In June last year, a research paper published in Science made a breakthrough in unveiling the world's first detailed map of senescent cells in fruit fly with single nucleus resolution, which provides an important reference for the research of aging and related diseases.

Before acceptance of the paper, the research team selflessly made the Aging Fly Cell Atlas (AFCA) data portal available to share with global researchers who focus on the fruit fly and aging. Hongjie Li, the corresponding author and assistant professor in Department of Molecular and Human Genetics of Baylor College of Medicine, explained, “Data sharing is critical for rapid development of science. We are willing to share AFCA data for helping people utilized relevant sources to analyze and deeply probe into the secret of aging, so as to find a method to keep health and longevity.”

Surprising findings from continuous “repetition”

Fruit fly is an important experimental model in biological research, which is the subject in two published papers of Hongjie Li.

In 2017, he conducted the first single-cell sequencing research on fruit fly and the research achievement was published on Cell, his first Cell article. Later, he published several papers and became an expert in the field. In March 2022, Hongjie Li published his first paper as first author in Science with other over 40 joint labs studying fruit fly, and in this paper, newly developed single-cell sequencing technology was applied to establish fly cell atlas, laying a basis for following fruit fly aging studies.

To unravel the secret of cell aging, Hongjie Li and his team reared hundreds of strains of fruit fly in lab. For fruit fly used in aging assays, the food was changed every two days. Meanwhile, the number of deaths was recorded, sample collection and single-cell RNA sequencing were performed, gene expression changes in single cells of difference organs were analyzed, and the results were compared with 5-day-old young fly.

Despite considerable operations with tins and bottles in daily work, Hongjie Li thought “new experiments are conducted every day, sometimes same steps are repeated for many days and we probably find nothing most of the time, but occasional surprises can make me excited and feel the infinite charm of science and technology.”  

In line with the constructed fly cell atlas in the first Science paper, the team of Hongjie Li characterized the aging process of 163 distinct cell types in fruit fly in detail, and performed an in-depth analysis of changes in tissue cell composition, the quantity of differentially expressed genes, the changes in the quantity, and cell identities. They ultimately found that direct intervention in follicle cells instead of whole organ can contribute to prolonging the youth of the ovary. In addition, they provided the first finding and validation that adipose cells can increase cell nucleus through nuclear division without cell membrane division. These achievements were finally published on Science in June, 2023.

For the secret of success of science and technology, Hongjie Li concluded, “three letters constitute science and technology: V+W+P. V represents vision, which means to read more, listen to reports and broaden horizons; W represents working hard, which means that no matter how smart you are, you must work hard; P represents passion, which means long-term persistence depends on passion for science and technology.