Heterogeneous integration of robust hydrogel and soft MXene shows multifunctional sensing.

Deficiencies in either lamin B1 or lamin B2 cause both defective migration of cortical neurons in the developing brain and reduced neuronal survival. The neuronal migration abnormality is explained by a weakened nuclear lamina that interferes with nucleokinesis, a nuclear translocation process required for neuronal migration. In contrast, the explanation for impaired neuronal survival is poorly understood. We hypothesized that the forces imparted on the nucleus during neuronal migration result in nuclear membrane (NM) ruptures, causing interspersion of nuclear and cytoplasmic contents—and ultimately cell death. To test this hypothesis, we bred Lmnb1-deficient mice that express a nuclear-localized fluorescent Cre reporter. Migrating neurons within the cortical plate of E18.5 Lmnb1-deficient embryos exhibited NM ruptures, evident by the escape of the nuclear-localized reporter into the cytoplasm and NM discontinuities by electron microscopy. The NM ruptures were accompanied by DNA damage and cell death. The NM ruptures were not observed in nonmigrating cells within the ventricular zone. NM ruptures, DNA damage, and cell death were also observed in cultured Lmnb1^−/− and Lmnb2^−/− neurons as they migrated away from neurospheres. To test whether mechanical forces on the cell nucleus are relevant to NM ruptures in migrating neurons, we examined cultured Lmnb1^−/− neurons when exposed to external constrictive forces (migration into a field of tightly spaced silicon pillars). As the cells entered the field of pillars, there were frequent NM ruptures, accompanied by DNA damage and cell death. Significance Deficiencies in lamin B1 or lamin B2 in mice result in markedly reduced neuronal density in the cerebral cortex, but the mechanism has been unclear. We found that deficiencies of either lamin B1 or lamin B2 cause nuclear membrane (NM) ruptures in migrating neurons, accompanied by DNA damage and cell death. Our studies were informative because they uncovered large differences in the frequency of NM repair in lamin B1- and lamin B2-deficient neurons, implying unique functions for the 2 nuclear lamins in maintaining NM integrity. Also, our studies uncovered an important role for mechanical stresses in eliciting NM ruptures, helping to explain the increased frequency of NM ruptures in migrating neurons.

Significance: Commercial strategies to deliver biomolecular cargo ex vivo (e.g., electroporation, lipofection) to clinically relevant cell lines are limited by toxicity, cost, and throughput. These technical limitations have inhibited development of these technologies into streamlined clinical platforms for manufacturing gene-modified stem cells and cancer immunotherapies. Here, we demonstrate an acoustofluidic platform capable of delivering plasmids with high throughput to human T lymphocytes, peripheral blood mononuclear cells, and CD34 ⁺ hematopoietic stem and progenitor cells. Acoustofluidic-treated cells showed evidence of cytosolic DNA delivery, endocytic DNA aggregation, and nuclear membrane rupture. Collectively, these observations demonstrate the utility of this method as a research tool for gene editing applications and mechanistic studies of plasma membrane and nuclear membrane repair.