Indian Scientists Discover Genetic Switch Controlling Embryo Implantation

During a study by the Indian Council of Medical Research (ICMR) to understand the onset of pregnancy, researchers discovered a “genetic switch” that helps embryos attach to the uterine lining, enabling pregnancy.

For pregnancy to begin, the embryo must first connect to and embed in the uterine lining, but how this occurs was previously unclear.

Published in the international journal Cell Death Discovery, the study reveals a fundamental biological switch that regulates embryo implantation. The research was conducted collaboratively by ICMR-NIRRCH, Mumbai, Banaras Hindu University (BHU), Varanasi, and the Indian Institute of Science (IISc), Bengaluru, involving experts in molecular biology, genomics, and mathematical modeling.

According to Dr. Deepak Modi, ICMR-NIRRCH scientist and lead author, two genes—HOXA10 and TWIST2—temporarily open or close a small site on the uterine lining at the right time. He explained that the uterine lining acts like a fortress wall, generally closed to prevent entry.

Lead researcher Nancy Ashri added that successful implantation requires a small "door" to open at the embryo’s entry point. HOXA10 keeps the lining closed and secure, but temporarily switches off when the embryo arrives, allowing TWIST2 to soften and relax uterine cells, creating a passage for the embryo to embed.

The study found this HOXA10-TWIST2 switch occurs across species, including mice, monkeys, and human cells. Dr. Geetanjali Sachdeva, Director of ICMR-NIRRCH, noted that understanding this process could explain why some women fail to achieve pregnancy despite healthy embryos.

If the uterine lining opens too little, embryos cannot implant; if it opens too much, pregnancy cannot be maintained. Controlling the balance between HOXA10 and TWIST2 could potentially improve IVF success rates in the future.