Drug-regulated CD33-targeted CAR T cells control AML using clinically optimized rapamycin dosing.

Chimeric antigen receptor (CAR) designs that incorporate pharmacologic control are desirable; however, designs suitable for clinical translation are needed. We designed a fully human, rapamycin-regulated drug product for targeting CD33+ tumors called dimerizaing agent-regulated immunoreceptor complex (DARIC33). T cell products demonstrated target-specific and rapamycin-dependent cytokine release, transcriptional responses, cytotoxicity, and in vivo antileukemic activity in the presence of as little as 1 nM rapamycin.

INBRX-120, a CD8α-targeted detuned IL-2 that selectively expands and activates tumoricidal effector cells for safe and durable in vivo responses.

Background: As a major driver of lymphocyte proliferation and activation interleukin 2 (IL-2) is a crucial mediator for antitumor responses. Despite promising activity in a subset of patients, wider therapeutic utility of IL-2 (aldesleukin) has been hampered by severe dose-limiting toxicities, the expansion of immunosuppressive regulatory T cells and a poor pharmacokinetic (PK) profile. Recent engineering efforts, including non-α IL-2 variants, have lowered the toxicity profile, but have yet to induce meaningful antitumor activity in a wider patient population.

Modulation of CD47-SIRPα innate immune checkpoint axis with Fc-function detuned anti-CD47 therapeutic antibody.

Cluster of differentiation 47 (CD47) is a transmembrane protein ubiquitously expressed on human cells but overexpressed on many different tumor cells. The interaction of CD47 with signal-regulatory protein alpha (SIRPα) triggers a "don't eat me" signal to the macrophage, inhibiting phagocytosis. Thus, overexpression of CD47 enables tumor cells to escape from immune surveillance via the blockade of phagocytic mechanisms.

Streptolysin O Rapidly Impairs Neutrophil Oxidative Burst and Antibacterial Responses to Group A Streptococcus.

Group A Streptococcus (GAS) causes a wide range of human infections, ranging from simple pharyngitis to life-threatening necrotizing fasciitis and toxic shock syndrome. A globally disseminated clone of M1T1 GAS has been associated with an increase in severe, invasive GAS infections in recent decades. The secreted GAS pore-forming toxin streptolysin O (SLO), which induces eukaryotic cell lysis in a cholesterol-dependent manner, is highly upregulated in the GAS M1T1 clone during bloodstream dissemination.

N-terminomics: a high-content screen for protease substrates and their cleavage sites.

Proteases play vital roles in many cellular processes and signaling cascades through specific limited cleavage of their targets. It is important to identify what proteins are substrates of proteases and where their cleavage sites are so as to reveal the molecular mechanisms and specificity of signaling. We have developed a method to achieve this goal using a strategy that chemically tags the substrate's alpha amine generated by proteolysis, enriches for tagged peptides, and identifies them using liquid chromatography-coupled tandem mass spectrometry (LC-MS/MS).

Structural and kinetic determinants of protease substrates.

Two fundamental questions with regard to proteolytic networks and pathways concern the structural repertoire and kinetic threshold that distinguish legitimate signaling substrates. We used N-terminal proteomics to address these issues by identifying cleavage sites within the Escherichia coli proteome that are driven by the apoptotic signaling protease caspase-3 and the bacterial protease glutamyl endopeptidase (GluC). Defying the dogma that proteases cleave primarily in natively unstructured loops, we found that both caspase-3 and GluC cleave in alpha-helices nearly as frequently as in extended loops.

Notochord-derived BMP antagonists inhibit endothelial cell generation and network formation.

Embryonic blood vessel formation is initially mediated through the sequential differentiation, migration, and assembly of endothelial cells (ECs). While many molecular signals that promote vascular development have been identified, little is known about suppressors of this process. In higher vertebrates, including birds and mammals, the vascular network forms throughout the embryonic disk with the exception of a region along the midline.

Streptolysin O promotes group A Streptococcus immune evasion by accelerated macrophage apoptosis.

Group A Streptococcus (GAS) is a leading human bacterial pathogen capable of producing invasive infections even in previously healthy individuals. As frontline components of host innate defense, macrophages play a key role in control and clearance of GAS infections. We find GAS induces rapid, dose-dependent apoptosis of primary and cultured macrophages and neutrophils.

Profiling constitutive proteolytic events in vivo.

