Restoration Of Barrier Function Research Articles

The basement membrane in epidermal polarity, stemness, and regeneration.

The epidermis is a specialized epithelium that constitutes the outermost layer of the skin, and it provides a protective barrier against environmental assaults. Primarily consisting of multilayered keratinocytes, the epidermis is continuously renewed by proliferation of stem cells and the differentiation of their progeny, which undergo terminal differentiation as they leave the basal layer and move upward toward the surface, where they die and slough off. Basal keratinocytes rest on a basement membrane at the dermal-epidermal junction that is composed of specific extracellular matrix proteins organized into interactive and mechanically supportive networks. Firm attachment of basal keratinocytes, and their dynamic regulation via focal adhesions and hemidesmosomes, is essential for maintaining major skin processes, such as self-renewal, barrier function, and resistance to physical and chemical stresses. The adhesive integrin receptors expressed by epidermal cells serve structural, signaling, and mechanosensory roles that are critical for epidermal cell anchorage and tissue homeostasis. More specifically, the basement membrane components play key roles in preserving the stem cell pool, and establishing cell polarity cues enabling asymmetric cell divisions, which result in the transition from a proliferative basal cell layer to suprabasal cells committed to terminal differentiation. Finally, through a well-regulated sequence of synthesis and remodeling, the components of the dermal-epidermal junction play an essential role in regeneration of the epidermis during skin healing. Here too, they provide biological and mechanical signals that are essential to the restoration of barrier function.

Development of Radiosterilized Porcine Skin Electrosprayed with Silver Nanoparticles Prevents Infections in Deep Burns.

Extensive burns represent a significant challenge in biomedicine due to the multiple systemic and localized complications resulting from the major skin barrier loss. The functionalization of xenografts with nanostructured antibacterial agents proposes a fast and accessible application to restore barrier function and prevent localized bacterial contamination. Based on this, the objective of this work was to functionalize a xenograft by electrospray deposition with silver nanoparticles (AgNPs) and to evaluate its antibiofilm and cytotoxic effects on human fibroblasts. Initially, AgNPs were synthesized by a green microwave route with sizes of 2.1, 6.8, and 12.2 nm and concentrations of 0.055, 0.167, and 0.500 M, respectively. The AgNPs showed a size relationship directly proportional to the concentration of AgNO3, with a spherical and homogeneous distribution determined by high-resolution transmission electron microscopy. The surface functionalization of radiosterilized porcine skin (RPS) via electrospray deposition with the three AgNP concentrations (0.055, 0.167, and 0.500 M) in the epidermis and the dermis showed a uniform distribution on both surfaces by energy-dispersive X-ray spectroscopy. The antibiofilm assays of clinical multidrug-resistant Pseudomonas aeruginosa showed significant effects at the concentrations of 0.167 and 0.500 M, with a log reduction of 1.3 and 2.6, respectively. Additionally, viability experiments with human dermal fibroblasts (HDF) exposed to AgNPs released from functionalized porcine skin showed favorable tolerance, with retention of viability more significant than 90% for concentrations of 0.05 and 0.167 M after 24 h exposure. Antibacterial activity combined with excellent biocompatibility makes this biomaterial a candidate for antibacterial protection by inhibiting bacterial biofilms in deep burns during early stages of development.

α-Ketoglutarate Restores Intestinal Barrier Function through Promoting Intestinal Stem Cells-Mediated Epithelial Regeneration in Colitis.

