U.S. tensions with China are fraying long-cultivated academic ties. Will the chill hurt American interests?

In the 1980s, Fu Xiangdong was a young Chinese virology student who came to the United States to study biochemistry. More than three decades later, he had a prestigious professorship in California and was conducting promising research on Parkinson’s disease.

But now Fu is doing his research at a Chinese university. His American career was derailed as U.S.-China relations unraveled, putting his collaborations with a Chinese university under…