On the evening of 16 March 2023, the English lecture series Sustainable Development and the Future continued at Tongji University's Siping Campus. For this evening's lecture, we are honored to invite Xue Lei, Distinguished Professor and Chief Scientist of the School of Life Sciences and Technology of Tongji University, to deliver a lecture on the topic of From Life to Death.

Figure 1: Professor Xue Lei is explaining JNK theory

Professor Xue Lei gives an example: Professor Cynthia Kenyang of the University of California did an experiment with nematodes. This is an animal that lives for only 30 days and has 14,000 genes in its body. After 30 days, only one nematode was still alive and its lifespan was successfully extended to 50 days. Following this mutant, she discovered that the gene was called the insulin receptor. In the insulin signaling pathway, life span is extended by slowing down the signal. At the same time, Professor Xue Lei discovered through her own research that another signal, JNK, was found in Drosophila. If this signal is decreased, lifespan decreases, from a maximum of 90 days to 70 days. When the signaling pathway is upregulated, the lifespan increases from 90 days to over 110 days.

Figure 2: Professor Lei Xue is explaining programmed cell death

Professor Xue Lei explains that scientists have identified two types of genes that control 'programmed cell death': those that inhibit cell death, and those that initiate or promote cell death. The interaction of these two types of genes controls the process of cell development. The coexistence of these two mechanisms maintains a dynamic balance between the life and death of the body's cells to ensure the health of the body. Once this balance is disturbed, disease can occur. When cell death is inhibited, cells grow in a disorderly fashion and cause tumors to develop and cancer to form, and conversely, excessive cell death results, as in the case of HIV infection, which disrupts the body's immune function and causes AIDS. The process of cell life and death, which is closely regulated by genes, is of great importance to our understanding of the mechanisms of human health and disease, and to furthering our understanding of the pathogenesis of major diseases such as cancer and AIDS and finding treatments.

Figure 3: Professor Xue Lei is explaining human lifespan

Professor Xue Lei concluded by talking about human longevity and ageing. Each human has 46 chromosomes, which are small yellow particles at the end of each chromosome, and as the years go by, the telomeres wear out and the genes on the chromosomes are lost, causing ageing. Fortunately, scientists have found its nemesis - telomerase. By increasing telomerase activity and maintaining telomere length, we can stay young. Of course, a good lifestyle also helps us look younger. Scientific experiments have proven that a mouse can live from 36 months to more than 50 months if its diet is only half of what it would normally be. The theory is that by controlling your diet, instead of living half as long, you age half as slowly, which means you look like you're 40 when you're 80. (Photo/text by Liu Yongxiang)