This study investigated the preventive effects of α-ketoglutarate (α-KG, in the form of sodium salt) on a Citrobacter rodentium (CR)-induced colitis and explored potential mechanisms. The results demonstrated that CR caused body weight loss and colon length shortening, which were abrogated by the α-KG administration. The colon length of mice in the α-KG plus CR group was significantly higher than that of mice in the CR group (6.9 ± 0.59 (mean ± SD) vs 6.1 ± 0.55; P < 0.05). This beneficial effect was associated with regulating endoplasmic reticulum (ER) stress signaling. In addition, small intestinal organoids generated from intestinal crypts of mice were exposed to α-KG in the presence of TNF-α or IWR-1 to assess stem cell activity in vitro. The results demonstrated that TNF-α exposure decreased the viability of organoids and impaired barrier function by suppressing Wnt signaling, which was abolished by α-KG. Interestingly, the protective effect of α-KG on intestinal barrier function was abrogated by the inhibitor of Wnt signaling in the intestinal organoids. Taken together, α-KG restored barrier function by regulating ER stress and activating Wnt/β-catenin-medicated intestinal stem cell proliferation and differentiation.

Therapeutic material basis and underling mechanisms of Shaoyao Decoction-exerted alleviation effects of colitis based on GPX4-regulated ferroptosis in epithelial cells

BackgroundShaoyao Decoction (SYD) is a canonical herbal medicine prescription formulated by Liu Wan-Su in AD 1186. SYD has been widely used to treat inflammatory bowel disease by clearing heat and damp, removing stasis toxin in the intestine; however, the precise mechanisms and therapeutic material basis remain largely unclear. In the present study, we measured the effects of SYD on colitis symptom, epithelial barrier function, epithelial ferroptosis, colonic protein and mRNA expression of glutathione peroxidase 4 (GPX4) in colitis model, and determined whether SYD restored barrier loss in colitis by modulation of GPX4-regulated ferroptosis pathway.MethodsColitis was established by infusion with 1 mL 2,4,6-trinitrobenzene sulfonic acid (TNBS) dissolved in ethanol (40% v/v) in rats at a 125 mg/kg dose. Ferroptosis in epithelial cells was determined by flow cytometer. GPX4 promoter-firefly luciferase fusion construct was transfected to Caco-2 cell to determine GPX4 transcription. MS analysis was used to identified ingredients in SYD.ResultsDifferent doses of SYD significantly alleviated colitis, decreased ferroptosis in epithelial cells, knockout of GPX4 significantly reversed SYD-induced alleviation effects on colitis, restoration of epithelial barrier function, and epithelial ferroptosis. Wogonoside, wogonin, palmatine, paeoniflorin and liquiritin were identified as active ingredients of SYD-exerted alleviation effects of colitis based on GPX4 agonistic transcription.ConclusionSYD alleviated chemically induced colitis by activation of GPX4, inhibition of ferroptosis in epithelial cells and further restoration of barrier function. Wogonoside, wogonin, palmatine, paeoniflorin and liquiritin were identified as the key therapeutic material basis of SYD-exerted anti-colitis effects. The findings provide a scientific basis for the therapeutic effect of SYD on colitis.

438 An efficacious cosmetic formulation for managing barrier damage following mild-moderate skin disruption

Stratum Corneum is a compacted layer of corneocytes embedded in a lipid matrix, that forms a semipermeable barrier on the surface of the skin. Despite its seemingly delicate thinness of 10-30 μm, the Stratum Corneum [SC] plays a vital role in serving as a first line of defense to protect against external environmental stressors. Even minor disruption to this layer can lead to a loss of barrier integrity that manifest as an increase in Transepidermal Water Loss [TEWL]. Many common cosmetic dermatological treatments can inflict varying degrees of short-term damage to the SC. In order to help the SC maintain and restore barrier function, a topical serum was developed containing a combination of Macrocystis pyrifera ferment and other ingredients. This preparation is shown in clinical studies to strengthen the barrier of intact skin, making the barrier not only more robust against mild skin disruption but also to enhance barrier recovery even after the intense effects of cosmetic dermatological treatments such as peels and laser treatment. Moreover, this barrier repair serum is shown to be more effective at helping the barrier recover than a conventional moisturizing lotion during post-treatment recovery. Through a series of in vivo evaluations, this serum is shown to reduce TEWL of intact skin, to help build back SC quality, to reduce the immediate barrier disruption caused by cosmetic glycolic peel or laser procedures and to help SC barrier recovery post-procedure. To build upon the in vivo findings, immunohistochemical analysis of ex vivo skin demonstrated that 70 % glycolic acid acutely disrupts the tight junction protein, claudin-1 and filaggrin. Ex vivo skin pretreated with the serum exhibited intact claudin-1 morphology and showed a greater signal intensity of both claudin-1 and filaggrin compared to ex vivo skin treated with glycolic acid alone, suggesting that the serum may contribute to accelerated barrier recovery.

