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When dysregulated, skin fibrosis can lead to a multitude of pathologies. We provide a framework for understanding the wide clinical spectrum, mechanisms, and management of cutaneous fibrosis encompassing a variety of matrix disorders, fibrohistiocytic neoplasms, injury-induced scarring, and autoimmune scleroses. Underlying such entities are common mechanistic pathways that leverage morphogenic signaling, immune activation, and mechanotransduction to modulate fibroblast function. In light of the limited array of available treatments for cutaneous fibrosis, scientific insights have opened new therapeutic and investigative avenues for conditions that still lack effective interventions. [ABSTRACT FROM AUTHOR]

Sickle cell disease (SCD) is a hereditary blood disorder characterized by abnormal hemoglobin, leading to the sickle shape of red blood cells. It has several vascular complications and the cerebrovascular ones are among the most frequent and severe both in children and in adults. This review summarizes the main neurovascular manifestations of SCD, including acute stroke, silent cerebral infarction, large-vessel diseases (moyamoya arteriopathy and aneurysms), and brain bleeding. Both epidemiology, pathophysiology, and treatment issues are addressed and prevention of cerebrovascular events, including silent cerebral infarctions, is particularly relevant in SCD patients, being associated to poor functional outcome and cognitive complaints. Transfusions and hydroxyurea are the main available therapy at the moment, but contraindications, availability, and complications might prevent their long term use, particularly in low-income countries. The role of transcranial Doppler in monitoring the patients (mainly children) is analyzed and a practical approach has been selected in order to give the main messages from the current literature for a better management of SCD patients. [ABSTRACT FROM AUTHOR]

Different ligands stabilize specific conformations of the angiotensin II type 1 receptor (AT1R) that direct distinct signaling cascades mediated by heterotrimeric G proteins or β-arrestin. These different active conformations are thought to engage distinct intracellular transducers because of differential phosphorylation patterns in the receptor C-terminal tail (the "barcode" hypothesis). Here, we identified the AT1R barcodes for the endogenous agonist AngII, which stimulates both G protein activation and β-arrestin recruitment, and for a synthetic biased agonist that only stimulates β-arrestin recruitment. The endogenous and β-arrestin–biased agonists induced two different ensembles of phosphorylation sites along the C-terminal tail. The phosphorylation of eight serine and threonine residues in the proximal and middle portions of the tail was required for full β-arrestin functionality, whereas phosphorylation of the serine and threonine residues in the distal portion of the tail had little influence on β-arrestin function. Similarly, molecular dynamics simulations showed that the proximal and middle clusters of phosphorylated residues were critical for stable β-arrestin–receptor interactions. These findings demonstrate that ligands that stabilize different receptor conformations induce different phosphorylation clusters in the C-terminal tail as barcodes to evoke distinct receptor-transducer engagement, receptor trafficking, and signaling. Editor's summary: The specific patterns of phosphorylation in the intracellular tail of a G protein–coupled receptor (GPCR) are thought to act as a barcode that determines whether G proteins are stimulated or β-arrestins are recruited. Gareri et al. investigated the role of phosphorylation barcodes in signaling by the angiotensin II type 1 receptor (AT1R). AT1R elicits both G protein activation and β-arrestin recruitment in response to the endogenous agonist AngII but stimulates only β-arrestin recruitment in response to a synthetic biased agonist. The authors identified patterns of serine and threonine phosphorylation that stabilized specific conformations of β-arrestin and were necessary for β-arrestin function. These findings demonstrate the importance of phosphorylation barcodes in determining the consequences of AT1R activation. —Annalisa M. VanHook [ABSTRACT FROM AUTHOR]

