OLFM4 modulates intestinal inflammation by promoting IL-22+ILC3 in the gut.

Group 3 innate lymphoid cells (ILC3s) play key roles in intestinal inflammation. Olfactomedin 4 (OLFM4) is highly expressed in the colon and has a potential role in dextran sodium sulfate-induced colitis. However, the detailed mechanisms underlying the effects of OLFM4 on ILC3-mediated colitis remain unclear. In this study, we identify OLFM4 as a positive regulator of IL-22+ILC3. OLFM4 expression in colonic ILC3s increases substantially during intestinal inflammation in humans and mice. Compared to littermate controls, OLFM4-deficient (OLFM4-/-) mice are more susceptible to bacterial infection and display greater resistance to anti-CD40 induced innate colitis, together with impaired IL-22 production by ILC3, and ILC3s from OLFM4-/-mice are defective in pathogen resistance. Besides, mice with OLFM4 deficiency in the RORγt compartment exhibit the same trend as in OLFM4-/-mice, including colonic inflammation and IL-22 production. Mechanistically, the decrease in IL-22+ILC3 caused by OLFM4 deficiency involves the apoptosis signal-regulating kinase 1 (ASK1)- p38 MAPK signaling-dependent downregulation of RAR-related orphan receptor gamma (RORγt) protein. The OLFM4-metadherin (MTDH) complex upregulates p38/RORγt signaling, which is necessary for IL-22+ILC3 activation. The findings indicate that OLFM4 is a novel regulator of IL-22+ILC3 and essential for modulating intestinal inflammation and tissue homeostasis.

Single-Cell RNA Sequencing Reveals Immunomodulatory Effects of Stem Cell Factor and Granulocyte Colony-Stimulating Factor Treatment in the Brains of Aged APP/PS1 Mice.

Alzheimer's disease (AD) leads to progressive neurodegeneration and dementia. AD primarily affects older adults with neuropathological changes including amyloid-beta (Aß) deposition, neuroinflammation, and neurodegeneration. We have previously demonstrated that systemic treatment with combined stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF) (SCF+G-CSF) reduces the Aß load, increases Aß uptake by activated microglia and macrophages, reduces neuroinflammation, and restores dendrites and synapses in the brains of aged APPswe/PS1dE9 (APP/PS1) mice. However, the mechanisms underlying SCF+G-CSF-enhanced brain repair in aged APP/PS1 mice remain unclear. This study used a transcriptomic approach to identify the potential mechanisms by which SCF+G-CSF treatment modulates microglia and peripheral myeloid cells to mitigate AD pathology in the aged brain. After injections of SCF+G-CSF for 5 consecutive days, single-cell RNA sequencing was performed on CD11b+ cells isolated from the brains of 28-month-old APP/PS1 mice. The vast majority of cell clusters aligned with transcriptional profiles of microglia in various activation states. However, SCF+G-CSF treatment dramatically increased a cell population showing upregulation of marker genes related to peripheral myeloid cells. Flow cytometry data also revealed an SCF+G-CSF-induced increase of cerebral CD45high/CD11b+ active phagocytes. SCF+G-CSF treatment robustly increased the transcription of genes implicated in immune cell activation, including gene sets that regulate inflammatory processes and cell migration. The expression of S100a8 and S100a9 was robustly enhanced following SCF+G-CSF treatment in all CD11b+ cell clusters. Moreover, the topmost genes differentially expressed with SCF+G-CSF treatment were largely upregulated in S100a8/9-positive cells, suggesting a well-conserved transcriptional profile related to SCF+G-CSF treatment in resident and peripherally derived CD11b+ immune cells. This S100a8/9-associated transcriptional profile contained notable genes related to pro-inflammatory and anti-inflammatory responses, neuroprotection, and Aß plaque inhibition or clearance. Altogether, this study reveals the immunomodulatory effects of SCF+G-CSF treatment in the aged brain with AD pathology, which will guide future studies to further uncover the therapeutic mechanisms.

CRISPR-Cas9n-mediated ELANE promoter editing for gene therapy of severe congenital neutropenia.