Role of CB1 receptors in the acute regulation of small intestinal permeability: effects of high-fat diet.

The endocannabinoid system of the gastrointestinal tract is involved in the control of intestinal barrier function. Whether the cannabinoid 1 (CB1) receptor is expressed on the intestinal epithelium and acutely regulates barrier function has not been determined. Here, we tested the hypothesis that ligands of the CB1 receptor acutely modulate small intestinal permeability and that this is associated with altered distribution of tight junction proteins. We examined the acute effects of CB1 receptor ligands on small intestinal permeability both in chow-fed and 2-wk high-fat diet (HFD)-fed mice using Ussing chambers. We assessed the distribution of CB1 receptor and tight junction proteins using immunofluorescence and the expression of CB1 receptor using PCR. A low level of CB1 expression was found on the intestinal epithelium. CB1 receptor was highly expressed on enteric nerves in the lamina propria. Neither the CB1/CB2 agonist CP55,940 nor the CB1 neutral antagonist AM6545 altered the flux of 4kDa FITC dextran (FD4) across the jejunum or ileum of chow-fed mice. Remarkably, both CP55,940 and AM6545 reduced FD4 flux across the jejunum and ileum in HFD-fed mice that have elevated baseline intestinal permeability. These effects were absent in CB1 knockout mice. CP55,940 reduced the expression of claudin-2, whereas AM6545 had little effect on claudin-2 expression. Neither ligand altered the expression of ZO-1. Our data suggest that CB1 receptor on the intestinal epithelium regulates tight junction protein expression and restores barrier function when it is increased following exposure to a HFD for 2 wk.NEW & NOTEWORTHY The endocannabinoid system of the gastrointestinal tract regulates homeostasis by acting as brake on motility and secretion. Here we show that when exposed to a high fat diet, intestinal permeability is increased and activation of the CB1 receptor on the intestinal epithelium restores barrier function. This work further highlights the role of the endocannabinoid system in regulating intestinal homeostasis when it is perturbed.

BATF3 Protects Against Metabolic Syndrome and Maintains Intestinal Epithelial Homeostasis.

The intestinal immune system and microbiota are emerging as important contributors to the development of metabolic syndrome, but the role of intestinal dendritic cells (DCs) in this context is incompletely understood. BATF3 is a transcription factor essential in the development of mucosal conventional DCs type 1 (cDC1). We show that Batf3-/- mice developed metabolic syndrome and have altered localization of tight junction proteins in intestinal epithelial cells leading to increased intestinal permeability. Treatment with the glycolysis inhibitor 2-deoxy-D-glucose reduced intestinal inflammation and restored barrier function in obese Batf3-/- mice. High-fat diet further enhanced the metabolic phenotype and susceptibility to dextran sulfate sodium colitis in Batf3-/- mice. Antibiotic treatment of Batf3-/- mice prevented metabolic syndrome and impaired intestinal barrier function. Batf3-/- mice have altered IgA-coating of fecal bacteria and displayed microbial dysbiosis marked by decreased obesity protective Akkermansia muciniphila, and Bifidobacterium. Thus, BATF3 protects against metabolic syndrome and preserves intestinal epithelial barrier by maintaining beneficial microbiota.