The AA6082-T6 was experimentally studied in the present research with respect to the drilling performance. Drill diameter, cutting speed and feed rate were examined, using a full factorial design. Mathematical modelling of the process was carried out using the Response Surface Methodology (RSM) as well as the Artificial Neural Network (ANN) techniques. The output results in terms of cutting force, torque and surface roughness, revealed high levels of correlation between the experimental and the predicted data. Specifically, the Mean Absolute Percentage Error (MAPE) values using RSM compared to the ones of the experiments, were equal to 2.14%, 3.49% and 6.16% for Fz, Mz and Ra respectively. The equivalent MAPE between the ANN and the experiments were found to be 2.19%, 1.82% and 2.85% accordingly. Moreover, the most significant terms were revealed, being the interaction D × f for the thrust force and the torque with contribution percentages equal to approximately 44% and 42% respectively, and the term D² for the surface roughness with 51%. The evaluation of the machining parameters, identified their significance, enabling the selection of the optimal cutting parameters, which were obtained by the desirability function, taking into account the importance of the generated surface quality and the reduction of cost. The solutions given by this approach, pointed out the Φ9 tool, coupled with Vc = 50 m/min and f = 0.15mm/rev as a well-balanced combination, whereas the Φ9.9 tool used under the same conditions, yielded the best possible surface quality (appr. 0.2 mm). [ABSTRACT FROM AUTHOR]

The stabilization of different active conformations of G protein–coupled receptors is thought to underlie the varying efficacies of biased and balanced agonists. Here, profiling the activation of signal transducers by angiotensin II type 1 receptor (AT1R) agonists revealed that the extent and kinetics of β-arrestin binding exhibited substantial ligand-dependent differences, which were lost when receptor internalization was inhibited. When AT1R endocytosis was prevented, even weak partial agonists of the β-arrestin pathway acted as full or near-full agonists, suggesting that receptor conformation did not exclusively determine β-arrestin recruitment. The ligand-dependent variance in β-arrestin translocation was much larger at endosomes than at the plasma membrane, showing that ligand efficacy in the β-arrestin pathway was spatiotemporally determined. Experimental investigations and mathematical modeling demonstrated how multiple factors concurrently shaped the effects of agonists on endosomal receptor–β-arrestin binding and thus determined the extent of functional selectivity. Ligand dissociation rate and G protein activity had particularly strong, internalization-dependent effects on the receptor–β-arrestin interaction. We also showed that endocytosis regulated the agonist efficacies of two other receptors with sustained β-arrestin binding: the V2 vasopressin receptor and a mutant β2-adrenergic receptor. In the absence of endocytosis, the agonist-dependent variance in β-arrestin2 binding was markedly diminished. Our results suggest that endocytosis determines the spatiotemporal bias in GPCR signaling and can aid in the development of more efficacious, functionally selective compounds. Editor's summary: Biased agonists of GPCRs stimulate signaling through either G proteins or β-arrestins, which is clinically relevant if one pathway is therapeutic and the other produces side effects. Tóth et al. found that the endocytosis of the angiotensin II receptor AT1R and other GPCRs determined signaling strength through the β-arrestin pathway. Blocking endocytosis elicited responses from weak β-arrestin–biased agonists that resembled those generated by full agonists. As a result, ligand efficacy in β-arrestin signaling may be determined more by spatiotemporal regulation than by the induction of different receptor conformations at the plasma membrane by distinct agonists. These findings may guide the development of GPCR-targeting drugs that more effectively produce only the desired therapeutic response. —John F. Foley [ABSTRACT FROM AUTHOR]

Background: Due to the risk of cerebral vascular injury, children and adolescents with high-risk sickle cell disease (SCD) experience neurocognitive decline over time. Haploidentical stem cell transplantation (HISCT) from human leukocyte antigen-matched sibling donors may slow or stop progression of neurocognitive changes. Objectives: The study is to determine if HISCT can ameliorate SCD-associated neurocognitive changes and prevent neurocognitive progression, determine which specific areas of neurocognitive functioning are particularly vulnerable to SCD, and determine if there are age-related differences in neurocognitive functioning over time. Methods: We performed neurocognitive and neuroimaging in SCD recipients following HISCT. Children and adolescents with high-risk SCD who received parental HISCT utilizing CD34+ enrichment and mononuclear cell (T-cell) addback following myeloimmunoablative conditioning received cognitive evaluations and neuroimaging at three time points: pre-transplant, 1 and 2 years post-transplant. Results: Nineteen participants (13.1 ± 1.2 years [3.3-20.0]) received HISCT. At 2 years post-transplant, neuroimaging and cognitive function were stable. Regarding age-related differences pre-transplantation, older children (≥13 years) had already experienced significant decreases in language functioning (p < 0.023), verbal intelligence quotient (p < 0.05), non-verbal intelligence quotient (p < 0.006), and processing speed (p < 0.05), but normalized post-HISCT in all categories. Conclusion: Thus, HISCT has the potential to ameliorate SCD-associated neurocognitive changes and prevent neurocognitive progression. Further studies are required to determine if neurocognitive performance remains stable beyond 2 years post-HISCT. Clinical trial registration: The study was conducted under an investigator IND (14359) (MSC) and registered at clinicaltrials.gov (NCT01461837). [ABSTRACT FROM AUTHOR]

