Single-center randomized trial of T-reg graft alone vs T-reg graft plus tacrolimus for the prevention of acute GVHD.

Allogeneic hematopoietic cell transplantation (HCT) is a curative therapy for hematological malignancies for which graft-versus-host disease (GVHD) remains a major complication. The use of donor T-regulatory cells (Tregs) to prevent GVHD appears promising, including in our previous evaluation of an engineered graft product (T-reg graft) consisting of the timed, sequential infusion of CD34+ hematopoietic stem cells and high-purity Tregs followed by conventional T cells. However, whether immunosuppressive prophylaxis can be removed from this protocol remains unclear.

Neutrophil and monocyte kinetics play critical roles in mouse peritoneal adhesion formation.

Peritoneal adhesions are pathological fibroses that ensnare organs after abdominal surgery. This dense connective tissue can cause small bowel obstruction, female infertility, and chronic abdominal pain. The pathogenesis of adhesions is a fibrotic response to tissue damage coordinated between mesothelial cells, fibroblasts, and immune cells.

Surgical adhesions in mice are derived from mesothelial cells and can be targeted by antibodies against mesothelial markers.

Peritoneal adhesions are fibrous tissues that tether organs to one another or to the peritoneal wall and are a major cause of postsurgical and infectious morbidity. The primary molecular chain of events leading to the initiation of adhesions has been elusive, chiefly due to the lack of an identifiable cell of origin. Using clonal analysis and lineage tracing, we have identified injured surface mesothelium expressing podoplanin (PDPN) and mesothelin (MSLN) as a primary instigator of peritoneal adhesions after surgery in mice.

Mapping the Pairwise Choices Leading from Pluripotency to Human Bone, Heart, and Other Mesoderm Cell Types.

Stem-cell differentiation to desired lineages requires navigating alternating developmental paths that often lead to unwanted cell types. Hence, comprehensive developmental roadmaps are crucial to channel stem-cell differentiation toward desired fates. To this end, here, we map bifurcating lineage choices leading from pluripotency to 12 human mesodermal lineages, including bone, muscle, and heart.

New tools for studying microglia in the mouse and human CNS.

The specific function of microglia, the tissue resident macrophages of the brain and spinal cord, has been difficult to ascertain because of a lack of tools to distinguish microglia from other immune cells, thereby limiting specific immunostaining, purification, and manipulation. Because of their unique developmental origins and predicted functions, the distinction of microglia from other myeloid cells is critically important for understanding brain development and disease; better tools would greatly facilitate studies of microglia function in the developing, adult, and injured CNS. Here, we identify transmembrane protein 119 (Tmem119), a cell-surface protein of unknown function, as a highly expressed microglia-specific marker in both mouse and human.

Upregulation of CD11A on hematopoietic stem cells denotes the loss of long-term reconstitution potential.

Small numbers of hematopoietic stem cells (HSCs) generate large numbers of mature effector cells through the successive amplification of transiently proliferating progenitor cells. HSCs and their downstream progenitors have been extensively characterized based on their cell-surface phenotype and functional activities during transplantation assays. These cells dynamically lose and acquire specific sets of surface markers during differentiation, leading to the identification of markers that allow for more refined separation of HSCs from early hematopoietic progenitors.

Engineered SIRPα variants as immunotherapeutic adjuvants to anticancer antibodies.

CD47 is an antiphagocytic signal that cancer cells employ to inhibit macrophage-mediated destruction. Here, we modified the binding domain of human SIRPα, the receptor for CD47, for use as a CD47 antagonist. We engineered high-affinity SIRPα variants with about a 50,000-fold increased affinity for human CD47 relative to wild-type SIRPα.

Anti-CD47 antibody-mediated phagocytosis of cancer by macrophages primes an effective antitumor T-cell response.

Mobilization of the T-cell response against cancer has the potential to achieve long-lasting cures. However, it is not known how to harness antigen-presenting cells optimally to achieve an effective antitumor T-cell response. In this study, we show that anti-CD47 antibody-mediated phagocytosis of cancer by macrophages can initiate an antitumor T-cell immune response.

Synthesis of a photocaged tamoxifen for light-dependent activation of Cre-ER recombinase-driven gene modification.

We report the design of a water-soluble, quaternized tamoxifen photoprobe and demonstrate its application in light-controlled induction of green fluorescent protein expression via a Cre-ER recombinase system.

A nitric oxide/cysteine interaction mediates the activation of soluble guanylate cyclase.

Nitric oxide (NO) regulates a number of essential physiological processes by activating soluble guanylate cyclase (sGC) to produce the second messenger cGMP. The mechanism of NO sensing was previously thought to result exclusively from NO binding to the sGC heme; however, recent studies indicate that heme-bound NO only partially activates sGC and additional NO is involved in the mechanism of maximal NO activation. Furthermore, thiol oxidation of sGC cysteines results in the loss of enzyme activity.

Nucleotide regulation of soluble guanylate cyclase substrate specificity.

Soluble guanylate cyclase (sGC) serves as a receptor for the signaling agent nitric oxide (NO). sGC synthesis of cGMP is regulated by NO, GTP, ATP, and allosteric activators such as YC-1. The guanylate cyclase activity and adenylate cyclase activity of full-length sGC and the sGC catalytic domain constructs (alpha1(cat)beta1(cat)) are reported here.

Thioredoxin is required for S-nitrosation of procaspase-3 and the inhibition of apoptosis in Jurkat cells.

S-nitrosation is a posttranslational, oxidative addition of NO to cysteine residues of proteins that has been proposed as a cGMP-independent signaling pathway [Hess DT, Matsumoto A, Kim SO, Marshall HE, Stamler JS (2005) Nat Rev Mol Cell Biol 6:150-166]. A paradox of S-nitrosation is that only a small set of reactive cysteines are modified in vivo despite the promiscuous reactivity NO exhibits with thiols, precluding the reaction of free NO as the primary mechanism of S-nitrosation. Here we show that a specific transnitrosation reaction between procaspase-3 and thioredoxin-1 (Trx) occurs in cultured human T cells and prevents apoptosis.