Fibrous palygorskite clays as versatile nanocarriers for skin delivery of tea tree oils in efficient acne therapy

This paper presents a facile approach to develop palygorskite (Pal), a fibrous clay mineral, as a delivery system of tea tree oil (TTO) for topical acne therapy. The obtained TTO-Pal composite showed an efficient loading of TTO (27.4%) with a selective accumulation of terpine-4-ol and 1,8-cineole (two major antimicrobial TTO constituents), sustained release of TTO at skin physiological conditions (pH5.4, 32 °C) and superior skin sebum (2.2 g/g) absorbability. In vitro toxicological assessments showed that the Pal incorporation strategy significantly reduced the acute contact toxicity of TTO. The antimicrobial results revealed a preferable bacteriostatic effect for the TTO-Pal system towards opportunistic dermal pathogens (Escherichia coli, Staphylococcus aureus and Propionibacterium acnes) over the beneficial bacterium (Staphylococcus epidermis). Moreover, TTO-Pal based formulations exhibited pronounced clinical therapeutic efficacy in treating facial acne by rapidly reducing inflamed lesions, modulating skin sebum overproduction and restoring barrier function. This is the first report of using fibrous clay as a biocompatible nanocarrier system for topical delivery of essential oils in efficient management of facial acne with both in vitro and in vivo evidences, which may open perspectives for fibrous clay-drug delivery system in topical application and expand the high added value development of this mineral resource in the advanced healthcare fields.

1392-P: Gut Microbiota Contributes to the Beneficial Metabolic Effects of Gelesis Hydrogel Technology

Gelesis' Oral superabsorbent hydrogels (OSH) are crosslinked cellulose-based materials that expand upon hydration in the gastrointestinal tract and are engineered to mimic the mechanical properties of masticated vegetables. One OSH prototype, denoted Gel-B, was tested in both preventative and treatment settings in murine models of diet-induced obesity. Gel-B administration blunted weight gain, reversed gut atrophy, improved metabolic parameters (glucose and insulin tolerance tests; GTT and ITT) and restored barrier function. Here, we investigated the functional role of the gut microbiome to partially explain these protective metabolic effects. Metabolic disease was induced in both Donor (n=24) and Recipient (n=24) C57BL6/J mice via consumption of a high fat and high cholesterol/carbohydrate (HFHCC) diet for weeks (wks) . Donor mice continued on HFHCC or were treated with HFHCC+Gel-B (2 or 4%) for an additional 6 wks. After 2 wks treatment, Donor fecal samples were processed every other day for intestinal microbiota transplantation (IMT) . Recipient mice continued HFHCC and received IMT derived from either HFHCC or Gel-B (2 or 4%) treated Donors via gavage every other day for 4 wks. At 4 wks, the HFHCC-corrected % body weight difference in Recipients was -10.8% and -9.6% for the 2% Gel-B-derived IMT (p=0.02) , and 4% Gel-B-derived IMT (p= 0.02) respectively. Glucose excursions, AUC 0-2h from GTT, were significantly reduced in both Recipient groups (p=0.for both 2% and 4% Gel-B-derived IMT) . The AUC 0-2h from ITT were significantly increased in the 4% Gel-B-derived IMT Recipients (p=0.04) and trended for the 2% Gel-B-derived IMT group (p=0.13) . The present study demonstrates for the first time that IMT from Gel-B treated Donors confers beneficial metabolic effects in HFHCC treated mice. Future experiments will define Gel-B associated microbiota and examine engraftment and durability of IMT. Disclosure A.Silvestri: None. A.Gil-gomez: None. E.Chiquette: Employee; Gelesis. C.Demitri: Stock/Shareholder; Gelesis. B.W.Jones: Employee; Gelesis. A.Sannino: None. M.Rescigno: Research Support; Gelesis.

