disease

Lanthionine synthetase C-like 2 (LANCL2) therapeutics have gained increasing recognition as a novel treatment modality for a wide range of autoimmune diseases. Genetic ablation of LANCL2 in mice results in severe inflammatory phenotypes in inflammatory bowel disease (IBD) and lupus. Pharmacological activation of LANCL2 provides therapeutic efficacy in mouse models of intestinal inflammation, systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, and psoriasis. Mechanistically, LANCL2 activation enhances regulatory CD4 + T cell (Treg) responses and downregulates effector responses in the gut. The stability and suppressive capacities of Treg cells are enhanced by LANCL2 activation through engagement of immunoregulatory mechanisms that favor mitochondrial metabolism and amplify IL-2/CD25 signaling. Omilancor, the most advanced LANCL2 immunoregulatory therapeutic in late-stage clinical development, is a phase 3 ready, first-in-class, gut-restricted, oral, once-daily, small-molecule therapeutic in clinical development for the treatment of UC and CD. In this review, we discuss this novel mechanism of mucosal immunoregulation and how LANCL2-targeting therapeutics could help address the unmet clinical needs of patients with autoimmune diseases, starting with IBD.

Oral Omilancor Treatment Ameliorates Clostridioides difficile Infection During IBD Through Novel Immunoregulatory Mechanisms Mediated by LANCL2 Activation

BACKGROUND

Clostridioides difficile infection (CDI) is an opportunistic infection of the gastrointestinal tract, commonly associated with antibiotic administration, that afflicts almost 500 000 people yearly only in the United States. CDI incidence and recurrence is increased in inflammatory bowel disease (IBD) patients. Omilancor is an oral, once daily, first-in-class, gut-restricted, immunoregulatory therapeutic in clinical development for the treatment of IBD.

METHODS

Acute and recurrent murine models of CDI and the dextran sulfate sodium-induced concomitant model of IBD and CDI were utilized to determine the therapeutic efficacy of oral omilancor. To evaluate the protective effects against C. difficile toxins, in vitro studies with T84 cells were also conducted. 16S sequencing was employed to characterize microbiome composition.

RESULTS

Activation of the LANCL2 pathway by oral omilancor and its downstream host immunoregulatory changes decreased disease severity and inflammation in the acute and recurrence models of CDI and the concomitant model of IBD/CDI. Immunologically, omilancor treatment increased mucosal regulatory T cell and decreased pathogenic T helper 17 cell responses. These immunological changes resulted in increased abundance and diversity of tolerogenic gut commensal bacterial strains in omilancor-treated mice. Oral omilancor also resulted in accelerated C. difficile clearance in an antimicrobial-free manner. Furthermore, omilancor provided protection from toxin damage, while preventing the metabolic burst observed in intoxicated epithelial cells.

CONCLUSIONS

These data support the development of omilancor as a novel host-targeted, antimicrobial-free immunoregulatory therapeutic for the treatment of IBD patients with C. difficile-associated disease and pathology with the potential to address the unmet clinical needs of ulcerative colitis and Crohn's disease patients with concomitant CDI.

Modulation of colonic immunometabolic responses during Clostridioides difficile infection ameliorates disease severity and inflammation

Clostridioides difficile infection (CDI) is the leading cause of antibiotic-associated diarrhea, and its clinical symptoms can span from asymptomatic colonization to pseudomembranous colitis and even death. The current standard of care for CDI is antibiotic treatment to achieve bacterial clearance; however, 15 to 35% of patients experience recurrence after initial response to antibiotics. We have conducted a comprehensive, global colonic transcriptomics analysis of a 10-day study in mice to provide new insights on the local host response during CDI and identify novel host metabolic mechanisms with therapeutic potential. The analysis indicates major alterations of colonic gene expression kinetics at the acute infection stage, that are restored during the recovery phase. At the metabolic level, we observe a biphasic response pattern characterized by upregulated glycolytic metabolism during the peak of inflammation, while mitochondrial metabolism predominates during the recovery/healing stage. Inhibition of glycolysis via 2-Deoxy-D-glucose (2-DG) administration during CDI decreases disease severity, protects from mortality, and ameliorates colitis in vivo. Additionally, 2-DG also protects intestinal epithelial cells from C. difficile toxin damage, preventing loss of barrier integrity and secretion of proinflammatory mediators. These data postulate the pharmacological targeting of host immunometabolic pathways as novel treatment modalities for CDI.

Computational modeling of complex bioenergetic mechanisms that modulate CD4+ T cell effector and regulatory functions

We built a computational model of complex mechanisms at the intersection of immunity and metabolism that regulate CD4+ T cell effector and regulatory functions by using coupled ordinary differential equations. The model provides an improved understanding of how CD4+ T cells are shaping the immune response during Clostridioides difficile infection (CDI), and how they may be targeted pharmacologically to produce a more robust regulatory (Treg) response, which is associated with improved disease outcomes during CDI and other diseases. LANCL2 activation during CDI decreased the effector response, increased regulatory response, and elicited metabolic changes that favored Treg. Interestingly, LANCL2 activation provided greater immune and metabolic modulation compared to the addition of exogenous IL-2. Additionally, we identified gluconeogenesis via PEPCK-M as potentially responsible for increased immunosuppressive behavior in Treg cells. The model can perturb immune signaling and metabolism within a CD4+ T cell and obtain clinically relevant outcomes that help identify novel drug targets for infectious, autoimmune, metabolic, and neurodegenerative diseases.

WITHDRAWN: EFFICACY, SAFETY, AND TOLERABILITY OF OMILANCOR IN A PHASE 2 RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED TRIAL OF PATIENTS WITH ULCERATIVE COLITIS

BACKGROUND

Omilancor is an oral, once-daily, gut-restricted, small molecule, first-in-class therapeutic for Crohn's disease (CD) and ulcerative colitis (UC) that targets the novel LANCL2 pathway. Through LANCL2 activation, omilancor increases the suppressive capacity of regulatory immune cells, including regulatory CD4+ T cells (Tregs), locally within the intestinal mucosa. In a Phase I study in normal healthy volunteers no changes in AEs or trends in safety laboratory trends were observed up to daily oral doses of 7500 mg/day.

METHODS

In a Phase 2, proof of concept, double blind, parallel-group study, adult patients with Mayo Clinic scores (MCS) of 4 - 10 and endoscopic subscores of 2 or more were randomly assigned to groups given omilancor 440 mg QD (n=66), omilancor 880 mg QD (n=66) or placebo (n=66) for 12 weeks. The primary endpoint was clinical remission after 12 weeks as defined by rectal bleeding (RB) equal to 0, stool frequency (SF) equal to 0 or 1 and endoscopic appearance (MES) equal to 0 or 1. A modified intent to treat (mITT) population was defined by patients with RB > 0, histological activity and elevated fecal calprotectin (FCP) at baseline. Secondary endpoints included histological remission as defined by a Geboes score < 3.1 with absence of neutrophils in the lamina propria, endoscopic remission as defined by a MES < 2, normalization of FCP and pharmacokinetics (PK) of omilancor in stool, tissue and plasma.

RESULTS

Oral omilancor was well tolerated with no trends in AE profile observed and most AEs of mild severity and no dose-limiting toxicities. In the mITT population, clinical remission was induced in 30.4% of omilancor treated patients relative to 3.7% of patients given placebo (Δ = 26.7, p = 0.01), thereby meeting the primary endpoint. Endoscopic remission was induced in 41.7% of patients treated with omilancor relative to 18.6% of patients given placebo (Δ = 23.1, p = 0.07). Histological remission was induced in 41.7% of patients treated with omilancor relative to 22.2% of patients given placebo (Δ = 19.5, p = 0.14). In patients with elevated baseline FCP, normalization occurred in 43.8% of the omilancor 880 mg group and 40.6% of the omilancor 440 mg group relative to 21.4% of the placebo group after 2 weeks (p = 0.048). PK analysis validated a gut-restricted profile with stable drug levels in stool over the 12-week treatment period and penetration into colonic biopsy tissue with limited systemic exposure. Reduction of patient reported outcomes occurred during the OLE with nearly 90% of patients reaching SF ≤ 1 and RB = 0 after 36 weeks of open-label treatment.

CONCLUSIONS

Once a day oral dosing with omilancor was well-tolerated and induced clinical remission in a Phase II mild to moderate UC population. A Phase II study in CD and a Phase III program in UC (PACIFY) were initiated in 2021 and are currently recruiting.

