T cell epitopes of Per a 10 modulate local-systemic immune responses and airway inflammation by augmenting Th1 and T regulatory cell functions in murine model

NLRP3/GSDMD mediated pyroptosis induces lung inflammation susceptibility in diesel exhaust exposed mouse strains

BACKGROUND

Genetic diversity among species influences the disease severity outcomes linked to air pollution. However, the mechanism responsible for this variability remain elusive and needs further investigation.

OBJECTIVE

To investigate the genetic factors and pathways linked with differential susceptibility in mouse strains associated with diesel exhaust exposure.

METHODS

C57BL/6 and Balb/c mice were exposed to diesel exhaust (DE) for 5 days/week for 30 min/day for 8 weeks. Body weight of mice was recorded every week and airway hyperresponsiveness towards DE exposure was recorded after 24 h of last exposure. Mice were euthanised to collect BALF, blood, lung tissues for immunobiochemical assays, structural integrity and genetic studies.

RESULTS

C57BL/6 mice showed significantly decreased body weight in comparison to Balb/c mice (p < 0.05). Both mouse strains showed lung resistance and damage to elastance upon DE exposure compared to respective controls (p < 0.05) with more pronounced effects in C57BL/6 mice. Lung histology showed increase in bronchiolar infiltration and damage to the wall in C57BL/6 mice (p < 0.05). DE exposure upregulated pro-inflammatory and Th2 cytokine levels in C57BL/6 in comparison to Balb/c mice. C57BL/6 mice showed increase in Caspase-1 and ASC expression confirming activation of downstream pathway. This showed significant activation of inflammasome pathway in C57BL/6 mice with ∼2-fold increase in NLRP3 and elevated IL-1β expression. Gasdermin-D levels were increased in C57BL/6 mice demonstrating induction of pyroptosis that corroborated with IL-1β secretion (p < 0.05). Genetic variability among both species was confirmed with sanger's sequencing suggesting presence of SNPs in 3'UTRs of IL-1β gene influencing expression between mouse strains.

CONCLUSIONS

C57BL/6 mice exhibited increased susceptibility to diesel exhaust in contrast to Balb/c mice via activation of NLRP3-related pyroptosis. Differential susceptibility between strains may be attributed via SNPs in the 3'UTRs of the IL-1β gene.

Cockroach allergy: Understanding complex immune responses to develop novel therapies

Cockroach allergy is associated with the development of asthma. The identification of cockroach allergens, which began in the 1990 s, is an ongoing process that has led to the current listing of 20 official allergen groups in the WHO/IUIS Allergen Nomenclature database. The function and structure of some of these allergens has been determined and define their natural delivery into the environment and their allergenicity. Analysis of antigenic determinants by X-ray crystallography and rational design of site-directed mutagenesis led to the identification of IgE binding sites for the design of molecules with reduced IgE reactivity and T cell modulatory capacity. New developments in recent years include component analyses of B and T cell reactivity and a recent cockroach immunotherapy trial, CRITICAL, that will contribute to understand the immune response to cockroach and to define future directions for cockroach allergy diagnosis and immunotherapy.

Per a 5-derived T-cell peptides modulate NF-kB signalling to ameliorate allergic inflammation systemically in murine model of cockroach allergic hyper-reactivity

Peptide immunotherapy (PIT) represents a safe and efficacious therapeutic regimen with in-consequential side-effects. The present study aims to identify T-cell epitopes of Per a 5 allergen, a delta class GST from Periplaneta americana and investigate effect of peptide treatment in murine model of cockroach allergen-mediated hyper-reactivity. The epitopes (TC-P1, TC-P2, and TC-P3) were identified as promiscuous MHC-II binders by MHC-Pred, ProPred, and IEDB analysis tool. Murine model of cockroach allergic hyper-reactivity was generated in Balb/c mice. A marked reduction in cellular infiltration in lungs (3-fold compared with Non-IT) was observed in T3-IT group as evidenced by total leucocyte count in BALF and histology. Specific IgE levels were reduced 3-fold in T2-IT and T3-IT compared with Non-IT with increase in IgG2a levels. IL-4 and IL-13 were reduced upto 2.5-fold in treatment groups compared with Non-IT group. Splenocytes revealed significant increase in levels of CD4+FoxP3+ T cells in TC-P1 and TC-P2 mice demonstrating a systemic shift towards Tregs. Peptide treatment downregulated NF-kB signalling in lung and enhanced the levels of immune-regulatory molecules α1-antitrypsin and elafin. Our results indicate that TC-P1 and TC-P3 alter Th2 cytokine milieu and antibody isotype ratio to suppress allergic inflammation. PIT modulates local and systemic mechanisms to resolve inflammation and possess potential for treatment in cockroach allergy.

Diesel exhaust exposure in mice induces pulmonary fibrosis by TGF-β/Smad3 signaling pathway

BACKGROUND

Epidemiological studies suggest increased risk of lung cancer associated with diesel exhaust (DE) exposure. However, DE-induced lung fibrosis may lead to cancer and needs investigation.

OBJECTIVES

To study the mechanism involved in the initiation of DE- induced lung fibrosis.

METHODS

C57BL/6 mice were exposed to DE for 30 min/day for 5 days/weeks for 8 weeks. Pulmonary function test was performed to measure lung function. Mice were euthanized to collect BALF, blood, and lung tissue. BALF was used for cell count and cytokine analysis. Lung tissue slides were stained to examine structural integrity. RNA from lung tissue was used for RT-PCR. Immunoblots were performed to study fibrosis and EMT pathway.