Children with sickle cell disease (SCD) may experience cognitive difficulties, including slowed processing speed. Thus, we investigated if processing speed changes over time. From 1992–2001, 103 participants with SCD aged 3–16 years (n ≤ 8.99 = 45; n ≥ 9.00 = 58) completed cognitive assessments. MRI was available for 54 participants. Between 1992–2002, 58 participants consented to one or two further assessments. A repeated measures regression using linear mixed-effects modelling determined longitudinal changes in processing speed index (PSI), examining the interaction between age (continuous variable) and timepoint (i.e., assessment 1 or 3) and controlling for MRI infarct status (i.e., no infarct, silent infarct, or stroke). Those aged ≤8.99 and ≥9.00 at first assessment experienced PSI decline. Declines were most prominent for the processing speed coding subtest, with a significant interaction between timepoint and age, t(31) = 2.64, p = 0.01. This decline may reflect a developmental delay, likely due to disease progression, with slower improvements in processing speed. Although there have been significant improvements in SCD treatments, mostly in high-income countries, processing speed still remains a target; thus, incorporating clinical monitoring of processing speed may help identify delay and allow for early intervention. [ABSTRACT FROM AUTHOR]

Erythroid cells, the most prevalent cell type in blood, are one of the earliest products and permeate through the entire process of hematopoietic development in the human body, the oxygen-transporting function of which is crucial for maintaining overall health and life support. Previous investigations into erythrocyte differentiation and development have primarily focused on population-level analyses, lacking the single-cell perspective essential for comprehending the intricate pathways of erythroid maturation, differentiation, and the encompassing cellular heterogeneity. The continuous optimization of single-cell transcriptome sequencing technology, or single-cell RNA sequencing (scRNA-seq), provides a powerful tool for life sciences research, which has a particular superiority in the identification of unprecedented cell subgroups, the analyzing of cellular heterogeneity, and the transcriptomic characteristics of individual cells. Over the past decade, remarkable strides have been taken in the realm of single-cell RNA sequencing technology, profoundly enhancing our understanding of erythroid cells. In this review, we systematically summarize the recent developments in single-cell transcriptome sequencing technology and emphasize their substantial impact on the study of erythroid cells, highlighting their contributions, including the exploration of functional heterogeneity within erythroid populations, the identification of novel erythrocyte subgroups, the tracking of different erythroid lineages, and the unveiling of mechanisms governing erythroid fate decisions. These findings not only invigorate erythroid cell research but also offer new perspectives on the management of diseases related to erythroid cells., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Nonmyeloablative, matched sibling donor hematopoietic stem cell transplantation with alemtuzumab/total body irradiation (TBI) conditioning is a curative therapy with low toxicity for adults with sickle cell disease (SCD). However, relatively low donor chimerism levels and graft rejection remain important challenges. We hypothesized that adding azathioprine/hydroxyurea preconditioning will improve donor chimerism levels and reduce graft failure rate. In this prospective cohort study, we enrolled consecutive adult patients with SCD undergoing matched sibling donor transplantation at the Amsterdam UMC. Patients received azathioprine 150 mg/day and hydroxyurea 25 mg/kg/day for 3 months prior to alemtuzumab 1 mg/kg and 300 cGy TBI conditioning. Twenty patients with SCD (median age 26 years [range 19-49], 13 females) were transplanted. Median follow-up was 46.0 months (IQR 21.8-57.9). One-year overall survival and event-free survival (graft failure or death) were both 95% (95% confidence interval 86-100). Mean donor myeloid and T-cell chimerism 1-year post-transplant were 95.2% (SD ±10.6) and 67.3% (±15.3), respectively. One patient (5%) experienced graft failure without autologous regeneration, resulting in infections and death. All other patients had a corrected SCD phenotype and were able to discontinue sirolimus. Three patients were successfully treated with alemtuzumab (1 mg/kg) after the transplant because of declining donor chimerism and cytopenias to revert impending graft rejection. Toxicity was mostly related to sirolimus and alemtuzumab. One patient developed steroid-responsive grade II intestinal acute graft-versus-host disease. Collectively, preconditioning with azathioprine/hydroxyurea prior to nonmyeloablative matched sibling donor transplantation resulted in excellent event-free survival and robust donor T-cell chimerism, enabling the successful withdrawal of sirolimus. ClinicalTrials.gov: NCT05249452., (© 2024 The Authors. American Journal of Hematology published by Wiley Periodicals LLC.)

