Impairments in macroautophagy/autophagy, which degrades dysfunctional organelles as well as long-lived and aggregate proteins, are associated with several cardiomyopathies; however, the regulation of cardiac autophagy remains insufficiently understood. In this regard, ULK1 and ULK2 are thought to play primarily redundant roles in autophagy initiation, but whether their function is developmentally determined, potentially having an impact on cardiac integrity and function remains unknown. Here, we demonstrate that perinatal loss of ULK1 or ULK2 in cardiomyocytes (cU1-KO and cU2-KO mice, respectively) enhances basal autophagy without altering autophagy machinery content while preserving cardiac function. This increased basal autophagy is dependent on the remaining ULK protein given that perinatal loss of both ULK1 and ULK2 in cU1/2-DKO mice impaired autophagy causing age-related cardiomyopathy and reduced survival. Conversely, adult loss of cardiac ULK1, but not of ULK2 (i.e., icU1-KO and icU2-KO mice, respectively), led to a rapidly developing cardiomyopathy, heart failure and early death. icU1-KO mice had impaired autophagy with robust deficits in mitochondrial respiration and ATP synthesis. Trehalose ameliorated autophagy impairments in icU1-KO hearts but did not delay cardiac dysfunction suggesting that ULK1 plays other critical, autophagy-independent, functions in the adult heart. Collectively, these results indicate that cardiac ULK1 and ULK2 are functionally redundant in the developing heart, while ULK1 assumes a more unique, prominent role in the adult heart. Abbreviations: ATG4: autophagy related 4, cysteine peptidase; ATG5: autophagy related 5; ATG7: autophagy related 7; ATG9: autophagy related 9; ATG13: autophagy related 13; CYCS: Cytochrome C; DNM1L, dynamin 1-like; MAP1LC3A: microtubule-associated protein 1 light chain 3 alpha; MAP1LC3B: microtubule-associated protein 1 light chain 3 beta; MFN1: mitofusin 1; MFN2: mitofusin 2; MT-CO1: mitochondrially encoded cytochrome c oxidase I; MYH: myosin, heavy polypeptide; NBR1: NBR1 autophagy cargo receptor; NDUFA9: NADH:ubiquinone oxidoreductase subunit A9; OPA1: OPA1, mitochondrial dynamin like GTPase; PPARGC1A, peroxisome proliferator activated receptor, gamma, coactivator 1 alpha; SDHA: succinate dehydrogenase complex, subunit A, flavoprotein (Fp); SQSTM1: sequestosome 1; ULK1: unc-51 like kinase 1; ULK2: unc-51 like kinase 2; UQCRC1: ubiquinol-cytochrome c reductase core protein 1

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Autophagy is a conserved cellular process that degrades dysfunctional organelles and long‐lived proteins. Insufficient autophagy contributes to several cardiomyopathies; however, the regulation of cardiac autophagy is still evolving. To this matter, Unc‐51 like autophagy activating kinases 1 and 2 (ULK1 and ULK2) are thought to play a primarily redundant role in autophagy initiation but their function in the heart remains insufficiently understood. Here, we first studied mice with embryonic cardiac‐specific deletion of Ulk1 or Ulk2 (cU1‐KO and cU2‐KO). Unexpectedly, adult cU1‐KO and cU2‐KO mice presented enhanced basal cardiac autophagy despite unchanged expression of essential autophagy machinery proteins. Cardiac function was unaltered in these mice. We then tested if this autophagy overcompensation relied on the remaining ULK protein by studying mice with embryonic cardiac‐specific deletion of both Ulk1 and Ulk2 (cU1/2‐DKO). Indeed, autophagy was impaired in cU1/2‐DKO leading to an aging‐associated cardiomyopathy and reduced survival. Next, we tested if the overall autophagy overcompensation resulting from the loss of a single cardiac Ulk was only feasible at early stages of development by studying mice with adult deletion of either Ulk1 or Ulk2 (i.e., icU1‐KO and icU2‐KO). Interestingly, while adult loss of ULK2 had no discernable effect on cardiac autophagy or function, loss of ULK1 caused a rapidly developing cardiomyopathy, heart failure and early death. Mechanistically, adult loss of cardiac ULK1 impaired autophagy and led to an overall fissed mitochondrial reticulum with deficiencies in respiration and ATP re‐synthesis. Altogether our results demonstrate that the impact of ULK1 and ULK2 loss on cardiac autophagy and function is developmentally determined. Further, although ULK1 and ULK2 appear to have redundant roles in modulating cardiac autophagy during development, only ULK1 is essential for maintenance of basal cardiac homeostasis in adulthood.

In this paper, a novel micro pseudo-spherical lens is proposed to resolve the intrinsic high insertion loss problem associated with the micro spherical lens, and yet retain its other good qualities. The design parameters for this micro pseudo-spherical lens are optimized using Gaussian beam matrix propagation method. A geometric ray-tracing program is also used to calculate the coupling efficiency for collimator pairs. The simulation results for all four different types of micro lenses (pseudo-spherical, spherical, aspheric and GRIN lenses) are presented and compared to experimental results. It is shown that the novel micro pseudo-spherical lens presents significant performance improvement over the micro spherical lens, and offer similar performance to GRIN and micro aspheric lenses.