Exploratory studies with NX-13: oral toxicity and pharmacokinetics in rodents of an orally active, gut-restricted first-in-class therapeutic for IBD that targets NLRX1

Nucleotide-binding oligomerization domain, leucine rich repeat containing X1 (NLRX1) is an emerging therapeutic target for a spectrum of human diseases. NX-13 is a small molecule therapeutic designed to target and activate NLRX1 to induce immunometabolic changes resulting in lower inflammation and therapeutic responses in inflammatory bowel disease (IBD). This study investigates the safety of NX-13 in a seven-day, repeat-dose general toxicity study in male and female Sprague Dawley rats at oral doses of 500 and 1000 mg/kg. Weights, clinical signs, functional observational battery, clinical pathology and histopathology were used for evaluation. Daily oral dosing of NX-13 up to 1000 mg/kg did not result in any changes in weight, abnormal clinical signs or behavior. No significant differences were observed between treated and control rats in hematology or blood biochemistry. Histopathological evaluation of 12 tissues demonstrated no differences between controls and treated rats. There were no changes in weights of brain, heart, kidney, liver or spleen. Pharmacokinetic analysis of a single oral dose of NX-13 at 10 mg/kg in Sprague Dawley rats provided a maximum plasma concentration of 57 ng/mL at 0.5 h post-dose. Analysis of colon tissue after oral dosing with 1 and 10 mg/kg indicated high peak concentrations (10 and 100 µg/g, respectively) that scale in a dose-proportional manner. These experiments suggest that NX-13 is safe and well-tolerated in rats given oral doses as high as 1000 mg/kg with a favorable gastrointestinal localized pharmacokinetic profile, confirming NX-13 as a promising therapeutic for Crohn's disease and ulcerative colitis.

Nlrx1-Regulated Defense and Metabolic Responses to Aspergillus fumigatus Are Morphotype and Cell Type Specific

The Nlr family member X1 (Nlrx1) is an immuno-metabolic hub involved in mediating effective responses to virus, bacteria, fungi, cancer, and auto-immune diseases. We have previously shown that Nlrx1 is a critical regulator of immune signaling and mortality in several models of pulmonary fungal infection using the clinically relevant fungus Aspergillus fumigatus. In the absence of Nlrx1, hosts produce an enhanced Th2 response primarily by CD103+ dendritic cell populations resulting in enhanced mortality via immunopathogenesis as well as enhanced fungal burden. Here, we present our subsequent efforts showcasing loss of Nlrx1 resulting in a decreased ability of host cells to process A. fumigatus conidia in a cell-type-specific manner by BEAS-2B airway epithelial cells, alveolar macrophages, bone marrow-derived macrophages, but not bone marrow-derived neutrophils. Furthermore, loss of Nlrx1 results in a diminished ability to generate superoxide and/or generic reactive oxygen species during specific responses to fungal PAMPs, conidia, and hyphae. Analysis of glycolysis and mitochondrial function suggests that Nlrx1 is needed to appropriately shut down glycolysis in response to A. fumigatus conidia and increase glycolysis in response to hyphae in BEAS-2B cells. Blocking glycolysis and pentose phosphate pathway (PPP) via 2-DG and NADPH production through glucose-6-phosphate dehydrogenase inhibitor resulted in significantly diminished conidial processing in wild-type BEAS-2B cells to the levels of Nlrx1-deficient BEAS-2B cells. Our findings suggest a need for airway epithelial cells to generate NADPH for reactive oxygen species production in response to conidia via PPP. In context to fungal pulmonary infections, our results show that Nlrx1 plays significant roles in host defense via PPP modulation of several aspects of metabolism, particularly glycolysis, to facilitate conidia processing in addition to its critical role in regulating immune signaling.

Enemy of My Enemy: A Novel Insect-Specific Flavivirus Offers a Promising Platform for a Zika Virus Vaccine

Vaccination remains critical for viral disease outbreak prevention and control, but conventional vaccine development typically involves trade-offs between safety and immunogenicity. We used a recently discovered insect-specific flavivirus as a vector in order to develop an exceptionally safe, flavivirus vaccine candidate with single-dose efficacy. To evaluate the safety and efficacy of this platform, we created a chimeric Zika virus (ZIKV) vaccine candidate, designated Aripo/Zika virus (ARPV/ZIKV). ZIKV has caused immense economic and public health impacts throughout the Americas and remains a significant public health threat. ARPV/ZIKV vaccination showed exceptional safety due to ARPV/ZIKV’s inherent vertebrate host-restriction. ARPV/ZIKV showed no evidence of replication or translation in vitro and showed no hematological, histological or pathogenic effects in vivo. A single-dose immunization with ARPV/ZIKV induced rapid and robust neutralizing antibody and cellular responses, which offered complete protection against ZIKV-induced morbidity, mortality and in utero transmission in immune-competent and -compromised murine models. Splenocytes derived from vaccinated mice demonstrated significant CD4⁺ and CD8⁺ responses and significant cytokine production post-antigen exposure. Altogether, our results further support that chimeric insect-specific flaviviruses are a promising strategy to restrict flavivirus emergence via vaccine development.

PLXDC2 activation by PX-69 ameliorates rheumatoid arthritis through activation of novel immunometabolic mechanisms

Rheumatoid arthritis is a chronic inflammatory disorder that affects up to 1% of the population worldwide characterized by the increased presence of infiltrating immune cells, activation of inflammatory cytokine cascades, oxidative stress, abnormal proliferation of fibroblast-like synoviocytes (FLS) and neovascularization at the joint synovium. Plexin domain containing 2 (PLXDC2) is a transmembrane receptor with antioxidant, antiangiogenic and immunomodulatory properties that provide therapeutic activity in animal models of autoimmune disease, including rheumatoid arthritis. PLXDC2 activation suppresses glycolytic metabolism, while decreasing cytokine and chemokine secretion and production of superoxide species, in immune cells and FLS. In a rat model of collagen-induced arthritis, oral administration of the lead PLXDC2-binding agonist, PX-69, ameliorates disease severity, resulting in decreased clinical scores and paw size. Similarly, hind ankles presented structure preservation, reduced cartilage damage and decreased immune cell infiltration and number of blood vessels in the PX-69-treated group relative to vehicle. Immunologically, PX-69 treatment resulted in a 2-fold decrease of TNFα-producing cells while upregulating the proportion of IL-10+ myeloid cells and regulatory T cells in draining lymph nodes. In synovial tissue, pharmacological activation of PLXDC2 provided greater than 50% reduction in expression of inflammatory mediators (TNFα, IL1β, IL6, Cxcl1) and markers of synoviocyte activation (c-myc, c-fos). These results support the role of PLXDC2 signaling in controlling rheumatoid arthritis and validate PLXDC2 as a novel target for the treatment of this disabling inflammatory disorder.

BT-11 (omilancor), a first-in-class, topical therapeutic for psoriasis, ameliorates disease severity and inflammation through activation of LANCL2 pathway

BT-11 (omilancor) is a small molecule therapeutic that activates the LANCL2 pathway in immune and epithelial cells, resulting in regulatory effects at the intersection of immunity and metabolism. LANCL2 modulates the plasticity between Th17 and regulatory T cells (Tregs), favoring the stability and suppressive capacity of Tregs. Given the implication of the LANCL2 pathway in autoimmune disease and the demonstrated clinical efficacy and safety of BT-11 in a Phase 2 clinical trial of UC, we evaluated the therapeutic efficacy of BT-11 in psoriasis. In an imiquimod-induced mouse model of psoriasis, pharmacological activation of LANCL2 through topical BT-11 treatment ameliorates disease severity, resulting in over 60% reduction of PASI score. Indeed, BT-11 treatment decreased acanthosis and immune cell infiltration, with no signs of parakeratosis. The loss of LANCL2 in mice resulted in increased hyperkeratosis and parakeratosis. Local LANCL2 activation by BT-11 resulted in decreased TNF, IL17, IL6 and IL21-producing cells in the spleen. Additionally, LANCL2 activation regulated keratinocyte metabolism and function. Keratinocytes from BT-11-treated mice presented lower metabolic activation, reported as decreased ATP production, mitochondrial respiration and glucose metabolism. In translational studies with human PBMCs, BT-11 modulated the metabolic profile of CD4+ T cells at late state glycolysis, favoring oxidative pathways, and decreased expression of proinflammatory cytokines (IFNγ, TNFα), while upregulating IL-10. These results merit further exploration into the implication of LANCL2 signaling in human psoriasis and leverages the development of BT-11, as a first-in-class, topical therapeutic for psoriasis.

Variants at the MHC Region Associate With Susceptibility to Clostridioides difficile Infection: A Genome-Wide Association Study Using Comprehensive Electronic Health Records

Background

Clostridioides difficile is a major cause of healthcare-associated and community-acquired diarrhea. Host genetic susceptibility to Clostridioides difficile infection has not been studied on a large-scale.

