Annexin-A1-Derived Peptide Ac2-26 Suppresses Allergic Airway Inflammation and Remodelling in Mice

Development of an Inflamed High Throughput Stem-cell-based Gut Epithelium Model to Assess the Impact of Annexin A1

OBJECTIVE AND DESIGN

Annexin A1 (ANXA1) plays a role in maintaining intestinal hemostasis, especially following mucosal inflammation. The published data about ANXA1 was derived from experimental animal models where there is an overlapping between epithelial and immune cells. There is no in vitro gut epithelial model that can assess the direct effect of ANXA1 on the gut epithelium.

METHODS

We developed high-throughput stem-cell-based murine epithelial cells and bacterial lipopolysaccharides (LPS) were used to induce inflammation. The impact of ANXA1 and its functional part (Ac2-26) was evaluated in the inflamed model. Intestinal integrity was assessed by the transepithelial electrical resistance (TEER), and FITC-Dextran permeability. Epithelial junction proteins were assessed using confocal microscopy and RT-qPCR. Inflammatory cytokines were evaluated by RT-qPCR and ELISA.

RESULTS

LPS challenge mediated a damage in the epithelial cells as shown by a drop in the TEER and an increase in FITC-dextran permeability; reduced the expression of epithelial junctional proteins (Occludin, ZO-1, and Cadherin) and increased the expression of the gut leaky protein, Claudin - 2. ANXA1 and Ac2-26 treatment reduced the previous damaging effects. In addition, ANXA1 and Ac2-26 inhibited the inflammatory responses mediated by the LPS and increased the transcription of the anti-inflammatory cytokine, IL-10.

CONCLUSION

ANXA1 and Ac2-26 directly protect the epithelial integrity by affecting the expression of epithelial junction and inflammatory markers. The inflamed gut model is a reliable tool to study intestinal inflammatory diseases, and to evaluate the efficacy of potential anti-inflammatory drugs and the screening of new drugs that could be candidates for inflammatory bowel disease.

Peptidomics insights: neutrophil extracellular traps (NETs) related to the chronic subdural hemorrhage

Chronic subdural hemorrhage (CSDH) refers to a hematoma with an envelope between the dura mater and the arachnoid membrane and is more common among the elderly. It was reported that the dura mater, which is highly vascularized with capillary beds, precapillary arterioles and postcapillary venules play an important role in the protection of the central nervous system (CNS). Numerous evidences suggests that peptides play an important role in neuroprotection of CNS. However, whether dura mater derived endogenous peptides participate in the pathogenesis of CSDH remains undetermined. In the current study, the peptidomic profiles were performed in human dura of CSDH (three patients) and the relative control group (three non-CSDH samples) by LC-MS (liquid chromatography-mass spectrometry). The results suggested that a total of 569 peptides were differentially expressed in the dura matter of CSDH compared with relative controls, including 217 up-regulated peptides and 352 down-regulated peptides. Gene Ontology (GO) analysis demonstrated that the precursor proteins of those differentially expressed peptides were involved in the various biological processes. Interestingly, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis suggested that NETs participated in the pathogenies of CSDH. Further investigate showed that H3Cit was significantly elevated in the dural and hematoma membranes of patients with CSDH compared to patients without CSDH. Taken together, our results showed the differentially expressed peptides in human dura mater of CSDH and demonstrated that NETs formation in the dural and hematoma membranes might be involved in the pathogenesis of CSDH. It is worth noting that pharmacological inhibition of NETs may have potential therapeutic implications for CSDH.

Cholesterol Exacerbates the Pathophysiology of Non-Alcoholic Steatohepatitis by Upregulating Hypoxia-Inducible Factor 1 and Modulating Microcirculatory Dysfunction

