Function-specific IL-17A and dexamethasone interactions in primary human airway epithelial cells.

Asthmatics have elevated levels of IL-17A compared to healthy controls. IL-17A is likely to contribute to reduced corticosteroid sensitivity of human airway epithelium. Here, we aimed to investigate the mechanistic underpinnings of this reduced sensitivity in more detail. Differentiated primary human airway epithelial cells (hAECs) were exposed to IL-17A in the absence or presence of dexamethasone. Cells were then collected for RNA sequencing analysis or used for barrier function experiments. Mucus was collected for volume measurement and basal medium for cytokine analysis. 2861 genes were differentially expressed by IL-17A (Padj < 0.05), of which the majority was not sensitive to dexamethasone (< 50% inhibition). IL-17A did inhibit canonical corticosteroid genes, such as HSD11B2 and FKBP5 (p < 0.05). Inflammatory and goblet cell metaplasia markers, cytokine secretion and mucus production were all induced by IL-17A, and these effects were not prevented by dexamethasone. Dexamethasone did reverse IL-17A-stimulated epithelial barrier disruption, and this was associated with gene expression changes related to cilia function and development. We conclude that IL-17A induces function-specific corticosteroid-insensitivity. Whereas inflammatory response genes and mucus production in primary hAECs in response to IL-17A were corticosteroid-insensitive, corticosteroids were able to reverse IL-17A-induced epithelial barrier disruption.

Pharmacological Rationale for Targeting IL-17 in Asthma.

Asthma is a respiratory disease that currently affects around 300 million people worldwide and is defined by coughing, shortness of breath, wheezing, mucus overproduction, chest tightness, and expiratory airflow limitation. Increased levels of interleukin 17 (IL-17) have been observed in sputum, nasal and bronchial biopsies, and serum of patients with asthma compared to healthy controls. Patients with higher levels of IL-17 have a more severe asthma phenotype. Biologics are available for T helper 2 (Th2)-high asthmatics, but the Th17-high subpopulation has a relatively low response to these treatments, rendering it a rather severe asthma phenotype to treat. Several experimental models suggest that targeting the IL-17 pathway may be beneficial in asthma. Moreover, as increased activation of the Th17/IL-17 axis is correlated with reduced inhaled corticosteroids (ICS) sensitivity, targeting the IL-17 pathway might reverse ICS unresponsiveness. In this review, we present and discuss the current knowledge on the role of IL-17 in asthma and its interaction with the Th2 pathway, focusing on the rationale for therapeutic targeting of the IL-17 pathway.

Effect of Vernonia amygdalina Del. Leaf Ethanolic Extract on Intoxicated Male Wistar Rats Liver.

Vernonia amygdalina has been shown to have antioxidant activity, and is also expected to have hepatoprotective activity. This study was conducted to study the effect of V. amygdalina ethanol extracts on intoxicated rat livers. Fresh leaves were extracted in ethanol, and the hepatoprotective activity was tested on male Wistar rats induced with a combination of isoniazid (INH) and rifampicin. Parameters observed were the activity of the enzyme alanine transferase (ALT), serum albumin levels, liver index, and histopathological of the rat liver. The results showed that 50 and 100 mg/kg rat body weight of V. amygdalina ethanol extracts could prevent liver intoxication, starting on day 14. Based on serum albumin concentrations and ALT activity, the high dose extract (100 mg/kg) was more potent as a hepatoprotective agent compared to the extract at a low dose (50 mg/kg). The group of rats treated with a high dose extract showed normal liver index compared to the positive control. Through histology examination, the liver of rats treated with a high dose extract (100 mg/kg) showed minimal liver cell structure damage, and showed similar patterns to the normal rat. Based on these results, it can be concluded that V. amygdalina ethanol extracts can be used to protect the liver in a combination of INH and rifampicin as antituberculosis treatment.