Methods

A total of 1,160 Clostridioides difficile infection cases and 15,304 controls were identified by applying the eMERGE Clostridioides difficile infection algorithm to electronic health record data. A genome-wide association study was performed using a linear mixed model, adjusted for significant covariates in the full dataset and the antibiotic subgroup. Colocalization and MetaXcan were performed to identify potential target genes in Clostridioides difficile infection - relevant tissue types.

Results

No significant genome-wide association was found in the meta-analyses of the full Clostridioides difficile infection dataset. One genome-wide significant variant, rs114751021, was identified (OR = 2.42; 95%CI = 1.84-3.11; p=4.50 x 10^-8) at the major histocompatibility complex region associated with Clostridioides difficile infection in the antibiotic group. Colocalization and MetaXcan identified MICA, C4A/C4B, and NOTCH4 as potential target genes. Down-regulation of MICA, upregulation of C4A and NOTCH4 was associated with a higher risk for Clostridioides difficile infection.

Conclusions

Leveraging the EHR and genetic data, genome-wide association, and fine-mapping techniques, this study identified variants and genes associated with Clostridioides difficile infection, provided insights into host immune mechanisms, and described the potential for novel treatment strategies for Clostridioides difficile infection. Future replication and functional validation are needed.

NLRX1 is a key regulator of immune signaling during invasive pulmonary aspergillosis

Aspergillus fumigatus is an opportunistic fungal pathogen of immunocompromised patient populations. Mortality is thought to be context-specific and occurs via both enhanced fungal growth and immunopathogenesis. NLRX1 is a negative regulator of immune signaling and metabolic pathways implicated in host responses to microbes, cancers, and autoimmune diseases. Our study indicates loss of Nlrx1 results in enhanced fungal burden, pulmonary inflammation, immune cell recruitment, and mortality across immuno-suppressed and immuno-competent models of IPA using two clinically derived isolates (AF293, CEA10). We observed that the heightened mortality is due to enhanced recruitment of CD103+ dendritic cells (DCs) that produce elevated amounts of IL-4 resulting in a detrimental Th2-mediated immune response. Adoptive transfer of Nlrx1-/- CD103+ DCs in neutropenic NRG mice results in enhanced mortality that can be ablated using IL-4 neutralizing antibodies. In vitro analysis of CD103+ DCs indicates loss of Nlrx1 results in enhanced IL-4 production via elevated activation of the JNK/JunB pathways. Interestingly, loss of Nlrx1 also results in enhanced recruitment of monocytes and neutrophils. Chimeras of irradiated Nlrx1-/- mice reconstituted with wild type bone marrow have enhanced neutrophil recruitment and survival during models of IPA. This enhanced immune cell recruitment in the absence of Nlrx1 is mediated by excessive production of CXCL8/IL-8 family of chemokines and IL-6 via early and enhanced activation of P38 in response to A. fumigatus conidia as shown in BEAS-2B airway epithelial cells. In summary, our results point strongly towards the cell-specific and contextual function of Nlrx1 during invasive pulmonary aspergillosis and may lead to novel therapeutics to reduce Th2 responses by CD103+ DCs or heightened recruitment of neutrophils.

Fungal infections are mitigated and controlled in part by a robust immune response and generation of reactive oxygen species. In certain instances, the immune response may become harmful to the host. Nlrx1 is a known negative regulator of inflammatory aspects of the immune system in response to viruses, bacteria, and cancers. In this study we describe the novel importance of Nlrx1 in controlling and fighting fungal infections in two different host cell populations through two distinct mechanisms. Nlrx1 may function as a future target to mitigate inflammation and immunopathogenesis during fungal pulmonary infection as well as enhance beneficial neutrophil recruitment.

Abscisic acid enriched fig extract promotes insulin sensitivity by decreasing systemic inflammation and activating LANCL2 in skeletal muscle

Abscisic acid is a phytohormone found in fruits and vegetables and is endogenously produced in mammals. In humans and mice, lanthionine synthetase C-like 2 (LANCL2) has been characterized as the natural receptor for ABA. Herein, we characterize the efficacy of a fig fruit extract of ABA in promoting glycemic control. This ABA-enriched extract, at 0.125 µg ABA/kg body weight, improves glucose tolerance, insulin sensitivity and fasting blood glucose in diet-induced obesity (DIO) and db/db mouse models. In addition to decreasing systemic inflammation and providing glycemic control without increasing insulin, ABA extract modulates the metabolic activity of muscle. ABA increases expression of important glycogen synthase, glucose, fatty acid and mitochondrial metabolism genes and increases direct measures of fatty acid oxidation, glucose oxidation and metabolic flexibility in soleus muscle cells from ABA-treated mice with DIO. Glycolytic and mitochondrial ATP production were increased in ABA-treated human myotubes. Further, ABA synergized with insulin to dramatically increase the rate of glycogen synthesis. The loss of LANCL2 in skeletal muscle abrogated the effect of ABA extract in the DIO model and increased fasting blood glucose levels. This data further supports the clinical development of ABA in the treatment of pre-diabetes, type 2 diabetes and metabolic syndrome.

Malnutrition, Health and the Role of Machine Learning in Clinical Setting

Nutrition plays a vital role in health and the recovery process. Deficiencies in macronutrients and micronutrients can impact the development and progression of various disorders. However, malnutrition screening tools and their utility in the clinical setting remain largely understudied. In this study, we summarize the importance of nutritional adequacy and its association with neurological, cardiovascular, and immune-related disorders. We also examine general and specific malnutrition assessment tools utilized in healthcare settings. Since the implementation of the screening process in 2016, malnutrition data from hospitalized patients in the Geisinger Health System is presented and discussed as a case study. Clinical data from five Geisinger hospitals shows that ~10% of all admitted patients are acknowledged for having some form of nutritional deficiency, from which about 60-80% of the patients are targeted for a more comprehensive assessment. Finally, we conclude that with a reflection on how technological advances, specifically machine learning-based algorithms, can be integrated into electronic health records to provide decision support system to care providers in the identification and management of patients at higher risk of malnutrition.

The Safety, Tolerability, and Pharmacokinetics Profile of BT-11, an Oral, Gut-Restricted Lanthionine Synthetase C-Like 2 Agonist Investigational New Drug for Inflammatory Bowel Disease: A Randomized, Double-Blind, Placebo-Controlled Phase I Clinical Trial

BT-11 is a new oral, gut-restricted, first-in-class investigational drug for Crohn disease (CD) and ulcerative colitis (UC) that targets the lanthionine synthetase C-like 2 (LANCL2) pathway and immunometabolic mechanisms. Oral BT-11 was assessed for safety, tolerability, and pharmacokinetics (PK) in normal healthy volunteers (n = 70) in a randomized, double-blind, placebo-controlled trial. Subjects (n = 70) were randomly assigned to one of five single ascending dose cohorts (up to 100 mg/kg, p.o.) and three multiple ascending dose cohorts [up to 100 mg/kg daily (QD) for seven days, orally]. Safety and tolerability were assessed by adverse event (AE) reporting, vital signs, electrocardiogram, hematology, and clinical chemistry. BT-11 did not increase total or gastrointestinal AE rates, as compared with placebo, and no serious adverse events were observed. Oral BT-11 dosing does not result in any clinically significant findings by biochemistry, coagulation, electrocardiogram, hematology, or urinalysis as compared with placebo. Mean fecal concentrations of BT-11 increased linearly with increasing oral doses, with 2.39 mg/g at 7.7 mg/kg on day 7 of the multiple ascending dose (MAD). Analysis of plasma pharmacokinetics indicates that maximum systemic concentrations are approximately 1/6000th of observed concentrations in feces and the distal gastrointestinal tract. Fecal calprotectin levels were lower in BT-11 treated groups as compared to placebo. BT-11 significantly decreases interferon gamma positive (IFNγ+) and tumor necrosis factor alpha positive (TNFα+) cluster of differentiation 4 positive (CD4+) T cells and increases forkhead box P3 positive (FOXP3+) CD4+ T cells in colonic lamina propria mononuclear cells from patients with CD and patients with UC at concentrations of 0.01 µM when treated ex vivo. BT-11 treatment is well-tolerated with no dose-limiting toxicities up to daily oral doses of 100 mg/kg (16 tablets); whereas the efficacious dose is a single tablet (8 mg/kg). Phase II studies in CD and UC patients are ongoing.

High-resolution computational modeling of immune responses in the gut

Background

Helicobacter pylori causes gastric cancer in 1–2% of cases but is also beneficial for protection against allergies and gastroesophageal diseases. An estimated 85% of H. pylori–colonized individuals experience no detrimental effects. To study the mechanisms promoting host tolerance to the bacterium in the gastrointestinal mucosa and systemic regulatory effects, we investigated the dynamics of immunoregulatory mechanisms triggered by H. pylori using a high-performance computing–driven ENteric Immunity SImulator multiscale model. Immune responses were simulated by integrating an agent-based model, ordinary, and partial differential equations.