P2X7 inhibition prevents mitochondrial stress caused by alcohol and e‐cigarette exposure in primary vascular endothelial cells and restores barrier function

Studies in both human and animal models demonstrated that chronic alcohol/e‐cigarette (e‐Cig) exposure affects mitochondrial function and impairs barrier function in brain microvascular endothelial cells (BMVEC). Identification of the signaling pathways by which chronic alcohol/e‐Cig exposure induces mitochondrial damage in BMVEC is vital for protection of the blood‐brain barrier. We treated primary human BMVEC with ethanol (100 mM) or e‐Cig conditioned medium and showed reduced mitochondrial oxidative phosphorylation (OXPHOS) analyzed by a Seahorse analyzer. Chronic alcohol/e‐Cig treatment significantly reduced the expression of mitochondrial OXPHOS proteins and pyruvate dehydrogenase (a vital enzyme in the TCA cycle) detected by western blot. We observed the cytosolic escape of ATP and its extracellular release due to the disruption of mitochondrial membrane potential after alcohol or e‐Cig treatment of BMVEC. Further, alcohol or e‐Cig treatment resulted in an elevated purinergic receptor (P2X7) and TRPV1 channel expression by qPCR in primary BMVEC. We showed a protective role of the P2X7r antagonist which restored the mitochondrial oxidative phosphorylation levels and prevented ATP release. In summary, we identified potential common pathways of mitochondrial injury caused by alcohol and e‐Cig which allow new protective interventions. We are further investigating the potential link between P2X7 regulatory pathways and mitochondrial health.

Mechanisms of mucosal healing: treating inflammatory bowel disease without immunosuppression?

Almost all currently available treatments for inflammatory bowel disease (IBD) act by inhibiting inflammation, often blocking specific inflammatory molecules. However, given the infectious and neoplastic disease burden associated with chronic immunosuppressive therapy, the goal of attaining mucosal healing without immunosuppression is attractive. The absence of treatments that directly promote mucosal healing and regeneration in IBD could be linked to the lack of understanding of the underlying pathways. The range of potential strategies to achieve mucosal healing is diverse. However, the targeting of regenerative mechanisms has not yet been achieved for IBD. Stem cells provide hope as a regenerative treatment and are used in limited clinical situations. Growth factors are available for the treatment of short bowel syndrome but have not yet been applied in IBD. The therapeutic application of organoid culture and stem cell therapy to generate new intestinal tissue could provide a novel mechanism to restore barrier function in IBD. Furthermore, blocking key effectors of barrier dysfunction (such as MLCK or damage-associated molecular pattern molecules) has shown promise in experimental IBD. Here, we review the diversity of molecular targets available to directly promote mucosal healing, experimental models to identify new potential pathways and some of the anticipated potential therapies for IBD.

90 Efficacy of Porcine Skin Xenotransplants Indistinguishable from Allograft in First-in-human Clinical Evaluation

IntroductionHuman cadaver allograft (HCA) is the current standard of care for temporary wound closure of large burns, but a critical need for high-quality alternatives exists. Porcine skin shares many similarities with human skin, and hyperacute rejection is prevented via a single genetic modification. Like human skin, non-terminally sterilized porcine skin contains viable dermal and epidermal cells and intact vasculature that enables restoration of barrier function. These characteristics are distinct from those of traditional, terminally sterilized “xenografts” and may offer greater therapeutic capability. We report here key efficacy outcomes specific to severe burn care from a first-in-human clinical trial to assess the capability of genetically engineered porcine skin xenotransplants to provide temporary wound closure for severe and extensive deep-partial and full-thickness burn wounds, compared to HCA.MethodsSplit-thickness skin containing epidermal and dermal layers was harvested from Designated Pathogen Free, GalT-KO, porcine donors, cGMP processed to achieve USP< 71 > sterility and cryopreserved to retain >70% cell viability. These were transplanted side by side with HCA on debrided full-thickness burn wounds in six human subjects. Temporary wound closure, incidence of complete wound closure following autografting, and quality of healing, including scarring, contour, and feel of healed skin, normalization of skin markings or pigmentation, were independently assessed.ResultsAcross all patients and assessment time points, adherence, vascularity, and overall appearance were indistinguishable between porcine skin xenotransplants and HCA control. After surgical removal, wound beds treated with each type of dressing were perfused and otherwise appeared equivalent and clinically suitable for autografting. Long-term outcomes were comparable between wound sites treated with porcine skin or HCA with no discernable differences in scarring or cosmesis.ConclusionsSkin xenotransplants effectively provided temporary wound closure and restoration of barrier function via intact native vasculature, active cells, decreased antigenicity, and high-quality tissue architecture unimpacted by cryopreservation and thawing. These results show clinical promise as an interchangeable alternative to HCA in the treatment of severe burns. Expanded clinical evaluation is ongoing.

