Comprehensive peripheral blood immunoprofiling reveals five immunotypes with immunotherapy response characteristics in patients with cancer.

The lack of comprehensive diagnostics and consensus analytical models for evaluating the status of a patient's immune system has hindered a wider adoption of immunoprofiling for treatment monitoring and response prediction in cancer patients. To address this unmet need, we developed an immunoprofiling platform that uses multiparameter flow cytometry to characterize immune cell heterogeneity in the peripheral blood of healthy donors and patients with advanced cancers. Using unsupervised clustering, we identified five immunotypes with unique distributions of different cell types and gene expression profiles. An independent analysis of 17,800 open-source transcriptomes with the same approach corroborated these findings. Continuous immunotype-based signature scores were developed to correlate systemic immunity with patient responses to different cancer treatments, including immunotherapy, prognostically and predictively. Our approach and findings illustrate the potential utility of a simple blood test as a flexible tool for stratifying cancer patients into therapy response groups based on systemic immunoprofiling.

Tau differentially regulates the transport of early endosomes and lysosomes.

Microtubule-associated proteins (MAPs) modulate the motility of kinesin and dynein along microtubules to control the transport of vesicles and organelles. The neuronal MAP tau inhibits kinesin-dependent transport. Phosphorylation of tau at Tyr-18 by fyn kinase results in weakened inhibition of kinesin-1. We examined the motility of early endosomes and lysosomes in cells expressing wild-type (WT) tau and phosphomimetic Y18E tau. We quantified the effects on motility as a function of the tau expression level. Lysosome motility is strongly inhibited by tau. Y18E tau preferentially inhibits lysosomes in the cell periphery, while centrally located lysosomes are less affected. Early endosomes are more sensitive to tau than lysosomes and are inhibited by both WT and Y18E tau. Our results show that different cargoes have disparate responses to tau, likely governed by the types of kinesin motors driving their transport. In support of this model, kinesin-1 and -3 are strongly inhibited by tau while kinesin-2 and dynein are less affected. In contrast to kinesin-1, we find that kinesin-3 is strongly inhibited by phosphorylated tau.

Acetylated Microtubules Are Preferentially Bundled Leading to Enhanced Kinesin-1 Motility.

The motor proteins kinesin and dynein transport organelles, mRNA, proteins, and signaling molecules along the microtubule cytoskeleton. In addition to serving as tracks for transport, the microtubule cytoskeleton directs intracellular trafficking by regulating the activity of motor proteins through the organization of the filament network, microtubule-associated proteins, and tubulin posttranslational modifications. However, it is not well understood how these factors influence motor motility, and in vitro assays and live cell observations often produce disparate results. To systematically examine the factors that contribute to cytoskeleton-based regulation of motor protein motility, we extracted intact microtubule networks from cells and tracked the motility of single fluorescently labeled motor proteins on these cytoskeletons. We find that tubulin acetylation alone does not directly affect kinesin-1 motility. However, acetylated microtubules are predominantly bundled, and bundling enhances kinesin run lengths and provides a greater number of available kinesin binding sites. The neuronal MAP tau is also not sensitive to tubulin acetylation, but enriches preferentially on highly curved regions of microtubules where it strongly inhibits kinesin motility. Taken together, these results suggest that the organization of the microtubule network is a key contributor to the regulation of motor-based transport.