Results

The outputs were analyzed using 2 sequential stages: the first used a partial rank correlation coefficient regression–based and the second a metamodel-based global sensitivity analysis. The influential parameters screened from the first stage were selected to be varied for the second stage. The outputs from both stages were combined as a training dataset to build a spatiotemporal metamodel. The Sobol indices measured time-varying impact of input parameters during initiation, peak, and chronic phases of infection. The study identified epithelial cell proliferation and epithelial cell death as key parameters that control infection outcomes. In silico validation showed that colonization with H. pylori decreased with a decrease in epithelial cell proliferation, which was linked to regulatory macrophages and tolerogenic dendritic cells.

Conclusions

The hybrid model of H. pylori infection identified epithelial cell proliferation as a key factor for successful colonization of the gastric niche and highlighted the role of tolerogenic dendritic cells and regulatory macrophages in modulating the host responses and shaping infection outcomes.

Activation of NLRX1 by NX-13 Alleviates Inflammatory Bowel Disease through Immunometabolic Mechanisms in CD4+ T Cells

Inflammatory bowel disease (IBD) is a complex autoimmune disease with dysfunction in pattern-recognition responses, including within the NLR family. Nucleotide-binding oligomerization domain, leucine rich repeat containing X1 (NLRX1) is a unique NLR with regulatory and anti-inflammatory functions resulting in protection from IBD in mouse models. NX-13 is an orally active, gut-restricted novel drug candidate that selectively targets and activates the NLRX1 pathway locally in the gut. In vitro and in vivo efficacy of NLRX1 activation by NX-13 was examined. Oral treatment with NX-13 alleviates disease severity, colonic leukocytic infiltration, and cytokine markers of inflammation in three mouse models of IBD (dextran sulfate sodium, Mdr1a^-/-, and CD45RB^hi adoptive transfer). Treatment of naive CD4⁺ T cells with NX-13 in vitro decreases differentiation into Th1 and Th17 subsets with increased oxidative phosphorylation and decreased NF-κB activation and reactive oxygen species. With stimulation by PMA/ionomycin, TNF-α, or H₂O₂, PBMCs from ulcerative colitis patients treated with NX-13 had decreased NF-κB activity, TNF-α⁺ and IFN-γ⁺ CD4⁺ T cells and overall production of IL-6, MCP1, and IL-8. NX-13 activates NLRX1 to mediate a resistance to both inflammatory signaling and oxidative stress in mouse models and human primary cells from ulcerative colitis patients with effects on NF-κB activity and oxidative phosphorylation. NX-13 is a promising oral, gut-restricted NLRX1 agonist for treating IBD.

Abscisic Acid Standardized Fig (Ficus carica) Extracts Ameliorate Postprandial Glycemic and Insulinemic Responses in Healthy Adults

Abscisic acid (ABA) can improve glucose homeostasis and reduce inflammation in mammals by activating lanthionine synthetase C-like 2 (LANCL2). This study examined the effects of two fig fruit extracts (FFEs), each administered at two different ABA doses, on glycemic index (GI) and insulinemic index (II) to a standard glucose drink. In a randomized, double-blind crossover study, 10 healthy adults consumed 4 test beverages containing FFE with postprandial glucose and insulin assessed at regular intervals over 2 h to determine GI and II responses. Test beverages containing 200 mg FFE-50× and 1200 mg FFE-10× significantly reduced GI values by -25% (P = 0.001) and -24% (P = 0.002), respectively. Two lower doses of FFE also reduced GI values compared with the reference drink (by approximately -14%), but the differences did not reach statistical significance. Addition of FFE to the glucose solution significantly reduced II values at all dosages and displayed a clear dose-response reduction: FFE-50× at 100 mg and 200 mg (-14% (P < 0.05) and -24% (P = 0.01), respectively) and FFE-10× at 600 mg and 1200 mg (-16% (P < 0.05) and -24% (P = 0.01), respectively). FFE supplementation is a promising nutritional intervention for the management of acute postprandial glucose and insulin homeostasis, and it is a possible adjunctive treatment for glycemic management of chronic metabolic disorders such as prediabetes and type 2 diabetes mellitus.

Validation of lanthionine synthetase C-like 2 (LANCL2) as a therapeutic target for systemic lupus erythematosus

Lanthionine synthetase C-like 2 (LANCL2) is a membrane receptor with downstream effects on immunity and metabolism including the differentiation of regulatory CD4+ T cells. Its natural ligand, abscisic acid (ABA), has been shown to be decreased in autoimmune and inflammatory disease. Given the implication of the LANCL2 pathway in autoimmune disease and the progression of LANCL2-specific ligands, such as BT-11, into clinical stage development, we assessed the role of LANCL2 in systemic lupus erythematosus (SLE). In a TLR7/8 resiquimod-induced model of SLE, the loss of LANCL2 significantly decreases survival (P = 0.0008) relative to wild-type, resulting in less than 10% survival and a greater than 60% reduction relative to wild-type. Similarly, LANCL2−/− displayed greater serum anti-dsDNA antibodies and higher proteinuria. Within spleens, the loss of LANCL2 resulted in greater IL-6 and TNF, higher proportions of T follicular helper cells and lower ratios of regulatory CD4+ T cells relative to IFNγ producing cells. The greater inflammation was also mirrored in transcriptional changes at the splenic level indicating a greater susceptibility to severe disease. These results merit further exploration into the implication of LANCL2 signaling in human SLE and characterization of the therapeutic efficacy of LANCL2-specific agonists for future SLE development. Thus, LANCL2 is a novel promising therapeutic target for SLE.

Nonclinical Toxicology and Toxicokinetic Profile of an Oral Lanthionine Synthetase C-Like 2 (LANCL2) Agonist, BT-11

BT-11 is an orally active, gut-restricted investigational therapeutic targeting the lanthionine synthetase C-like 2 pathway with lead indications in ulcerative colitis (UC) and Crohn disease (CD), 2 manifestations of inflammatory bowel disease (IBD). In 5 mouse models of IBD, BT-11 is effective at oral doses of 8 mg/kg. BT-11 was also efficacious at nanomolar concentrations in primary human samples from patients with UC and CD. BT-11 was tested under Good Laboratory Practice conditions in 90-day repeat-dose general toxicity studies in rats and dogs, toxicokinetics, respiratory, cardiovascular and central nervous system safety pharmacology, and genotoxicity studies. Oral BT-11 did not cause any clinical signs of toxicity, biochemical or hematological changes, or macroscopic or microscopic changes to organs in 90-day repeat-dose toxicity studies in rats and dogs at doses up to 1,000 mg/kg/d. Oral BT-11 resulted in low systemic exposure in both rats (area under the curve exposure from t = 0 to t = 8 hours [AUC_0-8] of 216 h × ng/mL) and dogs (650 h × ng/mL) and rapid clearance with an average half-life of 3 hours. BT-11 did not induce changes in respiratory function, electrocardiogram parameters, or behavior with single oral doses of 1,000 mg/kg/d. There was no evidence of mutagenic or genotoxic potential for BT-11 up to tested limit doses using an Ames test, chromosomal aberration assay in human peripheral blood lymphocytes, or micronucleus assay in rats. Therefore, nonclinical studies show BT-11 to be a safe and well-tolerated oral therapeutic with potential as a potent immunometabolic therapy for UC and CD with no-observed adverse effect level >1,000 mg/kg in in vivo studies.

Oral Treatment with BT-11 Ameliorates Inflammatory Bowel Disease by Enhancing Regulatory T Cell Responses in the Gut

Inflammatory bowel disease (IBD) is an expanding autoimmune disease afflicting millions that remains difficult to treat due to the accumulation of multiple immunological changes. BT-11 is an investigational new drug for IBD that is orally active, gut restricted, and targets the lanthionine synthetase C-like 2 immunometabolic pathway. CD25⁺ FOXP3⁺ CD4⁺ T cells are increased locally within the colon of BT-11-treated mice in Citrobacter rodentium and IL-10^-/- mouse models of colitis. The maintained efficacy of BT-11 in the absence of IL-10 combined with the loss of efficacy when direct cell-cell interactions are prevented suggest that the regulatory T cell (Treg)-related elements of suppression are cell contact-mediated. When PD-1 is inhibited, both in vitro and in vivo, the efficacy of BT-11 is reduced, validating this assertion. The depletion of CD25⁺ cells in vivo abrogated the retention of therapeutic efficacy postdiscontinuation of treatment, indicating that Tregs are implicated in the maintenance of tolerance mediated by BT-11. Furthermore, the involvement of CD25 suggested a role of BT-11 in IL-2 signaling. Cotreatment with BT-11 and IL-2 greatly enhances the differentiation of CD25⁺ FOXP3⁺ cells from naive CD4⁺ T cells relative to either alone. BT-11 enhances phosphorylation of STAT5, providing a direct linkage to the regulation of FOXP3 transcription. Notably, when STAT5 is inhibited, the effects of BT-11 on the differentiation of Tregs are blocked. BT-11 effectively enhances the IL-2/STAT5 signaling axis to induce the differentiation and stability of CD25⁺ FOXP3⁺ cells in the gastrointestinal mucosa to support immunoregulation and immunological tolerance in IBD.

