Paternal cardiac injury elicits an inflammatory signal relay to the gonads with intergenerational cardiac effects in vertebrates
The blood-gonadal barrier protects the germline from parental exposures. A phenomenon known as intergenerational inheritance suggests that, exceptionally, this barrier can be surpassed with consequences for the subsequent generation. Specific diet regimes and early traumatic experiences have been among the chronic stressors shown to be able to lead to intergenerational inheritance in mammals. Less is known about how acute stress can affect the germline. Cardiac damage leads to several alterations in peripheral organs and, overall, affects blood flow, metabolism, and the immune response. Whether cardiac damage can also affect the reproductive system is not known and might offer new insights into the potential inheritance of cardiovascular disease. Here, we used zebrafish and mouse models to explore the intergenerational role of cardiac damage and repair. In the first week after a cardiac cryolesion, male zebrafish gonads and gametes activated responses associated with inflammation. In sperm, chromatin accessibility was found altered in response to cardiac cryolesion. Offspring of cryoinjured zebrafish males revealed changes in cardiac function and cardiac gene expression. Induction of systemic sterile inflammation in the paternal generation mimicked cardiac injury effects in the following generation, while anti-inflammatory treatments in the injured paternal generation partially recovered F1 cardiac features. Similar features were found in mouse testis after a neonatal injury, and in the hearts of their offspring, suggesting a conserved role of sterile inflammation as a vector for intergenerational transmission of cardiac injury.