Modulation of Human Dendritic Cell Functions by Phosphodiesterase-4 Inhibitors: Potential Relevance for the Treatment of Respiratory Diseases

Janus Kinase Inhibitors as a Third-Line Therapy for Refractory Endogenous Noninfectious Uveitis

PURPOSE

Janus kinase (JAK) inhibitors have recently been used to treat patients with biologic refractory noninfectious uveitis (NIU). This narrative review updates the current evidence relevant for their application in patients with refractory NIU.

METHODS

A literature search was performed for articles published until October 2023 in the PubMed, Scopus, and CENTRAL databases using the key terms "noninfectious uveitis" and "Janus kinase inhibitor" or "JAK inhibitor" without any exclusion criteria. Published articles were selected based on their clinical focus, relevance for ocular disease, time since publication and study design reflecting their scientific soundness with a critical appraisal of drug safety aspects.

RESULTS

Janus kinases are transmembrane signaling proteins. Their inhibition has shown therapeutic potential experimentally and in patients with multiple immune-mediated diseases, including NIU. JAK inhibitors differ from biological agents in that they inhibit not one specific but multiple cytokines. These agents can be ingested orally and seem superior to adalimumab for most indications. While there is no doubt regarding their efficacy in treating immune-mediated inflammatory diseases, reports regarding their safety are increasing, and the findings are generally confusing and contradictory. Since substantiated information about their specific safety profiles in patients with inflammatory eye disease is lacking, their position in the therapeutic algorithm for uveitis has yet to be determined.

CONCLUSIONS

In the absence of evidence from controlled clinical trials, JAK inhibitor therapy is still rendered experimental and currently considered only for sight-threatening uveitis. JAK inhibitors may be considered for specific NIU entities for which there is insufficient response or secondary loss of response to conventional or biologic disease-modifying drugs.

The IL-4/13-induced production of M2 chemokines by human lung macrophages is enhanced by adenosine and PGE2

BACKGROUND AND PURPOSE

Lung macrophages (LMs) are critically involved in respiratory diseases. The primary objective of the present study was to determine whether or not an adenosine analog (NECA) and prostaglandin E2 (PGE2) affected the interleukin (IL)-4- and IL-13-induced release of M2a chemokines (CCL13, CCL17, CCL18, and CCL22) by human LMs.

EXPERIMENTAL APPROACH

Primary macrophages isolated from resected human lungs were incubated with NECA, PGE2, roflumilast, or vehicle and stimulated with IL-4 or IL-13 for 24 h. The levels of chemokines and PGE2 in the culture supernatants were measured using ELISAs and enzyme immunoassays.

KEY RESULTS

Exposure to IL-4 (10 ng/mL) and IL-13 (50 ng/mL) was associated with greater M2a chemokine production but not PGE2 production. PGE2 (10 ng/mL) and NECA (10-6 M) induced the production of M2a chemokines to a lesser extent but significantly enhanced the IL-4/IL-13-induced production of these chemokines. At either a clinically relevant concentration (10-9 M) or at a concentration (10-7 M) that fully inhibited phosphodiesterase 4 (PDE4) activity, roflumilast did not increase the production of M2a chemokines and did not modulate their IL-13-induced production, regardless of the presence or absence of PGE2.

CONCLUSIONS

NECA and PGE2 enhanced the IL-4/IL-13-induced production of M2a chemokines. The inhibition of PDE4 by roflumilast did not alter the production of these chemokines. These results contrast totally with the previously reported inhibitory effects of NECA, PGE2, and PDE4 inhibitors on the lipopolysaccharide-induced release of tumor necrosis factor alpha and M1 chemokines in human LMs.