Activation of LANCL2 by BT-11 Ameliorates IBD by Supporting Regulatory T Cell Stability Through Immunometabolic Mechanisms

BACKGROUND

Inflammatory bowel disease (IBD) afflicts 5 million people and is increasing in prevalence. There is an unmet clinical need for safer and effective treatments for IBD. The BT-11 is a small molecule oral therapeutic that ameliorates IBD by targeting lanthionine synthetase C-like 2 (LANCL2) and has a benign safety profile in rats.

METHODS

Mdr1a-/-, dextran sodium sulphate , and adoptive transfer mouse models of colitis were employed to validate therapeutic efficacy and characterize the mechanisms of therapeutic efficacy of BT-11. In vitro cultures of CD4+ T cell differentiation and human peripheral blood mononuclear cells from Crohn's disease patients were used to determine its potential for human translation.

RESULTS

BT-11 reduces inflammation in multiple mouse models of IBD. Oral treatment with BT-11 increases the numbers of lamina propria regulatory T cells (Tregs) in a LANCL2-dependent manner. In vitro, BT-11 increases the differentiation in Treg phenotypes, the upregulation of genes implicated in Treg cell stability, and conditions Treg cells to elicit greater suppressive actions. These immunoregulatory effects are intertwined with the ability of BT-11 to regulate late stage glycolysis and tricarboxylic acid cycle. Immunometabolic mechanistic findings translate into human peripheral blood mononuclear cells from healthy individuals and Crohn's disease patients.

CONCLUSIONS

BT-11 is a safe, efficacious oral therapeutic for IBD with a human translatable mechanism of action that involves activation of LANCL2, immunometabolic modulation of CD4+ T cell subsets leading to stable regulatory phenotypes in the colonic LP.

NLRX1 Modulates Immunometabolic Mechanisms Controlling the Host-Gut Microbiota Interactions during Inflammatory Bowel Disease

Interactions among the gut microbiome, dysregulated immune responses, and genetic factors contribute to the pathogenesis of inflammatory bowel disease (IBD). Nlrx1^−/− mice have exacerbated disease severity, colonic lesions, and increased inflammatory markers. Global transcriptomic analyses demonstrate enhanced mucosal antimicrobial defense response, chemokine and cytokine expression, and epithelial cell metabolism in colitic Nlrx1^−/− mice compared to wild-type (WT) mice. Cell-specificity studies using cre-lox mice demonstrate that the loss of NLRX1 in intestinal epithelial cells (IEC) recapitulate the increased sensitivity to DSS colitis observed in whole body Nlrx1^−/− mice. Further, organoid cultures of Nlrx1^−/− and WT epithelial cells confirm the altered patterns of proliferation, amino acid metabolism, and tight junction expression. These differences in IEC behavior can impact the composition of the microbiome. Microbiome analyses demonstrate that colitogenic bacterial taxa such as Veillonella and Clostridiales are increased in abundance in Nlrx1^−/− mice and in WT mice co-housed with Nlrx1^−/− mice. The transfer of an Nlrx1^−/−-associated gut microbiome through co-housing worsens disease in WT mice confirming the contributions of the microbiome to the Nlrx1^−/− phenotype. To validate NLRX1 effects on IEC metabolism mediate gut–microbiome interactions, restoration of WT glutamine metabolic profiles through either exogenous glutamine supplementation or administration of 6-diazo-5-oxo-l-norleucine abrogates differences in inflammation, microbiome, and overall disease severity in Nlrx1^−/− mice. The influence NLRX1 deficiency on SIRT1-mediated effects is identified to be an upstream controller of the Nlrx1^−/− phenotype in intestinal epithelial cell function and metabolism. The altered IEC function and metabolisms leads to changes in barrier permeability and microbiome interactions, in turn, promoting greater translocation and inflammation and resulting in an increased disease severity. In conclusion, NLRX1 is an immunoregulatory molecule and a candidate modulator of the interplay between mucosal inflammation, metabolism, and the gut microbiome during IBD.

Modulation of Immune Signaling and Metabolism Highlights Host and Fungal Transcriptional Responses in Mouse Models of Invasive Pulmonary Aspergillosis

Incidences of invasive pulmonary aspergillosis, an infection caused predominantly by Aspergillus fumigatus, have increased due to the growing number of immunocompromised individuals. While A. fumigatus is reliant upon deficiencies in the host to facilitate invasive disease, the distinct mechanisms that govern the host-pathogen interaction remain enigmatic, particularly in the context of distinct immune modulating therapies. To gain insights into these mechanisms, RNA-Seq technology was utilized to sequence RNA derived from lungs of 2 clinically relevant, but immunologically distinct murine models of IPA on days 2 and 3 post inoculation when infection is established and active disease present. Our findings identify notable differences in host gene expression between the chemotherapeutic and steroid models at the interface of immunity and metabolism. RT-qPCR verified model specific and nonspecific expression of 23 immune-associated genes. Deep sequencing facilitated identification of highly expressed fungal genes. We utilized sequence similarity and gene expression to categorize the A. fumigatus putative in vivo secretome. RT-qPCR suggests model specific gene expression for nine putative fungal secreted proteins. Our analysis identifies contrasting responses by the host and fungus from day 2 to 3 between the two models. These differences may help tailor the identification, development, and deployment of host- and/or fungal-targeted therapeutics.

Agents and networks to model the dynamic interactions of intracellular transport

Cell biology is increasingly evolving to become a more formal and quantitative science. The field of intracellular transport is no exception. However, it is extremely challenging to formulate mathematical and computational models for processes that involve dynamic structures that continuously change their shape, position and composition, leading to information transfer and functional outcomes. The two major strategies employed to represent intracellular trafficking are based on "ordinary differential equations" and "agent-" based modeling. Both approaches have advantages and drawbacks. Combinations of both modeling strategies have promising characteristics to generate meaningful simulations for intracellular transport and allow the formulation of new hypotheses and provide new insights. In the near future, cell biologists will encounter and hopefully overcome the challenge of translating descriptive cartoon representations of biological systems into mathematical network models.

Abscisic Acid: A Novel Nutraceutical for Glycemic Control

Abscisic acid is naturally present in fruits and vegetables, and it plays an important role in managing glucose homeostasis in humans. According to the latest U.S. dietary survey, about 92% of the population might have a deficient intake of ABA due to their deficient intake of fruits and vegetables. This review summarizes the in vitro, preclinical, mechanistic, and human translational findings obtained over the past 15 years in the study of the role of ABA in glycemic control. In 2007, dietary ABA was first reported to ameliorate glucose tolerance and obesity-related inflammation in mice. The most recent findings regarding the topic of ABA and its proposed receptor lanthionine synthetase C-like 2 in glycemic control and their interplay with insulin and glucagon-like peptide-1 suggest a major role for ABA in the physiological response to a glucose load in humans. Moreover, emerging evidence suggests that the ABA response might be dysfunctional in diabetic subjects. Follow on intervention studies in healthy individuals show that low-dose dietary ABA administration exerts a beneficial effect on the glycemia and insulinemia profiles after oral glucose load. These recent findings showing benefits in humans, together with extensive efficacy data in mouse models of diabetes and inflammatory disease, suggest the need for reference ABA values and its possible exploitation of the glycemia-lowering effects of ABA for preventative purposes. Larger clinical studies on healthy, prediabetic, and diabetic subjects are needed to determine whether addressing the widespread dietary ABA deficiency improves glucose control in humans.

Novel Screening Tool for Stroke Using Artificial Neural Network

Background and Purpose—

The timely diagnosis of stroke at the initial examination is extremely important given the disease morbidity and narrow time window for intervention. The goal of this study was to develop a supervised learning method to recognize acute cerebral ischemia (ACI) and differentiate that from stroke mimics in an emergency setting.

Methods—

Consecutive patients presenting to the emergency department with stroke-like symptoms, within 4.5 hours of symptoms onset, in 2 tertiary care stroke centers were randomized for inclusion in the model. We developed an artificial neural network (ANN) model. The learning algorithm was based on backpropagation. To validate the model, we used a 10-fold cross-validation method.

