Rationale for IL-37 as a novel therapeutic agent in inflammation

Potential Role of IL-37 in Atopic Dermatitis

Interleukin 37 (IL-37) is a recently discovered member of the IL-1 cytokine family that appears to have anti-inflammatory and immunosuppressive effects in various diseases. IL-37 acts as a dual-function cytokine, exerting its effect extracellularly by forming a complex with the receptors IL-18 α (IL-18Rα) and IL-1R8 and transmitting anti-inflammatory signals, as well as intracellularly by interacting with Smad3, entering the nucleus, and inhibiting the transcription of pro-inflammatory genes. Consequently, IL-37 is linked to IL-18, which plays a role in the pathogenesis of atopic dermatitis (AD), consistent with our studies. Some isoforms of IL-37 are expressed by keratinocytes, monocytes, and other skin immune cells. IL-37 has been found to modulate the skewed T helper 2 (Th2) inflammation that is fundamental to the pathogenesis of AD. This review provides an up-to-date summary of the function of IL-37 in modulating the immune system and analyses its potential role in the pathogenesis of AD. Moreover, it speculates on IL-37's hypothetical value as a therapeutic target in the treatment of AD.

A novel approach to achieving more efficient production of the mature form of human IL-37 in plants

Interleukin-37 is a newly discovered cytokine that plays a pivotal role in suppressing innate inflammation and acquired immunity. We have recently expressed both the mature(mat-) and pro-forms of human IL-37b in plants and demonstrated that while both forms of the plant-made hIL-37b are functional, pmat-hIL37b exhibited significantly greater activity than ppro-IL-37b. Compared to ppro-hIL-37b, on the other hand, the expression level of pmat-hIL-37b was substantially lower (100.5 µg versus 1.05 µg/g fresh leaf mass or 1% versus 0.01% TSP). Since the difference between ppro-hIL-37b and pmat-hIL-37b is that ppro-hIL-37b contains a signal sequence not cleavable by plant cells, we reasoned that this signal sequence would play a key role in stabilizing the ppro-hIL-37b protein. Here, we describe a novel approach to enhancing pmat-hIL-37b production in plants based on incorporation of a gene sequence encoding tobacco etch virus (TEV) protease between the signal peptide and the mature hIL-37b, including a TEV cleavage site at the C-termini of TEV protease. The rationale is that when expressed as a sp-TEV-matIL-37b fusion protein, the stabilizing properties of the signal peptide of pro-hIL-37b will be awarded to its fusion partners, resulting in increased yield of target proteins. The fusion protein is then expected to cleave itself in vivo to yield a mature pmat-hIL-37b. Indeed, when a sp-TEV-matIL-37b fusion gene was expressed in stable-transformed plants, a prominent band corresponding to dimeric pmat-hIL-37b was detected, with expression yields reaching 42.5 µg/g fresh leaf mass in the best expression lines. Bioassays demonstrated that plant-made mature pmat-hIL-37b is functional.

The Role of the Interleukin-1 Family in Complications of Prematurity

Preterm birth is a major contributor to neonatal morbidity and mortality. Complications of prematurity such as bronchopulmonary dysplasia (BPD, affecting the lung), pulmonary hypertension associated with BPD (BPD-PH, heart), white matter injury (WMI, brain), retinopathy of prematurity (ROP, eyes), necrotizing enterocolitis (NEC, gut) and sepsis are among the major causes of long-term morbidity in infants born prematurely. Though the origins are multifactorial, inflammation and in particular the imbalance of pro- and anti-inflammatory mediators is now recognized as a key driver of the pathophysiology underlying these illnesses. Here, we review the involvement of the interleukin (IL)-1 family in perinatal inflammation and its clinical implications, with a focus on the potential of these cytokines as therapeutic targets for the development of safe and effective treatments for early life inflammatory diseases.