A Cre-deleter specific for embryo-derived brain macrophages reveals distinct features of microglia and border macrophages.

Genetic tools to target microglia specifically and efficiently from the early stages of embryonic development are lacking. We generated a constitutive Cre line controlled by the microglia signature gene Crybb1 that produced nearly complete recombination in embryonic brain macrophages (microglia and border-associated macrophages [BAMs]) by the perinatal period, with limited recombination in peripheral myeloid cells. Using this tool in combination with Flt3-Cre lineage tracer, single-cell RNA-sequencing analysis, and confocal imaging, we resolved embryonic-derived versus monocyte-derived BAMs in the mouse cortex. Deletion of the transcription factor SMAD4 in microglia and embryonic-derived BAMs using Crybb1-Cre caused a developmental arrest of microglia, which instead acquired a BAM specification signature. By contrast, the development of genuine BAMs remained unaffected. Our results reveal that SMAD4 drives a transcriptional and epigenetic program that is indispensable for the commitment of brain macrophages to the microglia fate and highlight Crybb1-Cre as a tool for targeting embryonic brain macrophages.

A distinct human cell type expressing MHCII and RORγt with dual characteristics of dendritic cells and type 3 innate lymphoid cells.

Recent studies have characterized various mouse antigen-presenting cells (APCs) expressing the lymphoid-lineage transcription factor RORγt (Retinoid-related orphan receptor gamma t), which exhibit distinct phenotypic features and are implicated in the induction of peripheral regulatory T cells (Tregs) and immune tolerance to microbiota and self-antigens. These APCs encompass Janus cells and Thetis cell subsets, some of which express the AutoImmune REgulator (AIRE). RORγt+ MHCII+ type 3 innate lymphoid cells (ILC3) have also been implicated in the instruction of microbiota-specific Tregs. While RORγt+ APCs have been actively investigated in mice, the identity and function of these cell subsets in humans remain elusive. Herein, we identify a rare subset of RORγt+ cells with dendritic cell (DC) features through integrated single-cell RNA sequencing and single-cell ATAC sequencing. These cells, which we term RORγt+ DC-like cells (R-DC-like), exhibit DC morphology, express the MHC class II machinery, and are distinct from all previously reported DC and ILC3 subsets, but share transcriptional and epigenetic similarities with DC2 and ILC3. We have developed procedures to isolate and expand them in vitro, enabling their functional characterization. R-DC-like cells proliferate in vitro, continue to express RORγt, and differentiate into CD1c+ DC2-like cells. They stimulate the proliferation of allogeneic T cells. The identification of human R-DC-like cells with proliferative potential and plasticity toward CD1c+ DC2-like cells will prompt further investigation into their impact on immune homeostasis, inflammation, and autoimmunity.

Mucosal Single-Cell Profiling of Crohn's-Like Disease of the Pouch Reveals Unique Pathogenesis and Therapeutic Targets.

BACKGROUND & AIMS: The pathophysiology of Crohn's-like disease of the pouch (CDP) in patients with a history of ulcerative colitis (UC) is unknown. We examined mucosal cells from patients with and without CDP using single-cell analyses. METHODS: Endoscopic samples were collected from pouch body and prepouch ileum (pouch/ileum) of 50 patients with an ileal pouch-anal anastomosis. Single-cell RNA sequencing was performed on pouch/ileal tissues of patients with normal pouch/ileum and CDP. Mass cytometry was performed on mucosal immune cells from patients with UC with normal pouch/ileum, CDP, pouchitis, and those with familial adenomatous polyposis after pouch formation. Findings were independently validated using immunohistochemistry. RESULTS: The cell populations/states in the pouch body differed from those in the prepouch ileum, likely secondary to increased microbial burden. Compared with the familial adenomatous polyposis pouch, the UC pouch was enriched in colitogenic immune cells even without inflammation. CDP was characterized by increases in T helper 17 cells, inflammatory fibroblasts, inflammatory monocytes, TREM1+ monocytes, clonal expansion of effector T cells, and overexpression of T helper 17 cells-inducing cytokine genes such as IL23, IL1B, and IL6 by mononuclear phagocytes. Ligand-receptor analysis further revealed a stromal-mononuclear phagocytes-lymphocyte circuit in CDP. Integrated analysis showed that up-regulated immune mediators in CDP were similar to those in CD and pouchitis, but not UC. Additionally, CDP pouch/ileum exhibited heightened endoplasmic reticulum stress across all major cell compartments. CONCLUSIONS: CDP likely represents a distinct entity of inflammatory bowel disease with heightened endoplasmic reticulum stress in both immune and nonimmune cells, which may become a novel diagnostic biomarker and therapeutic target for CDP.