Results—

A total of 260 patients (equal number of stroke mimics and ACIs) were enrolled for the development and validation of our ANN model. Our analysis indicated that the average sensitivity and specificity of ANN for the diagnosis of ACI based on the 10-fold cross-validation analysis was 80.0% (95% confidence interval, 71.8–86.3) and 86.2% (95% confidence interval, 78.7–91.4), respectively. The median precision of ANN for the diagnosis of ACI was 92% (95% confidence interval, 88.7–95.3).

Conclusions—

Our results show that ANN can be an effective tool for the recognition of ACI and differentiation of ACI from stroke mimics at the initial examination.

Cooperation of Gastric Mononuclear Phagocytes with Helicobacter pylori during Colonization

Helicobacter pylori, the dominant member of the human gastric microbiota, elicits immunoregulatory responses implicated in protective versus pathological outcomes. To evaluate the role of macrophages during infection, we employed a system with a shifted proinflammatory macrophage phenotype by deleting PPARγ in myeloid cells and found a 5- to 10-fold decrease in gastric bacterial loads. Higher levels of colonization in wild-type mice were associated with increased presence of mononuclear phagocytes and in particular with the accumulation of CD11b+F4/80hiCD64+CX3CR1+ macrophages in the gastric lamina propria. Depletion of phagocytic cells by clodronate liposomes in wild-type mice resulted in a reduction of gastric H. pylori colonization compared with nontreated mice. PPARγ-deficient and macrophage-depleted mice presented decreased IL-10-mediated myeloid and T cell regulatory responses soon after infection. IL-10 neutralization during H. pylori infection led to increased IL-17-mediated responses and increased neutrophil accumulation at the gastric mucosa. In conclusion, we report the induction of IL-10-driven regulatory responses mediated by CD11b+F4/80hiCD64+CX3CR1+ mononuclear phagocytes that contribute to maintaining high levels of H. pylori loads in the stomach by modulating effector T cell responses at the gastric mucosa.

Lanthionine Synthetase C-Like 2 Modulates Immune Responses to Influenza Virus Infection

Broad-based, host-targeted therapeutics have the potential to ameliorate viral infections without inducing antiviral resistance. We identified lanthionine synthetase C-like 2 (LANCL2) as a new therapeutic target for immunoinflammatory diseases. To examine the therapeutic efficacy of oral NSC61610 administration on influenza, we infected C57BL/6 mice with influenza A H1N1pdm virus and evaluated influenza-related mortality, lung inflammatory profiles, and pulmonary histopathology. Oral treatment with NSC61610 ameliorates influenza virus infection by down-modulating pulmonary inflammation through the downregulation of TNF-α and MCP-1 and reduction in the infiltration of neutrophils. NSC61610 treatment increases IL10-producing CD8+ T cells and macrophages in the lungs during the resolution phase of disease. The loss of LANCL2 or neutralization of IL-10 in mice infected with influenza virus abrogates the ability of NSC61610 to accelerate recovery and induce IL-10-mediated regulatory responses. These studies validate that oral treatment with NSC61610 ameliorates morbidity and mortality and accelerates recovery during influenza virus infection through a mechanism mediated by activation of LANCL2 and subsequent induction of IL-10 responses by CD8+ T cells and macrophages in the lungs.

NLRX1 Regulates Effector and Metabolic Functions of CD4+ T Cells

Nucleotide oligomerization domain-like receptor X1 (NLRX1) has been implicated in viral response, cancer progression, and inflammatory disorders; however, its role as a dual modulator of CD4⁺ T cell function and metabolism has not been defined. The loss of NLRX1 results in increased disease severity, populations of Th1 and Th17 cells, and inflammatory markers (IFN-γ, TNF-α, and IL-17) in mice with dextran sodium sulfate-induced colitis. To further characterize this phenotype, we used in vitro CD4⁺ T cell-differentiation assays and show that NLRX1-deficient T cells have a greater ability to differentiate into an inflammatory phenotype and possess greater proliferation rates. Further, NLRX1^-/- cells have a decreased responsiveness to immune checkpoint pathways and greater rates of lactate dehydrogenase activity. When metabolic effects of the knockout are impaired, NLRX1-deficient cells do not display significant differences in differentiation or proliferation. To confirm the role of NLRX1 specifically in T cells, we used an adoptive-transfer model of colitis. Rag2^-/- mice receiving NLRX1^-/- naive or effector T cells experienced increased disease activity and effector T cell populations, whereas no differences were observed between groups receiving wild-type or NLRX1^-/- regulatory T cells. Metabolic effects of NLRX1 deficiency are observed in a CD4-specific knockout of NLRX1 within a Citrobacter rodentium model of colitis. The aerobic glycolytic preference in NLRX1^-/- effector T cells is combined with a decreased sensitivity to immunosuppressive checkpoint pathways to provide greater proliferative capabilities and an inflammatory phenotype bias leading to increased disease severity.

Modeling the Mechanisms by Which HIV-Associated Immunosuppression Influences HPV Persistence at the Oral Mucosa

Human immunodeficiency virus (HIV)-infected patients are at an increased risk of co-infection with human papilloma virus (HPV), and subsequent malignancies such as oral cancer. To determine the role of HIV-associated immune suppression on HPV persistence and pathogenesis, and to investigate the mechanisms underlying the modulation of HPV infection and oral cancer by HIV, we developed a mathematical model of HIV/HPV co-infection. Our model captures known immunological and molecular features such as impaired HPV-specific effector T helper 1 (Th1) cell responses, and enhanced HPV infection due to HIV. We used the model to determine HPV prognosis in the presence of HIV infection, and identified conditions under which HIV infection alters HPV persistence in the oral mucosa system. The model predicts that conditions leading to HPV persistence during HIV/HPV co-infection are the permissive immune environment created by HIV and molecular interactions between the two viruses. The model also determines when HPV infection continues to persist in the short run in a co-infected patient undergoing antiretroviral therapy. Lastly, the model predicts that, under efficacious antiretroviral treatment, HPV infections will decrease in the long run due to the restoration of CD4+ T cell numbers and protective immune responses.

Exploratory Studies With BT-11: A Proposed Orally Active Therapeutic for Crohn's Disease

Lanthionine synthetase cyclase-like receptor 2 (LANCL2) is a novel therapeutic target for Crohn's disease (CD). BT-11 is a small molecule that binds LANCL2, is orally active, and has demonstrated therapeutic efficacy in 3 validated mouse models of colitis at doses as low as 8 mg/kg/d. Exploratory experiments evaluated BT-11 in male Harlan Sprague Dawley rats with a single oral dose of 500 mg/kg and 80 mg/kg/d for 14 days (n = 10 rats dosed/group). Treated and control rats were observed for behavioral detriments, and blood and tissues were collected for clinical pathology and histopathological examination. A functional observational battery demonstrated no differences between treated and control groups over multiple times of observation for quantal, categorical, and continuous end points, including posture, in cage activity, approach, response to touch, weight, grip strength, body temperature, and time on a rotarod. Histopathological examination of the brain, kidney, liver, adrenal gland, testes, stomach, small and large intestines, duodenum, pancreas, heart, lungs, spleen, thymus, and rib found no significant differences between the groups. Plasma enzymes associated with liver function were transiently elevated 2 to 4 days after the 500 mg/kg single dose but returned to normal values by 8 days and were not observed at any time in rats given 80 mg/kg/d for 14 days. One hour after oral administration of a single dose of 80 mg/kg, BT-11 had a maximal concentration of 21 ng/mL; the half-life was 3 hours. These experimental results demonstrated that BT-11 is well tolerated in rats, and, with further testing, may hold promise as an orally active therapeutic for CD.

Bistability analyses of CD4+ T follicular helper and regulatory cells during Helicobacter pylori infection

T follicular helper (Tfh) cells are a highly plastic subset of CD4+ T cells specialized in providing B cell help and promoting inflammatory and effector responses during infectious and immune-mediate diseases. Helicobacter pylori is the dominant member of the gastric microbiota and exerts both beneficial and harmful effects on the host. Chronic inflammation in the context of H. pylori has been linked to an upregulation in T helper (Th)1 and Th17 CD4+ T cell phenotypes, controlled in part by the cytokine, interleukin-21. This study investigates the differentiation and regulation of Tfh cells, major producers of IL-21, in the immune response to H. pylori challenge. To better understand the conditions influencing the promotion and inhibition of a chronically elevated Tfh population, we used top-down and bottom-up approaches to develop computational models of Tfh and T follicular regulatory (Tfr) cell differentiation. Stability analysis was used to characterize the presence of two bi-stable steady states in the calibrated Tfh/Tfr models. Stochastic simulation was used to illustrate the ability of the parameter set to dictate two distinct behavioral patterns. Furthermore, sensitivity analysis helped identify the importance of various parameters on the establishment of Tfh and Tfr cell populations. The core network model was expanded into a more comprehensive and predictive model by including cytokine production and signaling pathways. From the expanded network, the interaction between TGFB-Induced Factor Homeobox 1 (Tgif1) and the retinoid X receptor (RXR) was displayed to exert control over the determination of the Tfh response. Model simulations predict that Tgif1 and RXR respectively induce and curtail Tfh responses. This computational hypothesis was validated experimentally by assaying Tgif1, RXR and Tfh in stomachs of mice infected with H. pylori.