Microphysiological model of renal cell carcinoma to inform anti-angiogenic therapy

Renal cell carcinomas are common genitourinary tumors characterized by high vascularization and strong reliance on glycolysis. Despite the many available therapies for renal cell carcinomas, first-line targeted therapies, such as cabozantinib, and durable reaponses are seen in only a small percentage of patients. Yet, little is known about the mechanisms that drive response (or lack thereof). This dearth of knowledge can be explained by the dynamic and complex microenvironment of renal carcinoma, which remains challenging to recapitulate in vitro. Here, we present a microphysiological model of renal cell carcinoma, including a tubular blood vessel model of induced pluripotent stem cell-derived endothelial cells and an adjacent 3D carcinoma model. Our model recapitulated hypoxia, glycolic metabolism, and sprouting angiogenesis. Using our model, we showed that cabozantinib altered cancer cell metabolism and decreased sprouting angiogenesis but did not restore barrier function. This microphysiological model could be helpful to elucidate, through multiple endpoints, the contributions of the relevant environmental components in eliciting a functional response or resistance to therapy in renal cell carcinoma.

The anti-inflammatory properties of ethyl acetate fraction in ethanol extract from Sarcodia suiae sp. alleviates atopic dermatitis-like lesion in mice.

Atopic dermatitis (AD) is a chronic inflammatory and pruritic disease; it can be treated by inhibiting inflammation. Sarcodia suiae sp. is an edible, artificially cultivable red algae with multiple bioactivities. We assessed the anti-inflammatory activity of the ethyl acetate fraction of S. suiae sp. ethanol extract (PD1) on 1-chloro-2,4-dinitrochlorobenzene (DNCB)-induced AD-like lesions. Results show that PD1 alleviated symptoms and significantly decreased clinical dermatitis score. PD1 inhibited serum immunoglobulin E expression and alleviated swelling in the spleen and subiliac lymph nodes. In skin tissues, PD1 alleviated aberrant hyperplasia, decreased epidermal thickness, and decreased the accumulation of mast cells. PD1 mediated the recovery of skin barrier-related proteins, such as claudin-1 and filaggrin. Our study demonstrated that PD1 has anti-inflammatory effects, alleviates AD symptoms, inhibits inflammatory responses in skin tissues, and restores barrier function in DNCB-induced AD mice. These findings reveal that S. suiae sp. extract provides an alternative protective option against AD.

Contribution of protein-protein interactions to the endothelial-barrier-stabilizing function of KRIT1.

ABSTRACTKrev-interaction trapped protein 1 (KRIT1) is an endothelial scaffold protein that promotes adherens junction (AJ) stability. The precise mechanism by which KRIT1 promotes barrier stabilization is unclear. We tested the ability of a panel of KRIT1 constructs containing mutations that inhibit Rap1 binding, ICAP1α binding, disrupt KRIT1's phosphotyrosine-binding (PTB) domain, or direct KRIT1 to the plasma membrane, either alone or in combination, to restore barrier function in KRIT1-deficient endothelial cells. We found that ablating the 192NPAY195 motif or disrupting the PTB domain was sufficient to restore AJ protein localization and barrier function to control levels, irrespective of the junctional localization of KRIT1 or Rap1 binding. The ability of our KRIT1 constructs to rescue AJ and barrier function in KRIT1-depleted endothelial cells correlated with decreased β1 integrin activity and maintenance of cortical actin fibers. Taken together, our findings indicate that Rap1 binding, ICAP1α binding and junctional localization are not required for the ability of KRIT1 to stabilize endothelial contacts, and suggest that the ability of KRIT1 to limit integrin activity could be involved in barrier stabilization.

