INTRODUCTION:

Polycystic ovary syndrome is criticalendocrinopathy affects 6-21% of women of child-wearing agecategorized by hyperandrogenism and anovulation¹. Hyperinsulinemia and insulin resistance are mutually crucial hallmarks of PCOS,contributes to a clusterofrisk factors for cardiometabolic disorders and various cancers of reproductive system in women². Excessive steroidogenesis,variations in genetic events and environmental factorsorchestrate metabolic and reproductive dysfunction in women. Traditionally, transvaginal pelvic ultrasound and total-testosterone measurements has been assessed to diagnose PCOS. Since 50–60% of PCOS patients have high risk ofsystemic and metabolic syndrome, dyslipidemia, insulin resistance (IR) and cardiovascular diseases patients³.

Therefore, the analysis of multiple factors is highly needed to achieve a more reliable diagnosis of PCOS.

To improve early diagnosis several enzyme, protein and genetic variations can be attributed as a biochemical diagnostic marker of PCOS. Thisreview aims to briefly discuss these new markers to get better the diagnosis and handling of PCOS as well reduce the risk of long-term complications.

Novel genes in PCOS:

The multiple transcription factors and genetic circuits are highly arranged for the ovarian development. Any disturbance or modulation of this organized genetic network can lead to many reproductive or cosmetic dysfunction, PCOS and ovarian cancer⁴.

CYP genes:

Cytochrome side-chain cleavage enzyme catalyzes the initial steps of biosynthesis of the steroidal hormones. Polymorphisms in CYP genes may result in upregulation or downregulation of their expression to aggravate the hyperandrogenism in women to cause PCOS⁵. Genes like CYP11A (cytochrome P450 side-chain cleavage enzyme gene), CYP17(cytochrome P450 17hydroxylase/17, 20-desmolase gene) and CYP19 (aromatase)encode for the different enzymes that involved in PCOS pathophysiology. Overproduction of 17-OH progesteroneand testosterone in granulosa cells and declined activity of aromatase causes hyperandrogenism in ovarian theca cells⁶. Apreclinical study on rabbits had also been shown absence of steroid synthesis with the deletion of CYP11 gene. Hence forth, it suggested that the action of this enzyme CYP11 gene initiates the steroidogenesis. Several polymorphic studies on the CYP11 gene with altered gene expression have been carried out in PCOS. The polymorphism-induced over-expression in CYP11A gene also results in high production of androgen. CYP17 gene is located on 10q24 and q25 chromosome that encodes for the enzyme cytochrome P450 17α-hydroxylase-17-20-lyase whereas CYP19 gene is responsible for aromatase activity⁷. Clinically, many studies in Greek and Korean patients showed a significant high gene expression of the CYP17 in women suffering from PCOS⁸. CYP19 gene is located at 15p21 domain and encodes for the enzyme P450 aromatase. PCOS follicles have decreased contained and hence low levels of estradiol⁹. This fall in aromatase action is contributing to abnormal follicular development. Su et al. demonstrated that PCOS follicles exhibit low levels of P450arom mRNA¹⁰. This study showed decreased aromatase activity which is generally responsible for androgen excess in PCOS.

Sirtuins:

Sirtuins (SIRT1–SIRT7) belongs to deacetylases that can modify structural protein stopossess a conservative catalytic domain in various processes like to maintain metabolic homeostasis, oxidative behaviour, aging, degeneration of the regulating gene expressions and modulation of other proteins to change cellular localization and their functions¹¹. Evidences suggest that express all seven members of the sirtuin family of genes are found in human ovarian follicles¹². Overexpression of sirtuins in luteinizing granulosa cells in IVF patients was compared with infertility diagnostic groups and in oocyte donor group by quantified qRT-PCR¹³. The study significantly found the involvement of SIRT1 in progression of inﬂammation (NF-κB involvement), energy metabolism (PPAR-γ involvement) and apoptosis (inhibition of p53-dependent transcription)¹⁴.

AR Gene (Androgen Receptor Gene)

Chromosome-Xq12 has 11-exons contains androgen receptor gene which is X linked gene. It has three functional domains those codes for more than 90 kb long protein. However, X inactivation in Chromosome-Xq12 gene disturbs androgen signalling pathway¹⁵. The novel mutations of AR may be of great interest to understand genomic pathological expansion of PCOS¹⁶.

CBX2 (Chromobox homolog 2):

Recently, dual isoforms of CBX2 genome (CBX2.1 and CBX2.2) have been confirmed in both male and female reproductive systems. CBX2.2 lacks the polycomb box. This polycomb box controls MAP3K15 (mitogen-activated-protein-3-kinase 15) and AKR1C1 (Aldo-keto reductase family 1 member C1) expression by reverse feedback mechanism¹⁷. Inactivation of MAPK causes excessive testosterone production in PCOS women. In rat ovaries,the altered expression patterns of MAPKs were significantly much greater during the secondary and antral follicle stages when compared tothose in the primordial follicles, primary follicles, and corpora lutea¹⁸. Adrenal tissues are abundant of ldo-keto reductase steroidogenic enzymes considerably during polycystic ovary syndrome^19,20. In pathology of PCOS, these androgen recursors are crucial for androgen and estrogen synthesis. Whilst there is emerging evidence that regulation of androgen receptor in the ovary can be precededvia the control of AKR1C1 expression via CBX2.2²¹, so far advanced study is still demanding exploration of role of CBX2 network involved in ovarian functionality in humans and to show how these new targets can be beneficial in development of new treatment modalities.