RESULTS

Mice exposed to DE increase lung resistance and tissue elastance with decrease in inspiratory capacity (p < 0.05) suggesting lung function impairment. BALF showed significantly increased macrophages, neutrophils and monocytes (p < 0.01). Additionally, there was an increase in inflammation and alveolar wall thickening in lungs (p < 0.01) correlates with cellular infiltration. Macrophages had black soot deposition in lung tissue of DE exposed mice. Lung section staining revealed increase in mucus producing goblet cells for clearance of soot in lung. DE exposed lung showed increased collagen deposition and hydroxyproline residue (p < 0.01). Repetitive exposure of DE in mice lead to tissue remodeling in lung, demonstrated by fibrotic foci and smooth muscles. A significant increase in α-SMA and fibronectin (p < 0.05) in lung indicate progression of pulmonary fibrosis. TGF-β/Smad3 signaling was activated with increase in P-smad3 expression in DE exposed mice. Decreased expression of E-cadherin and increased vimentin (p < 0.05) in lungs of DE exposed mice indicate epithelial to mesenchymal transition.

CONCLUSION

DE exposure to mice induced lung injury and pulmonary fibrosis thereby remodeling tissue. The study demonstrates TGF-β/SMAD3 pathway involvement with an activation of EMT in DE exposed mice.

The allergenic activity and clinical impact of individual IgE-antibody binding molecules from indoor allergen sources

A large number of allergens have been discovered but we know little about their potential to induce inflammation (allergenic activity) and symptoms. Nowadays, the clinical importance of allergens is determined by the frequency and intensity of their IgE antibody binding (allergenicity). This is a rather limited parameter considering the development of experimental allergology in the last 20 years and the criteria that support personalized medicine. Now it is known that some allergens, in addition to their IgE antibody binding properties, can induce inflammation through non IgE mediated pathways, which can increase their allergenic activity. There are several ways to evaluate the allergenic activity, among them the provocation tests, the demonstration of non-IgE mediated pathways of inflammation, case control studies of IgE-binding frequencies, and animal models of respiratory allergy. In this review we have explored the current status of basic and clinical research on allergenic activity of indoor allergens and confirm that, for most of them, this important property has not been investigated. However, during recent years important advances have been made in the field, and we conclude that for at least the following, allergenic activity has been demonstrated: Der p 1, Der p 2, Der p 5 and Blo t 5 from HDMs; Per a 10 from P. americana; Asp f 1, Asp f 2, Asp f 3, Asp f 4 and Asp f 6 from A. fumigatus; Mala s 8 and Mala s 13 from M. sympodialis; Alt a 1 from A. alternata; Pen c 13 from P. chrysogenum; Fel d 1 from cats; Can f 1, Can f 2, Can f 3, Can f 4 and Can f 5 from dogs; Mus m 1 from mice and Bos d 2 from cows. Defining the allergenic activity of other indoor IgE antibody binding molecules is necessary for a precision-medicine-oriented management of allergic diseases.

Recent advances on animal models related to chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) has become an important public health problem in the world. According to reports, COPD ranks fourth in the global cause of death, causing a serious economic burden on society. The pathogenesis of COPD is complex, making it difficult to simulate the pathological changes and clinical features of COPD. Moreover, the COPD animal model has an irreplaceable role in the study of etiology, pathology and treatment. It is worth noting that the risk factors for chronic obstructive pulmonary disease persist, and the economic burden of global chronic obstructive pulmonary disease is expected to continue to increase in the coming decades. Establishing a standardized, a clinically realistic COPD animal model has always been a research direction that scholars are keen on. Therefore, it is essential to establish an economical animal model. The establishment of a suitable animal model can accurately simulate the pathological features of human chronic obstructive pulmonary disease and help to develop effective interventions and treatments in a short period of time. This review integrates the experimental animal species selected in the animal models used in COPD studies. Subsequently, different methods and mechanisms for establishing animal models were summarized according to different modeling factors. Finally, the criteria for evaluating existing animal models are discussed. It is hoped that the summary of this paper will guide the establishment of relevant animal models for future COPD research.

Topical Spilanthol Inhibits MAPK Signaling and Ameliorates Allergic Inflammation in DNCB-Induced Atopic Dermatitis in Mice

Atopic dermatitis (AD) is a recurrent allergic skin disease caused by genetic and environmental factors. Patients with AD may experience immune imbalance, increased levels of mast cells, immunoglobulin (Ig) E and pro-inflammatory factors (Cyclooxygenase, COX-2 and inducible NO synthase, iNOS). While spilanthol (SP) has anti-inflammatory and analgesic activities, its effect on AD remains to be explored. To develop a new means of SP, inflammation-related symptoms of AD were alleviated, and 2,4-dinitrochlorobenzene (DNCB) was used to induce AD-like skin lesions in BALB/c mice. Histopathological analysis was used to examine mast cells and eosinophils infiltration in AD-like skin lesions. The levels of IgE, IgG1 and IgG2a were measured by enzyme-linked immunosorbent assay (ELISA) kits. Western blot was used for analysis of the mitogen-activated protein kinase (MAPK) pathways and COX-2 and iNOS protein expression. Topical SP treatment reduced serum IgE and IgG2a levels and suppressed COX-2 and iNOS expression via blocked mitogen-activated protein kinase (MAPK) pathways in DNCB-induced AD-like lesions. Histopathological examination revealed that SP reduced epidermal thickness and collagen accumulation and inhibited mast cells and eosinophils infiltration into the AD-like lesions skin. These results indicate that SP may protect against AD skin lesions through inhibited MAPK signaling pathways and may diminish the infiltration of inflammatory cells to block allergic inflammation.