Gardenia jasminoides extract ameliorates DfE-induced atopic dermatitis in mice through restoration of barrier function and T-helper 2-mediated immune response.

Atopic dermatitis (AD) leads to skin barrier abnormalities and immune dysfunction. As the topical steroids commonly used to treat AD have side effects from long-term use, research into safer treatments for AD is greatly needed. The medicinal herb Gardenia jasminoides improves AD symptoms via skin barrier activation and T helper 2-mediated immune response regulation. Crocin, a bioactive component within the extract, is dispensible for its restorative effects. As such, this work explored the effects of Gardenia jasminoides extract without crocin (GjexCr) on AD symptoms in a DfE-induced AD model in 6-week-old male NC/Nga mice (25.0±0.25g, n=10 each, 6 groups). Using histological and behavioral assays, the effects of GjexCr on dermatitis scores, scratching behavior, skin barrier activation, and serum levels of IgE, chemokines, and cytokines were analyzed. In addition, the major components from the GjexCr extract were analyzed by high-performance liquid chromatography and validated in the AD model. GjexCr reduced ear thickness due to hyperkeratosis, dermal thickening, and scratching behavior and restored dermatitis scores in AD-induced mice. GjexCr administration also decreased inflammation and mast cell infiltration, as well as modulated skin barrier recovery by upregulating the production of epidermal proteins. Moreover, GjexCr administration attenuated imbalanced immune responses. Furthermore, geniposide, the main component of GjexCr, improved AD symptoms in DfE-treated NC/Nga mice. Thus, GjexCr could be a suitable treatment for protecting the skin barrier in AD-like skin lesions and a potential therapy for AD.

Research-Based Product Innovation to Address Critical Unmet Needs of Patients with Inflammatory Bowel Diseases.

Despite progress in recent decades, patients with inflammatory bowel diseases face many critical unmet needs, demonstrating the limitations of available treatment options. Addressing these unmet needs will require interventions targeting multiple aspects of inflammatory bowel disease pathology, including disease drivers that are not targeted by available therapies. The vast majority of late-stage investigational therapies also focus primarily on a narrow range of fundamental mechanisms. Thus, there is a pressing need to advance to clinical stage differentiated investigational therapies directly targeting a broader range of key mechanistic drivers of inflammatory bowel diseases. In addition, innovations are critically needed to enable treatments to be tailored to the specific underlying abnormal biological pathways of patients; interventions with improved safety profiles; biomarkers to develop prognostic, predictive, and monitoring tests; novel devices for nonpharmacological approaches such as minimally invasive monitoring; and digital health technologies. To address these needs, the Crohn’s & Colitis Foundation launched IBD Ventures, a venture philanthropy–funding mechanism, and IBD Innovate®, an innovative, product-focused scientific conference. This special IBD Innovate® supplement is a collection of articles reflecting the diverse and exciting research and development that is currently ongoing in the inflammatory bowel disease field to deliver innovative and differentiated products addressing critical unmet needs of patients. Here, we highlight the pipeline of new product opportunities currently advancing at the preclinical and early clinical development stages. We categorize and describe novel and differentiated potential product opportunities based on their potential to address the following critical unmet patient needs: (1) biomarkers for prognosis of disease course and prediction/monitoring of treatment response; (2) restoration of eubiosis; (3) restoration of barrier function and mucosal healing; (4) more effective and safer anti-inflammatories; (5) neuromodulatory and behavioral therapies; (6) management of disease complications; and (7) targeted drug delivery.

Nuclear IL-33 as a growth and survival agent within basal cells.