MicroRNAs (miRNAs):

Epigenetic changes in methylation and miRNAs exposed further fascinating concept of regulations affecting the phenotype of PCOS women²². Dysregulation of circulating or ovarian miRNAs can affect steroidogenesis and normal ovarian functions in PCOS women²³. Recent studies examined the down regulation of miR-324 expression in the PCOS ovaries and granulosa cell-lines²⁴.

DENND1A:

DENND1A is another more interesting locus which is recognized through various advanced genetic studies. Upregulation of DENND1Agenein theca cells and adrenal cell-lines leads to upsurge inenzyme expression of CYP17A1 and CYP11A1. However, the mechanistical pathways involved into over-expression of DENND1A remain to be revealed²⁵.

KISS1 Gene:

KISS1 gene encodes for kisspeptins, produced by Kisspeptin-1neurons.They act as regulators for GnRH neurosecretion and ovulation²⁶. In advanced research studies, mammalian ovary is expressed with kisspeptin-1 and its receptors. These genes involve into initiation of puberty, development of follicles, maturation of oocyte, steroidogenesis, and ovulation²⁷. However, failure of kisspeptin–LH pulse coupling results in oligomenorrhea in PCOS women and down-regulation of KISS1 functioning leads to female infertility^28,29. Other many neurotransmitters include neurokinin B (NKB) and dynorphin are also found in Kiss1 neurons and show foremost roles to regulate the secretion of GnRH/ gonadotropin³⁰. Preclinical models of PCOS have expressed continuous suppression of hypothalamic KISS1 to cause extreme androgen production³¹.

Protein biomarkers in PCOS:

Fetuin-A:

Fetuin-A, is an adipokine secreted by the adipose tissues³². Advanced studies have suggested that polymorphisms of fetuin-A lead to type-2 diabetes mellitus and alteration in serum fetuin-A levels was also observed in obese patients and obesity is one of the hallmarks of metabolic syndrome³³. A prospective case control study revealed that high serum fetuin-A levels in obese-PCOS patients may be a potential marker to show metabolic dysfunction.

Galanin:

Galanin isa neuropeptide, found in the central nervous system (CNS), peripheral nervous system (PNS) and reproductive system in both genders³⁴. It plays various roles in the body via its three members (GAL1, GAL2 and GAL3). These members belong to G-protein-coupled receptor (GPCR) superfamily and various related signalling pathways^35,36.

Hypothalamus has a subset of neurons which produces GnRH. This subset also synthesizes galanin. Furthermore, GnRH neurons are expressed as estrogen-inducible galanin gene expression. GAL2 has been commonly spread in the ovary which helps in generation of preovulatory LH surge along with gonadotropin secretions^37,38. Dysregulated gonadal secretion indicates its significant role in development of PCOS in patients³⁹. Clinically, galan in peptides could significantly reduce TNF-α, IL-6 levels (inﬂammatory markers), raise FSH level and reduce LH, insulin, and testosterone levels, henceforth may be an admirable therapeutic choice for PCOS management.

Ghrelin:

Ghrelin is a peptide-hormone which is secreted in stomach to stimulate many biological functions (such as glucose uptake, food intake and reproductive system). The relationship between ghrelin and IR has been assessed in patients with PCOS. Lower levels of ghrelin were found in insulin-resistant PCOS women⁴⁰. Henceforth, metformin therapy could be better option to improve insulin sensitivity and increase the serum ghrelin levels in insulin resistant PCOS women.

Podocalyxin:

Podocalyxin is a podocyte-associated protein which is mainly expressed in vascular endothelial cells linked with carotid intima thickness, involvedas a novel marker for endothelial cell dysfunction and atherosclerosis. Elevated levels of Podocalyxinare also common during preeclampsia⁴¹. Henceforth, PCOS can be probably considered as a multifaceted syndrome with extensive long-term cardiovascular diseases.

Enzyme biomarkers in PCOS:

Serum paraoxonase-1 (PON-1):

Serum paraoxonase-1 (PON-1) is one of the enzymes mainly expressed in liver cells⁴². PON-1 enzyme is encoded by PON-1 gene which is primarily associated with high-density lipoprotein (HDL). Low levels of serum PON-1 has been observed during impaired metabolic function and results into oxidative insult⁴³. This low PON-1 level may also cause insulin resistance in PCOS. Increased oxidative stress leadsto decreased PON-1 activity in PCOS women⁴⁴

CONCLUSION:

Earlier it was assumed that PCOS affects only cases of fertility but it has now been proven that PCOS is associated with life detrimental consequences such as hyperinsulinism, diabetes mellitus, cardiovascular disease, and other morbidities. Previously PCOS was diagnosed only by serum testosterone and pelvic scans. Due to unfolding of various etiology and molecular pathways responsible for PCOS, recent advances are now serving many potential novel markers of IR, obesity and hyperandrogenism in PCOS. It was found that a strong connection lies between proteins and PCOS, while their role needs to be explored more to assess the insulin resistance, to predict the diagnosis of metabolic, cosmetology and cardiovascular consequences in PCOS, to advance the use of medical resources, and to decrease the costs and side effects of existing options. Further investigation is essential to simplify the role of these proteins mainly accompanying with insulin resistance in PCOS syndrome.

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Received on 21.12.2022 Modified on 04.07.2023

Research J. Pharm. and Tech 2024; 17(1):439-442.

DOI: 10.52711/0974-360X.2024.00069