Targeting the E3 ubiquitin ligases DCAF15 and cereblon for cancer therapy.

Small molecule-mediated inhibition of protein function is the rational behind therapeutic efficacy of the majority clinically used drugs. In order for a drug to achieve pharmacologically relevant inhibition, efficient target engagement at high selectivity and specificity is necessary to obtain the desired therapeutic effect minimizing offtarget outcomes. Majority of small molecules approaches developed so far have failed in their attempt to reach clinical efficacy because of low selectivity and low specificity in achieving close to 100 % target inhibition. Recently, approaches that directly control cellular protein levels have opened the potential to accomplish a high grade of efficacy not imaginable with traditional small-molecule inhibitors. Research in this area has just started opening avenues to effectively degrade a cellular target of choice and will soon impact clinical efficacy.

The Biology of F-box Proteins: The SCF Family of E3 Ubiquitin Ligases.

F-box proteins function as substrate adaptors for the S-phase kinase-associated protein 1 (SKP1)-cullin 1 (CUL1)-F-box protein (SCF) ubiquitin ligase complexes, which mediate the proteasomal degradation of a diverse range of regulatory proteins. 20 years since the F-box protein family has been discovered, our understanding of substrate-recognition regulation and the roles F-box proteins play in cellular processes has continued to expand. Here, we provide an introduction to the discovery and classification of F-box proteins, the overall structural assembly of SCF complexes, the varied mechanisms by which F-box proteins recognize their substrates, and the role F-box proteins play in diseases and their potentials in targeted therapies.

Effect of polyDADMAC on aggregation of clay-size particles in red mud: Implications for immobilization practices.

PolyDADMAC (PD) is a high charge density cationic polymer of diallyldimethylammonium chloride which has been recently developed as a coagulant in water purification. As PD has high affinity to fine negatively-charged colloids, it is worth to ascertain if PD can affect surface properties of clay-size particles in red mud waste and be applied to develop immobilization techniques for red mud storage areas. In the current study, a test tube method in combination with surface charge measurement was used for determination of the colloidal properties of a red mud sample under the variation of PD, soluble Al and Si, and variable pH conditions. Observations for the PD concentration range from 0.25 to 2.0 mM revealed that PD can increase surface charge and enhance aggregation or at least shift the aggregation zone to higher pH. This suggests a possible application of PD for immobilization of red mud in alkaline condition. It was also found that soluble Al and Si acted to modify the effect of PD and aggregation properties of red mud. While soluble Si supported aggregation, Al appeared as an enhancer for dispersion of red mud. It implies that development of PD-based techniques for immobilization of red mud needs to consider the effects of soluble Al and Si.

Effective sludge management: Reuse of biowaste and sewer sediments for fired bricks.