IL-33 is a well-studied cytokine that resides normally within nuclei but can be released by cell damage or stress to then signal via a single receptor widely expressed on immune cells to promote host resistance and type 2 allergic immunity. In this issue of the JCI, Wu et al. used a well-established model of mouse Sendai viral infection to show that IL-33 was induced in distal lung airway epithelium, specifically in cell-cycling basal cells. IL-33 induced cell-cycling basal cells to expand and migrate into the alveolar compartment, presumably to restore barrier function. However, restoring barrier function with airway-derived cells may also result in persistent alveolar metaplasia. Surprisingly, nuclear IL-33 in this system acted cell autonomously, independently of release and conventional ST2 (IL1RL1) receptor signaling. The findings uncover a signaling role for nuclear IL-33 in viral activation of mouse basal cells and add to the well-known "alarmin" function of IL-33.

106 Dysfunctional mTORC2 signalling as potential risk factor for inflammatory skin diseases

The aim of the presented study was to identify regulators and effectors by which the skin orchestrates balanced defense while promoting regenerative responses to maintain skin barrier integrity and function during life. The mTOR (mammalian target of rapamycin) signalling pathway is essential for cell growth and metabolism. Mutations altering mTOR signalling have been implicated in diabetes, cancer as well as skin diseases. Here we unraveled a specific role of mTORC2 signalling in epidermal barrier formation. Epidermal mTORC2 signalling was disrupted by deleting Rictor, encoding an essential subunit of mTORC2 in mouse epidermis (RicEKO). Epidermal structure and barrier function were investigated by a combination of gene expression, biochemical, morphological and functional analysis in RicEKO and control mice. RicEKO newborns displayed an ichthyosis-like phenotype characterized by dysregulated epidermal de novo lipid synthesis, altered lipid lamellae structure, and aberrant filaggrin processing. Impaired epidermal function in RicEKO mice was demonstrated by increased transepidermal water loss, enhanced corneocyte fragility, perturbed immune cell composition, an exaggerated percutaneous immune response, and an enhanced type 2 immune signature in the skin. Restoration of Akt-Ser473 phosphorylation in mTORC2-deficient keratinocytes by expression of constitutive Akt rescued filaggrin processing. Our findings reveal a critical metabolic signalling relay of barrier formation where epidermal mTORC2 activity controls filaggrin processing and de novo epidermal lipid synthesis during cornification. mTORC2-regulated pathways are druggable and could serve as potential novel therapeutic targets to restore barrier function in inflammatory skin diseases.

The Role of the Wnt Pathway in VEGF/Anti-VEGF-Dependent Control of the Endothelial Cell Barrier.

PurposeInvestigate the contribution of the Wnt pathway to vascular endothelial growth factor (VEGF)/anti-VEGF-mediated control of endothelial cell permeability.MethodsHigh glucose-treated primary human retinal endothelial cells (HRECs) were exposed to either VEGF, or VEGF and then anti-VEGF. Changes in gene expression were assayed by RNAseq and qRT-PCR. Permeability was monitored by electrical cell-substrate impedance sensing (ECIS). Approaches to activate the Wnt pathway included treatment with LiCl and overexpression of constitutively activated β-catenin. β-catenin-dependent transcriptional activity was monitored in HRECs stably expressing a TCF/LEF-driven reporter.ResultsVEGF/anti-VEGF altered expression of genes encoding many members of the Wnt pathway. A subset of these genes was regulated in a way that is likely to contribute to control of the endothelial cell barrier. Namely, the VEGF-induced alteration of expression of such genes was reversed by anti-VEGF, and such adjustments occurred at times corresponding to changes in barrier function. While pharmacological and molecular approaches to activate the Wnt pathway had no effect on basal permeability, they suppressed VEGF-induced relaxation. Furthermore, anti-VEGF-mediated restoration of barrier function was unaffected by activation of the Wnt pathway.ConclusionsVEGF/anti-VEGF engages multiple members of the Wnt pathway, and activating this pathway enforces the endothelial barrier by attenuating VEGF-induced relaxation. These data suggest that FDA-approved agents such as LiCl may be an adjuvant to anti-VEGF therapy for patients afflicted with blinding conditions including diabetic retinopathy.