Modeling-Enabled Systems Nutritional Immunology

This review highlights the fundamental role of nutrition in the maintenance of health, the immune response, and disease prevention. Emerging global mechanistic insights in the field of nutritional immunology cannot be gained through reductionist methods alone or by analyzing a single nutrient at a time. We propose to investigate nutritional immunology as a massively interacting system of interconnected multistage and multiscale networks that encompass hidden mechanisms by which nutrition, microbiome, metabolism, genetic predisposition, and the immune system interact to delineate health and disease. The review sets an unconventional path to apply complex science methodologies to nutritional immunology research, discovery, and development through “use cases” centered around the impact of nutrition on the gut microbiome and immune responses. Our systems nutritional immunology analyses, which include modeling and informatics methodologies in combination with pre-clinical and clinical studies, have the potential to discover emerging systems-wide properties at the interface of the immune system, nutrition, microbiome, and metabolism.

Abstract 166: Supervised Learning Based Detection of Stroke and Stroke Mimic

Background & Purpose: Up to 30% of treated patients for suspected acute ischemic stroke (AIS) could be stroke mimic (SM). Using a balanced clinical dataset, we have developed a supervised learning method from artificial intelligence to classify AIS/transient ischemic attack (TIA) and SM in an emergency room (ER) setting.

Methods: We labeled and randomly partitioned consecutive patients who received intravenous thrombolysis for suspected AIS in three tertiary centers during a three year period. The clinical data includes patients’ demographic information, past medical history, blood pressure and glucose level at presentation, NIH Stroke Scale, and presence of facial weakness. The clinical data were used to create a balanced training and testing set. We developed an Artificial Neural Network (ANN) model on patients’ clinical data, using the training set ( Figure 1). The model was used to classify the diagnosis of AIS/TIA versus SM. The ANN model was subsequently assessed using the testing set. In addition, we compared the ANN model with three regression models (ordinary least squares, logistic, and reduced logistic model).

Results: In total 803 patients (mean age 62±15 years, 52% men, median admission NIHSS-score: 6 points, IQR 3-11) were analyzed. Data from 56 random patients, not included in the training set, were used to test the model. Of 56 predictions, 49 were correct (19 out of 20 correct prediction for SM, and 30 out of 36 correct prediction for AIS/TIA). Additional analysis indicated that the model detects SM with 95% sensitivity (95%, CI: 73-99%) and 83% specificity (95%, CI: 66-93%). We further performed a 10-fold cross validation to better estimate the performance of the model. In addition, the three regression models were comparable to the ANN model at a specific adjusted threshold.

Conclusions: This study highlights a potential for ANN to discriminate AIS/TIA and SM. This model can be further optimized and integrated in patient management software in an ER setting.

Systems-wide analyses of mucosal immune responses to Helicobacter pylori at the interface between pathogenicity and symbiosis

Helicobacter pylori is the dominant member of the gastric microbiota in over half of the human population of which 5-15% develop gastritis or gastric malignancies. Immune responses to H. pylori are characterized by mixed T helper cell, cytotoxic T cell and NK cell responses. The presence of Tregs is essential for the control of gastritis and together with regulatory CX3CR1+ mononuclear phagocytes and immune-evasion strategies they enable life-long persistence of H. pylori. This H. pylori-induced regulatory environment might contribute to its cross-protective effect in inflammatory bowel disease and obesity. Here we review host-microbe interactions, the development of pro- and anti-inflammatory immune responses and how the latter contribute to H. pylori's role as beneficial member of the gut microbiota. Furthermore, we present the integration of existing and new data into a computational/mathematical model and its use for the investigation of immunological mechanisms underlying initiation, progression and outcomes of H. pylori infection.

Modeling-Enabled Characterization of Novel NLRX1 Ligands

Nucleotide-binding domain and leucine-rich repeat containing (NLR) family are intracellular sentinels of cytosolic homeostasis that orchestrate immune and inflammatory responses in infectious and immune-mediated diseases. NLRX1 is a mitochondrial-associated NOD-like receptor involved in the modulation of immune and metabolic responses. This study utilizes molecular docking approaches to investigate the structure of NLRX1 and experimentally assesses binding to naturally occurring compounds from several natural product and lipid databases. Screening of compound libraries predicts targeting of NLRX1 by conjugated trienes, polyketides, prenol lipids, sterol lipids, and coenzyme A-containing fatty acids for activating the NLRX1 pathway. The ligands of NLRX1 were identified by docking punicic acid (PUA), eleostearic acid (ESA), and docosahexaenoic acid (DHA) to the C-terminal fragment of the human NLRX1 (cNLRX1). Their binding and that of positive control RNA to cNLRX1 were experimentally determined by surface plasmon resonance (SPR) spectroscopy. In addition, the ligand binding sites of cNLRX1 were predicted in silico and validated experimentally. Target mutagenesis studies demonstrate that mutation of 4 critical residues ASP677, PHE680, PHE681, and GLU684 to alanine resulted in diminished affinity of PUA, ESA, and DHA to NLRX1. Consistent with the regulatory actions of NLRX1 on the NF-κB pathway, treatment of bone marrow derived macrophages (BMDM)s with PUA and DHA suppressed NF-κB activity in a NLRX1 dependent mechanism. In addition, a series of pre-clinical efficacy studies were performed using a mouse model of dextran sodium sulfate (DSS)-induced colitis. Our findings showed that the regulatory function of PUA on colitis is NLRX1 dependent. Thus, we identified novel small molecules that bind to NLRX1 and exert anti-inflammatory actions.

Modeling the Regulatory Mechanisms by Which NLRX1 Modulates Innate Immune Responses to Helicobacter pylori Infection

Helicobacter pylori colonizes half of the world’s population as the dominant member of the gastric microbiota resulting in a lifelong chronic infection. Host responses toward the bacterium can result in asymptomatic, pathogenic or even favorable health outcomes; however, mechanisms underlying the dual role of H. pylori as a commensal versus pathogenic organism are not well characterized. Recent evidence suggests mononuclear phagocytes are largely involved in shaping dominant immunity during infection mediating the balance between host tolerance and succumbing to overt disease. We combined computational modeling, bioinformatics and experimental validation in order to investigate interactions between macrophages and intracellular H. pylori. Global transcriptomic analysis on bone marrow-derived macrophages (BMDM) in a gentamycin protection assay at six time points unveiled the presence of three sequential host response waves: an early transient regulatory gene module followed by sustained and late effector responses. Kinetic behaviors of pattern recognition receptors (PRRs) are linked to differential expression of spatiotemporal response waves and function to induce effector immunity through extracellular and intracellular detection of H. pylori. We report that bacterial interaction with the host intracellular environment caused significant suppression of regulatory NLRC3 and NLRX1 in a pattern inverse to early regulatory responses. To further delineate complex immune responses and pathway crosstalk between effector and regulatory PRRs, we built a computational model calibrated using time-series RNAseq data. Our validated computational hypotheses are that: 1) NLRX1 expression regulates bacterial burden in macrophages; and 2) early host response cytokines down-regulate NLRX1 expression through a negative feedback circuit. This paper applies modeling approaches to characterize the regulatory role of NLRX1 in mechanisms of host tolerance employed by macrophages to respond to and/or to co-exist with intracellular H. pylori.

Supervised learning methods in modeling of CD4+ T cell heterogeneity

Background

Modeling of the immune system – a highly non-linear and complex system – requires practical and efficient data analytic approaches. The immune system is composed of heterogeneous cell populations and hundreds of cell types, such as neutrophils, eosinophils, macrophages, dendritic cells, T cells, and B cells. Each cell type is highly diverse and can be further differentiated into subsets with unique and overlapping functions. For example, CD4+ T cells can be differentiated into Th1, Th2, Th17, Th9, Th22, Treg, Tfh, as well as Tr1. Each subset plays different roles in the immune system. To study molecular mechanisms of cell differentiation, computational systems biology approaches can be used to represent these processes; however, the latter often requires building complex intracellular signaling models with a large number of equations to accurately represent intracellular pathways and biochemical reactions. Furthermore, studying the immune system entails integration of complex processes which occur at different time and space scales.

