Effect of spontaneous term labour on the expression of the NR4A receptors nuclear receptor related 1 protein (Nurr1), neuron-derived clone 77 (Nur77) and neuron-derived orphan receptor 1 (NOR1) in human fetal membranes and myometrium

The function of nuclear hormone receptor 4A signaling in the human reproductive system: A review

AIM

This review aims to summarize the research focused upon the functions of nuclear hormone receptor 4A (NR4A) in the human reproductive system. The research questions addressed are to decipher what role the NR4A subfamily plays in the regulation of the human reproductive system and effects upon fertility issues through regulation of the expression of the NR4A subfamily.

METHODS

The electronic database PubMed was searched for studies published before November 2021. Keywords included "NR4A," "trophoblast," "decidualization," "folliculogenesis," "estrogen," "pregnancy," "Leydig cells," "fertility," and "reproductive." Relevant references from retrieved manuscripts and review articles were also searched manually.

RESULTS

NR4A subfamily are involved in trophoblast differentiation, endometrial decidualization, embryo adhesion, secretion of related hormones, and regulation of spontaneous term labor. Besides, many studies have provided strong evidence that they play critical roles in spermatogenesis. Furthermore, Multiple mechanisms can affect the expression of NR4As. Broadly, NR4A family receptors affect the human reproductive system in multiple ways.

CONCLUSIONS

Further research is needed to specifically dissect the functions and regulatory mechanisms of these receptors and their pharmaceutical antagonists and agonists. The connection between the NR4A subfamily and a variety of reproductive disorders needs to be proven experimentally such that further examination of human tissue is required to assess the role of these receptors in human reproductive diseases.

Pathophysiological Implication of Pattern Recognition Receptors in Fetal Membranes Rupture: RAGE and NLRP Inflammasome

Preterm prelabor ruptures of fetal membranes (pPROM) are a pregnancy complication responsible for 30% of all preterm births. This pathology currently appears more as a consequence of early and uncontrolled process runaway activation, which is usually implicated in the physiologic rupture at term: inflammation. This phenomenon can be septic but also sterile. In this latter case, the inflammation depends on some specific molecules called “alarmins” or “damage-associated molecular patterns” (DAMPs) that are recognized by pattern recognition receptors (PRRs), leading to a microbial-free inflammatory response. Recent data clarify how this activation works and which receptor translates this inflammatory signaling into fetal membranes (FM) to manage a successful rupture after 37 weeks of gestation. In this context, this review focused on two PRRs: the receptor for advanced glycation end-products (RAGE) and the NLRP7 inflammasome.

NURR1 Alterations in Perinatal Stress: A First Step towards Late-Onset Diseases? A Narrative Review

Perinatal life represents a delicate phase of development where stimuli of all sorts, coming to or from the mother, can influence the programming of the future baby's health. These stimuli may have consequences that persist throughout adulthood. Nuclear receptor related 1 protein (NURR1), a transcription factor with a critical role in the development of the dopaminergic neurons in the midbrain, mediates the response to stressful environmental stimuli in the perinatal period. During pregnancy, low-grade inflammation triggered by maternal obesity, hyperinsulinemia or vaginal infections alters NURR1 expression in human gestational tissues. A similar scenario is triggered by exposure to neurotoxic compounds, which are associated with NURR1 epigenetic deregulation in the offspring, with potential intergenerational effects. Since these alterations have been associated with an increased risk of developing late-onset diseases in children, NURR1, alone, or in combination with other molecular markers, has been proposed as a new prognostic tool and a potential therapeutic target for several pathological conditions. This narrative review describes perinatal stress associated with NURR1 gene deregulation, which is proposed here as a mediator of late-onset consequences of early life events.