Allogeneic stem cell transplantation (Allo-SCT) is the only rapidly available curative treatment modality in patients with severe sickle cell disease (SCD). The development of reduced-toxicity myeloablative conditioning (RT-MAC) regimen and the use of partially matched family donors with post-transplantation cyclophosphamide (PT-Cy) have widened the access to Allo-SCT. Antibodies against donor-specific HLA (DSA) increase the risk of engraftment failure in HLA mismatched Allo-SCT. We report the results of five patients with SCD, whereas three with DSA, who underwent an unmanipulated haploidentical stem cell transplantation (Haplo-SCT) after a busulfan-based RT-MAC regimen with PT-Cy. To reduce the risk of engraftment failure, a sequential two courses pharmacological pre-transplant immune suppression (PTIS) phase was added prior to the conditioning regimen. All patients engrafted successfully. The procedure was well tolerated. None of the patients developed acute GVHD, whereas one developed moderate chronic GVHD. After a median follow-up of 5 years (range, 2.2-9), all patients are free of pain with excellent quality of life. Our report shows that Haplo-SCT after a RT-MAC regimen is feasible and safe with stable long-term engraftment and excellent disease control. The risk of graft failure can be abrogated by adding a PTIS phase prior to initiating the conditioning regimen., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Adoptive immunotherapy utilizing natural killer (NK) cells has demonstrated remarkable efficacy in treating hematologic malignancies. However, its clinical intervention for solid tumors is hindered by the limited expression of tumor-specific antigens. Herein, lipid-PEG conjugated hyaluronic acid (HA) materials (HA-PEG-Lipid) for the simple ex-vivo surface coating of NK cells is developed for 1) lipid-mediated cellular membrane anchoring via hydrophobic interaction and thereby 2) sufficient presentation of the CD44 ligand (i.e., HA) onto NK cells for cancer targeting, without the need for genetic manipulation. Membrane-engineered NK cells can selectively recognize CD44-overexpressing cancer cells through HA-CD44 affinity and subsequently induce in situ activation of NK cells for cancer elimination. Therefore, the surface-engineered NK cells using HA-PEG-Lipid (HANK cells) establish an immune synapse with CD44-overexpressing MIA PaCa-2 pancreatic cancer cells, triggering the "recognition-activation" mechanism, and ultimately eliminating cancer cells. Moreover, in mouse xenograft tumor models, administrated HANK cells demonstrate significant infiltration into solid tumors, resulting in tumor apoptosis/necrosis and effective suppression of tumor progression and metastasis, as compared to NK cells and gemcitabine. Taken together, the HA-PEG-Lipid biomaterials expedite the treatment of solid tumors by facilitating a sequential recognition-activation mechanism of surface-engineered HANK cells, suggesting a promising approach for NK cell-mediated immunotherapy., (© 2023 Wiley‐VCH GmbH.)

Secondary hemophagocytic lymphohistiocytosis (sHLH) has historically been defined as a cytokine storm syndrome (CSS) occurring in the setting of triggers leading to strong and dysregulated immunological activation, without known genetic predilection. However, recent studies have suggested that existing underlying genetic factors may synergize with particular diseases and/or environmental triggers (including infection, autoimmune/autoinflammatory disorder, certain biologic therapies, or malignant transformation), leading to sHLH. With the recent advances in genetic testing technology, more patients are examined for genetic variations in primary HLH (pHLH)-associated genes, including through whole exome and whole genome sequencing. This expanding genetic and genomic evidence has revealed HLH as a more complex phenomenon, resulting from specific immune challenges in patients with a susceptible genetic background. Rather than a simple, binary definition of pHLH and sHLH, HLH represents a spectrum of diseases, from a severe complication of common infections (EBV, influenza) to early onset familial diseases that can only be cured by transplantation., (© 2024. The Author(s), under exclusive license to Springer Nature Switzerland AG.)