Most known organisms encode proteases that are crucial for constitutive proteolytic events. In the present paper, we describe a method to define these events in proteomes from Escherichia coli to humans. The method takes advantage of specific N-terminal biotinylation of protein samples, followed by affinity enrichment and conventional LC (liquid chromatography)-MS/MS (tandem mass spectrometry) analysis.

Identification of proteolytic cleavage sites by quantitative proteomics.

The identification of natural substrates and their cleavage sites is pivotal to defining proteolytic pathways. Here we report a novel strategy for the identification of the signature of proteolytic cleavage events based on quantitative proteomics. Lysine residues in proteins are blocked by guanidination so that free N-terminals can be labeled with amine-specific iTRAQ reagents.

The apoptosome activates caspase-9 by dimerization.

The apical protease of the human intrinsic apoptotic pathway, caspase-9, is activated in a polymeric activation platform known as the apoptosome. The mechanism has been debated, and two contrasting hypotheses have been suggested. One of these postulates an allosteric activation of monomeric caspase-9; the other postulates a dimer-driven assembly at the surface of the apoptosome--the "induced proximity" model.

Tissue morphogenesis and vascular stability require the Frem2 protein, product of the mouse myelencephalic blebs gene.

Adhesive properties of cells undergoing morphogenetic rearrangements can be regulated either at the cellular level or by altering the environment in which rearrangements occur. Here, we describe the identification of a mutation (my(F11)) in the mouse extracellular matrix component Frem2, and provide evidence that suggests Frem2 expression creates an environment conducive to morphogenetic events. Loss of Frem2 function results in defects in developmental events associated with morphogenetic rearrangements of the vasculature and of tissues arising from all germ layers.

The activin signaling pathway promotes differentiation of dI3 interneurons in the spinal neural tube.

The generation of the appropriate types and numbers of mature neurons during the development of the spinal cord requires the careful coordination of patterning, proliferation, and differentiation. In the dorsal neural tube, this coordination is achieved by the combined action of multiple ligands of both the Wnt and TGF-beta families, and their effectors, such as the bHLH proteins. TGF-beta signaling acting through the BMP receptors is necessary for the generation of several dorsal interneuron types.

Analysis of mouse embryonic patterning and morphogenesis by forward genetics.

Many aspects of the genetic control of mammalian embryogenesis cannot be extrapolated from other animals. Taking a forward genetic approach, we have induced recessive mutations by treatment of mice with ethylnitrosourea and have identified 43 mutations that affect early morphogenesis and patterning, including 38 genes that have not been studied previously. The molecular lesions responsible for 14 mutations were identified, including mutations in nine genes that had not been characterized previously.

Recruitment of the proneural gene scute to the Drosophila sex-determination pathway.

In flies, scute (sc) works with its paralogs in the achaete-scute-complex (ASC) to direct neuronal development. However, in the family Drosophilidae, sc also acquired a role in the primary event of sex determination, X chromosome counting, by becoming an X chromosome signal element (XSE)-an evolutionary step shown here to have occurred after sc diverged from its closest paralog, achaete (ac). Two temperature-sensitive alleles, sc(sisB2) and sc(sisB3), which disrupt only sex determination, were recovered in a powerful F1 genetic selection and used to investigate how sc was recruited to the sex-determination pathway.

Zic1 represses Math1 expression via interactions with the Math1 enhancer and modulation of Math1 autoregulation.

Math1 is a basic helix-loop-helix transcription factor expressed in progenitor cells that give rise to dorsal commissural interneurons in the spinal cord, granule cells of the cerebellum, and sensory cells in the inner ear and skin. Transcriptional regulation of this gene is tightly controlled both temporally and spatially during nervous system development. The signals that mediate this regulation are likely integrated at the Math1 enhancer, which is highly conserved among vertebrate species.

BMP signaling patterns the dorsal and intermediate neural tube via regulation of homeobox and helix-loop-helix transcription factors.

In the spinal neural tube, populations of neuronal precursors that express a unique combination of transcription factors give rise to specific classes of neurons at precise locations along the dorsoventral axis. Understanding the patterning mechanisms that generate restricted gene expression along the dorsoventral axis is therefore crucial to understanding the creation of diverse neural cell types. Bone morphogenetic proteins (BMPs) and other transforming growth factor beta (TGFbeta) proteins are expressed by the dorsal-most cells of the neural tube (the roofplate) and surrounding tissues, and evidence indicates that they play a role in assigning cell identity.