Cholesterol is a pivotal lipotoxic molecule that contributes to the progression of Non-Alcoholic Steatohepatitis NASH). Additionally, microcirculatory changes are critical components of Non-Alcoholic Fatty Liver Disease (NAFLD) pathogenesis. This study aimed to investigate the role of cholesterol as an insult that modulates microcirculatory damage in NAFLD and the underlying mechanisms. The experimental model was established in male C57BL/6 mice fed a high-fat high-carbohydrate (HFHC) diet for 39 weeks. Between weeks 31-39, 2% cholesterol was added to the HFHC diet in a subgroup of mice. Leukocyte recruitment and hepatic stellate cells (HSC) activation in microcirculation were assessed using intravital microscopy. The hepatic microvascular blood flow (HMBF) was measured using laser speckle flowmetry. High cholesterol levels exacerbated hepatomegaly, hepatic steatosis, inflammation, fibrosis, and leukocyte recruitment compared to the HFHC group. In addition, cholesterol decreased the HMBF-cholesterol-induced activation of HSC and increased HIF1A expression in the liver. Furthermore, cholesterol promoted a pro-inflammatory cytokine profile with a Th1-type immune response (IFN-γ/IL-4). These findings suggest cholesterol exacerbates NAFLD progression through microcirculatory dysfunction and HIF1A upregulation through hypoxia and inflammation. This study highlights the importance of cholesterol-induced lipotoxicity, which causes microcirculatory dysfunction associated with NAFLD pathology, thus reinforcing the potential of lipotoxicity and microcirculation as therapeutic targets for NAFLD.

Annexin A12-26 hydrogel improves healing properties in an experimental skin lesion after induction of type 1 diabetes

Diabetes mellitus (DM) is characterized by metabolic alterations that involve defects in the secretion and/or action of insulin, being responsible for several complications, such as impaired healing. Studies from our research group have shown that annexin A1 protein (AnxA1) is involved in the regulation of inflammation and cell proliferation. In light of these findings, we have developed a new technology and evaluated its effect on a wound healing in vivo model using type 1 diabetes (T1DM)-induced mice. We formulated a hydrogel containing AnxA12-26 using defined parameters such as organoleptic characteristics, pH, UV-vis spectroscopy and cytotoxicity assay. UV-vis spectroscopy confirmed the presence of the associated AnxA12-26 peptide in the three-dimensional hydrogel matrix, while the in vitro cytotoxicity assay showed excellent biocompatibility. Mice showed increased blood glucose levels, confirming the efficacy of streptozotocin (STZ) to induce T1DM. Treatment with AnxA12-26 hydrogel showed to improve diabetic wound healing, defined as complete re-epithelialization and tissue remodeling, with reduction of inflammatory infiltrate in diabetic animals. We envisage that the AnxA12-26 hydrogel, with its innovative composition and formulation be efficient on improving diabetic healing and contributing on the expansion of the therapeutic arsenal to treat diabetic wounds, at a viable cost.

Resolution Pharmacology: Focus on Pro-Resolving Annexin A1 and Lipid Mediators for Therapeutic Innovation in Inflammation

Chronic diseases that affect our society are made more complex by comorbidities and are poorly managed by the current pharmacology. While all present inflammatory etiopathogeneses, there is an unmet need for better clinical management of these diseases and their multiple symptoms. We discuss here an innovative approach based on the biology of the resolution of inflammation. Studying endogenous pro-resolving peptide and lipid mediators, how they are formed, and which target they interact with, can offer innovative options through augmenting the expression or function of pro-resolving pathways or mimicking their actions with novel targeted molecules. In all cases, resolution offers innovation for the treatment of the primary cause of a given disease and/or for the management of its comorbidities, ultimately improving patient quality of life. By implementing resolution pharmacology, we harness the whole physiology of inflammation, with the potential to bring a marked change in the management of inflammatory conditions.

Therapeutic potential for targeting Annexin A1 in fibrotic diseases

Annexin A1, a well-known endogenous anti-inflammatory mediator, plays a critical role in a variety of pathological processes. Fibrosis is described by a failure of tissue regeneration and contributes to the development of many diseases. Accumulating evidence supports that Annexin A1 participates in the progression of tissue fibrosis. However, the fundamental mechanisms by which Annexin A1 regulates fibrosis remain elusive, and even the functions of Annexin A1 in fibrotic diseases are still paradoxical. This review focuses on the roles of Annexin A1 in the development of fibrosis of lung, liver, heart, and other tissues, with emphasis on the therapy potential of Annexin A1 in fibrosis, and presents future research interests and directions in fibrotic diseases.