Methods

This study presents and compares four supervised learning methods for modeling CD4+ T cell differentiation: Artificial Neural Networks (ANN), Random Forest (RF), Support Vector Machines (SVM), and Linear Regression (LR). Application of supervised learning methods could reduce the complexity of Ordinary Differential Equations (ODEs)-based intracellular models by only focusing on the input and output cytokine concentrations. In addition, this modeling framework can be efficiently integrated into multiscale models.

Results

Our results demonstrate that ANN and RF outperform the other two methods. Furthermore, ANN and RF have comparable performance when applied to in silico data with and without added noise. The trained models were also able to reproduce dynamic behavior when applied to experimental data; in four out of five cases, model predictions based on ANN and RF correctly predicted the outcome of the system. Finally, the running time of different methods was compared, which confirms that ANN is considerably faster than RF.

Conclusions

Using machine learning as opposed to ODE-based method reduces the computational complexity of the system and allows one to gain a deeper understanding of the complex interplay between the different related entities.

Multiscale modeling of mucosal immune responses

Computational modeling techniques are playing increasingly important roles in advancing a systems-level mechanistic understanding of biological processes. Computer simulations guide and underpin experimental and clinical efforts. This study presents ENteric Immune Simulator (ENISI), a multiscale modeling tool for modeling the mucosal immune responses. ENISI's modeling environment can simulate in silico experiments from molecular signaling pathways to tissue level events such as tissue lesion formation. ENISI's architecture integrates multiple modeling technologies including ABM (agent-based modeling), ODE (ordinary differential equations), SDE (stochastic modeling equations), and PDE (partial differential equations). This paper focuses on the implementation and developmental challenges of ENISI. A multiscale model of mucosal immune responses during colonic inflammation, including CD4+ T cell differentiation and tissue level cell-cell interactions was developed to illustrate the capabilities, power and scope of ENISI MSM.

Systems Modeling of Interactions between Mucosal Immunity and the Gut Microbiome during Clostridium difficile Infection

Clostridium difficile infections are associated with the use of broad-spectrum antibiotics and result in an exuberant inflammatory response, leading to nosocomial diarrhea, colitis and even death. To better understand the dynamics of mucosal immunity during C. difficile infection from initiation through expansion to resolution, we built a computational model of the mucosal immune response to the bacterium. The model was calibrated using data from a mouse model of C. difficile infection. The model demonstrates a crucial role of T helper 17 (Th17) effector responses in the colonic lamina propria and luminal commensal bacteria populations in the clearance of C. difficile and colonic pathology, whereas regulatory T (Treg) cells responses are associated with the recovery phase. In addition, the production of anti-microbial peptides by inflamed epithelial cells and activated neutrophils in response to C. difficile infection inhibit the re-growth of beneficial commensal bacterial species. Computational simulations suggest that the removal of neutrophil and epithelial cell derived anti-microbial inhibitions, separately and together, on commensal bacterial regrowth promote recovery and minimize colonic inflammatory pathology. Simulation results predict a decrease in colonic inflammatory markers, such as neutrophilic influx and Th17 cells in the colonic lamina propria, and length of infection with accelerated commensal bacteria re-growth through altered anti-microbial inhibition. Computational modeling provides novel insights on the therapeutic value of repopulating the colonic microbiome and inducing regulatory mucosal immune responses during C. difficile infection. Thus, modeling mucosal immunity-gut microbiota interactions has the potential to guide the development of targeted fecal transplantation therapies in the context of precision medicine interventions.

Modulation of inflammation and immunity by dietary conjugated linoleic acid

Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of linoleic acid. This family of polyunsaturated fatty acids has drawn significant attention in the last three decades for its variety of biologically beneficial properties and health effects. CLA has been shown to exert various potent protective functions such as anti-inflammatory, anticarcinogenic, antiadipogenic, antidiabetic and antihypertensive properties in animal models of disease. Therefore, CLA represents a nutritional avenue to prevent lifestyle diseases or metabolic syndrome. Initially, the overall effects of CLA were thought to be the result of interactions between its two major isomers: cis-9, trans-11 and trans-10, cis-12. However, later evidence suggests that such physiological effects of CLA might be different between the isomers: t-10, c-12-CLA is thought to be anticarcinogenic, antiobesity and antidiabetic, whereas c-9, t-11-CLA is mainly anti-inflammatory. Although preclinical data support a benefit of CLA supplementation, human clinical findings have yet to show definitive evidence of a positive effect. The purpose of this review is to comprehensively summarize the mechanisms of action and anti-inflammatory properties of dietary CLA supplementation and evaluate the potential uses of CLA in human health and disease.

Modeling mucosal immunity- gut microbiota interactions during Clostridium difficile infection (MUC3P.948)

Clostridium difficile is a facultative pathogen associated with antibiotic-induced infections which result in an exuberant inflammatory response, leading to nosocomial diarrhea, colitis and even death. We have previously reported novel evidence supporting a role of T cells in modulating host responses to C. difficile. Specifically, T cell alteration towards a pro-inflammatory phenotype due to lack of PPARγ resulted in increased disease symptoms and colonic pathology, which correlated with the abrogation of T cell regulatory (Treg) responses and shift towards a Th17-driven cellular response. To better understand the role of T cells during C. difficile infection from initiation through expansion to resolution, we built a computational model of the cellular host response to the bacterium. In line with our experimental findings, the model demonstrates a crucial role of Th17 effector and Treg responses, as well as an important contribution from commensal bacteria populations in the clearance of C. difficile and colonic pathology. Simulation results predict that proper clearance of infection with reduced damage to the epithelium is possible through a shift in the relative populations of Th17 and Treg cell subsets or through an accelerated regrowth of beneficial commensal strains. Our modeling provides novel insights on the mechanisms regulating C. difficile-associated immunopathology and show the path towards safer and more effective therapeutic interventions.

Immune modulatory mechanisms of lanthionine synthetase C-like protein 2 (IRM12P.656)

Lanthionine synthetase C-like protein 2 (LANCL2) has emerged as a novel therapeutic target for metabolic, infectious and immune-mediated diseases. We previously demonstrated that directly targeting LANCL2 through treatment with abscisic acid or 61610 results in efficacious anti-inflammatory responses during DSS-induced colitis however molecular mechanisms underlying this immunomodulatory function remain elusive. Here we report for the first time the use of LANCL2-deficient mice to investigate the mechanism of action and cell specificity of the protein. At the cellular level, bone marrow derived macrophages (BMDM), RAW cells, and gastric epithelial cells express comparable levels of basal LANCL2 mRNA. LPS-mediated inflammation in BMDM increased both mRNA and protein levels of LANCL2 that peaked 6 hours post-challenge and subsequently returned to normal levels after 12 hours. Similarly, DSS-induced colitis induced expression of LANCL2 in the colons of wild-type (WT) mice and correlated with elevated levels of proinflammatory cytokines. Interestingly, the absence of LANCL2 did not cause significant alterations in infiltrating cellular phenotypes however LANCL2-deficiency permitted exaggerated IL17 and IFNγ expression in colonic tissue when compared to WT counterparts at day 7 post-challenge. In conclusion, our findings indicate that LANCL2 is a novel regulator of inflammation that functions predominantly at the molecular level to down-regulate excessive inflammatory responses.

Macrophages modulate bacterial persistence and gastric pathology during Helicobacter pylori infection (INC4P.346)

Based on preliminary data suggesting that macrophages are critical regulators of Helicobacter pylori colonization and gastric pathology, we investigated how macrophage phenotypes shape the outcome of infection and persistence. The loss of PPARγ in the myeloid compartment favors a 5 to 10-fold decrease in bacterial loads at the expense of more severe gastric lesions. PPARγ-deficient macrophages present altered control of transcription factors such as NFκB, which results in a pro-inflammatory phenotype. Stomach lamina propria analyses at weeks 0 to 4 post-infection revealed increased levels of CD11b+ F4/80hi CD64+ CR3CR1+ macrophages in WT mice, while PPARγKO mice failed to expand and maintain such population. Macrophage depletion using clodronate liposomes resulted in a significant reduction of gastric H. pylori in WT mice, thus abrogating the differences in bacterial loads observed between WT and PPARγKO mice. In vitro co-culture of H. pylori with bone marrow derived macrophages showed that either PPARγ loss or pharmacological blockade enhances bactericidal activity, which is associated to significant differential expression of chil1, etv5, iigp1, ptger4, sqle, osm, hspa2 and rptoros levels as revealed by global transcriptome analyses. Hence, macrophages facilitate H. pylori infection by 1) serving as bacterial reservoirs and allowing intracellular replication, and 2) favoring a gastric regulatory response that favors persistence.