This study partially replaced the clay with sewer sludge (SS) and rice husk (RH-SS) to make fired bricks. The brick samples were examed in terms of shrinkage, water absorption, and compressive strength. Besides, they were analyzed via XRD and metal extraction to determine the heavy metal residuals in the products. The results showed that it was possible to fabricate fired bricks using sewer sludge or rice husk-blended sludge with up to 30% by weight. These brick samples complied with the technical standard for clay brick production, in which the compressive strength was more than 7.5 MPa, water absorption was from 11-16%, and the linear shrinkage was all less than 5%. The rice husk addition helped mitigate the heavy metal residuals in the bricks and leaching liquid, in which all the values were lower than the US-EPA maximum concentration of contaminants for toxicity characteristics.Implications: Previous studies have proved the possibility of mixing sewage sludge from different origins (sewage sludge, river sediment, canal sediment, sewer sediment, etc.) with clay and some wastes to make bricks. In which, mostof the studies used sewage sludge from wastewater treatment plants, very fewdealt with lake/river or sewer sediment. This study shall be the first to study the possibility of employing sewer sediments with the addition of rice husk powder to achieve two targets, including (1) the reuse of biowaste and sludge for brick fabrication and (2) the reduction of heavy metals in final calcined bricks. Different ratios of the rice-husk blended sewer sludge (RH-SS) - clay mixture shall be tested to find the optimized compositions. The results showed that it was possible to fabricate fired bricks using sewer sludge or rice husk-blended sludge with up to 30% by weight, which meant reduce 30% of clay in the brick production. The final products were proved to meet the quality standard in terms of compressive strength (more than 10 MPa), water absorption(from 11-16%), and the linear shrinkage (less than 5%). Larger scale of this study can be an evident to recommend for policy change in the waste reuse in construction field.

Effect of biowaste and construction waste additives on mechanical dewaterability of lake sediment for brick production.

Nowadays, when the zero-waste strategy is an inevitable component of the circular economy, the reuse of waste, including dredged sludges, has drawn the attention of many researchers. This study evaluated four kinds of bio-wastes (corn core powder, rice husk powder, sugarcane bagasse powder, and peanut shell powders) and two kinds of construction wastes (autoclaved aerated concrete-AAC and pavement stone) in enhancing the dewaterability of dredged sludge from the lake, in which the sludges would then be reused for brick production. The results showed that the moisture contents decreased from 62 ± 0.14% to 57 ± 1.89% after mixing and then to 35 ± 8.31% after compressing for the construction waste-blended sludge. Among the bio-wastes, the sugarcane bagasse additive performed the best at a mixing ratio of 1:3 by weight and rice husk powder worked best at a mixing ratio of 1:5 by weight. The organic matter was increased up to 80% when the bio-wastes were added, while it was decreased to 5% for the case of construction wastes. The optimum percentage of sludge in the mixture to meet all the oxide contents in the brick and energy saving shall be about 30%. The results have revealed a potentially green route for brick production with lake sediment and bio-waste/construction wastes.Implications: It is the first time the reuse of agro-wastes/construction waste was evaluated to mix with lake sediment to partly replace clay for brick production; Among the bio-wastes, the sugarcane bagasse additive performed the best at a mixing ratio of 1:3 by weight; Moisture contents decreased from 62 ± 0.14% to 57 ± 1.89% after mixing and then to 35 ± 8.31% after compressing for the blended sludge; The optimum percentage of mixed sludge, possibly replaced the clay in brick production, considering oxide contents and energy saving shall be up to 30%.

Colloidal Dynamics of Freshly Formed Iron Oxides under the Influence of Silicic Acid.

Silicic acid and soluble Fe are among the most abundant components in acid mine drainage. During the oxidation of Fe(II), the interaction between silicic acid and freshly formed Fe oxides might change the colloidal dynamics, altering surface charge properties. However, the effects of silicic acid on colloidal Fe oxides formed from acid mine drainage are not fully understood. In this work, we examined the colloidal dynamics of freshly formed Fe oxides in synthetic acid mine drainage (prepared from FeSO solution) under the effect of silicic acid as a function of changes in pH and ionic strength. The results demonstrate that through adsorption, silicic acid progressively slows oxidation and enhances the dispersion of freshly formed Fe oxides by shifting the surface charge toward more negative values. This effect was most prominent between pH 5 and 9. The current results demonstrate that silicic acid enhances the dispersion and transport of freshly formed Fe oxides and suggest that aggregation-based techniques for the treatment of Fe-rich drainage may require further consideration of this effect.