Cells residing in a microenvironment interact with the extracellular matrix (ECM) and neighboring cells. The ECM built from biomacromolecules often includes nanotopography. Through the ECM, interstitial flows facilitate transport of nutrients and play an important role in tissue maintenance and pathobiology. To create a microenvironment that can incorporate both nanotopography and flow for studies of cell-matrix interactions, we fabricated microfluidic channels endowed with nanopatterns suitable for dynamic culture. Using polymer thin film technology, we developed a versatile stitching technique to generate a large area of nanopatterned surface and a simple microtransfer assembly technique to assemble polydimethylsiloxane-based microfluidics. The cellular study showed that both nanotopography and fluid shear stress played a significant role in adhesion, spreading, and migration of human mesenchymal stem cells. The orientation and deformation of cytoskeleton and nuclei were regulated through the interplay of these two cues. The nanostructured microfluidic platform provides a useful tool to promote the fundamental understanding of cell-matrix interactions and may be used to regulate the fate of stem cells.

No abstract

Markers predicting response and resistance to chimeric antigen receptor (CAR) T cells in relapsed/refractory multiple myeloma are currently missing. We subjected cells isolated from peripheral blood and bone marrow before and after the application of CAR T cells directed against B cell maturation antigen to single cell multi-omic analyses to identify markers associated with resistance and early relapse. Differences between responders and non-responders were already identified at time of leukapheresis. Non-responders showed an immunosuppressive microenvironment characterized by increased numbers of monocytes expressing the immune checkpoint molecule CD39 and suppressing CD8+ and NK cell function. The analyses of CAR T cells showed cytotoxic and exhausted phenotypes in hyperexpanded compared to low/intermediate expanded clones. We identified potential immunotherapeutic targets on CAR T cells, like PD1 and KLRB1, to improve their functionality and durability. Our work provides first evidence that an immunosuppressive microenvironment is associated with resistance to CAR T cell therapies.

No abstract