The cumulus oophorus, (discus proligerus), is a cluster of cells that surround the oocyte both in the ovarian follicle and after ovulation. In the

antral follicle An antral follicle, also known as Graafian follicle and tertiary follicle, is an ovarian follicle during a certain latter stage of folliculogenesis. Definitions differ in where the shift into an antral follicle occurs in the staging of follicul ...

, it may be regarded as an extension of the

membrana granulosa The larger ovarian follicles An ovarian follicle is a roughly spheroid cellular aggregation set found in the ovaries. It secretes hormones that influence stages of the menstrual cycle. At the time of puberty, women have approximately 200,000 to ...

. The innermost layer of these cells is the corona radiata. This layer of cells must be penetrated by spermatozoa for fertilization to occur.

Functions

Functions of the cumulus oophorus include coordination of follicular development and oocyte maturation. Mechanisms of the latter include stimulation of amino acid transport and

sterol Sterol is an organic compound with formula , whose molecule is derived from that of gonane by replacement of a hydrogen atom in position 3 by a hydroxyl group. It is therefore an alcohol of gonane. More generally, any compounds that contain the go ...

biosynthesis Biosynthesis is a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms. In biosynthesis, simple compounds are modified, converted into other compounds, or joined to form macromolecules. ...

and regulation of oocyte gene transcription. It also provides energy substrates for oocyte meiotic resumption and promotes glycolysis. Cumulus oophorus cells contribute heavily to the maturation and eventual fertilization of an oocyte. As a follicle grows in size and the antrum develops, more layers of cumulus oophorus cells accumulate around the oocyte to aid in the acrosome reaction and sperm penetration into the oocyte. The proximity between the cumulus oophorus cells and the oocyte favors bidirectional communication, which is vital for oocyte development.

Gene expression profiling

As a part of the process of in vitro fertilization, gene expression profiling of cumulus cells can be performed to estimate oocyte quality and the efficiency of an ovarian hyperstimulation protocol, and may indirectly predict oocyte aneuploidy, embryo development and pregnancy outcomes. Increased knowledge in these aspects is useful in, for example,

embryo selection In vitro fertilisation (IVF) is a process of fertilisation where an egg is combined with sperm in vitro ("in glass"). The process involves monitoring and stimulating an individual's ovulatory process, removing an ovum or ova (egg or eggs) f ...

. In gene expression profiling of cumulus cells, genes where increased expression is correlated with higher oocyte competence or better pregnancy outcomes, include:

HAS2 Hyaluronan synthase 2 is an enzyme that in humans is encoded by the ''HAS2'' gene. Hyaluronan or hyaluronic acid is a high molecular weight unbranched polysaccharide synthesized by a wide variety of organisms from bacteria to mammals, and is a co ...

GREM1 Gremlin is an inhibitor in the TGF beta signaling pathway. It primarily inhibits bone morphogenesis and is implicated in disorders of increased bone formation and several cancers. Structure Gremlin1, previously known as Drm, is a highly con ...

and PTGS2. In contrast, genes where increased expression is correlated with lower oocyte competence or worse pregnancy outcomes include: BDNF,

CCND2 G1/S-specific cyclin-D2 is a protein that in humans is encoded by the ''CCND2'' gene. Function The protein encoded by this gene belongs to the highly conserved cyclin family, whose members are characterized by a dramatic periodicity in protein ...

, CXCR4,

GPX3 Glutathione peroxidase 3 (GPx-3), also known as plasma glutathione peroxidase (GPx-P) or extracellular glutathione peroxidase is an enzyme that in humans is encoded by the ''GPX3'' gene. GPx-3 belongs to the glutathione peroxidase family, which f ...

, HSPB1, DVL3,

DHCR7 7-Dehydrocholesterol reductase, also known as DHCR7, is a protein that in humans is encoded by the ''DHCR7'' gene. Function The protein encoded by this gene is an enzyme catalyzing the production of cholesterol from 7-Dehydrocholesterol usi ...

, CTNND1, TRIM28,

STAR A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

AREG Amphiregulin, also known as AREG, is a protein synthesized as a transmembrane glycoprotein with 252 aminoacids and it is encoded by the ''AREG'' gene. in humans. Function The protein encoded by this gene is a member of the epidermal growth fac ...

, CX43, PTGS2,

SCD1 Stearoyl-CoA desaturase (Δ-9-desaturase) is an endoplasmic reticulum enzyme that catalyzes the rate-limiting step in the formation of monounsaturated fatty acids (MUFAs), specifically oleate and palmitoleate from stearoyl-CoA and palmitoyl-CoA ...

and SCD5.

References

External links

* - "Mammal, bovine ovary (LM, Medium)" * * * - "Female Reproductive System: ovary, cumulus oophorus" {{DEFAULTSORT:Cumulus Oophorus Mammal female reproductive system