Severe congenital neutropenia (CN) is an inherited pre-leukemia bone marrow failure syndrome commonly caused by autosomal-dominant ELANE mutations (ELANE-CN). ELANE-CN patients are treated with daily injections of recombinant human granulocyte colony-stimulating factor (rhG-CSF). However, some patients do not respond to rhG-CSF, and approximately 15% of ELANE-CN patients develop myelodysplasia or acute myeloid leukemia. Here, we report the development of a curative therapy for ELANE-CN through inhibition of ELANE mRNA expression by introducing two single-strand DNA breaks at the opposing DNA strands of the ELANE promoter TATA box using CRISPR-Cas9D10A nickases-termed MILESTONE. This editing effectively restored defective neutrophil differentiation of ELANE-CN CD34+ hematopoietic stem and progenitor cells (HSPCs) in vitro and in vivo, without affecting the functions of the edited neutrophils. CRISPResso analysis of the edited ELANE-CN CD34+ HSPCs revealed on-target efficiencies of over 90%. Simultaneously, GUIDE-seq, CAST-Seq, and rhAmpSeq indicated a safe off-target profile with no off-target sites or chromosomal translocations. Taken together, ex vivo gene editing of ELANE-CN HSPCs using MILESTONE in the setting of autologous stem cell transplantation could be a universal, safe, and efficient gene therapy approach for ELANE-CN patients.

Blocking OLFM4/galectin-3 axis in placental polymorphonuclear myeloid-derived suppressor cells triggers intestinal inflammation in newborns.

Fetal growth restriction (FGR) is a major cause of premature and low-weight births, which increases the risk of necrotizing enterocolitis (NEC); however, the association remains unclear. We report a close correlation between placental polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) and NEC. Newborns with previous FGR exhibited intestinal inflammation and more severe NEC symptoms than healthy newborns. Placental PMN-MDSCs are vital regulators of fetal development and neonatal gut inflammation. Placental single-cell transcriptomics revealed that PMN-MDSCs populations and olfactomedin-4 gene (Olfm4) expression levels were significantly increased in PMN-MDSCs in later pregnancy compared to those in early pregnancy and non-pregnant females. Female mice lacking Olfm4 in myeloid cells mated with wild-type males showed FGR during pregnancy, with a decreased placental PMN-MDSCs population and expression of growth-promoting factors (GPFs) from placental PMN-MDSCs. Galectin-3 (Gal-3) stimulated the OLFM4-mediated secretion of GPFs by placental PMN-MDSCs. Moreover, GPF regulation via OLFM4 in placental PMN-MDSCs was mediated via hypoxia inducible factor-1α (HIF-1α). Notably, the offspring of mothers lacking Olfm4 exhibited intestinal inflammation and were susceptible to NEC. Additionally, OLFM4 expression decreased in placental PMN-MDSCs from pregnancies with FGR and was negatively correlated with neonatal morbidity. These results revealed that placental PMN-MDSCs contributed to fetal development and ameliorate newborn intestinal inflammation.

Stat3 Regulates Developmental Hematopoiesis and Impacts Myeloid Cell Function via Canonical and Non-Canonical Modalities.

INTRODUCTION: Signal transducer and activator of transcription (STAT) 3 is extensively involved in the development, homeostasis, and function of immune cells, with STAT3 disruption associated with human immune-related disorders. The roles ascribed to STAT3 have been assumed to be due to its canonical mode of action as an inducible transcription factor downstream of multiple cytokines, although alternative noncanonical functional modalities have also been identified. The relative involvement of each mode was further explored in relevant zebrafish models. METHODS: Genome editing with CRISPR/Cas9 was used to generate mutants of the conserved zebrafish Stat3 protein: a loss of function knockout (KO) mutant and a mutant lacking C-terminal sequences including the transactivation domain (ΔTAD). Lines harboring these mutations were analyzed with respect to blood and immune cell development and function in comparison to wild-type zebrafish. RESULTS: The Stat3 KO mutant showed perturbation of hematopoietic lineages throughout primitive and early definitive hematopoiesis. Neutrophil numbers did not increase in response to lipopolysaccharide (LPS) or granulocyte colony-stimulating factor (G-CSF) and their migration was significantly diminished, the latter correlating with abrogation of the Cxcl8b/Cxcr2 pathway, with macrophage responses perturbed. Intriguingly, many of these phenotypes were not shared by the Stat3 ΔTAD mutant. Indeed, only neutrophil and macrophage development were disrupted in these mutants with responsiveness to LPS and G-CSF maintained, and neutrophil migration actually increased. CONCLUSION: This study has identified roles for zebrafish Stat3 within hematopoietic stem cells impacting multiple lineages throughout primitive and early definitive hematopoiesis, myeloid cell responses to G-CSF and LPS and neutrophil migration. Many of these roles showed conservation, but notably several involved noncanonical modalities, providing additional insights for relevant diseases.

Expression, Purification, and Biological Evaluation of XTEN-GCSF in a Neutropenic Rat Model.

Granulocyte colony-stimulating factor (GCSF) stimulates the proliferation of neutrophils but it has low serum half-life. Therefore, the present study was done to investigate the effect of XTENylation on biological activity, pharmacokinetics, and pharmacodynamics of GCSF in a neutropenic rat model. XTEN tag was genetically fused to the N-terminal region of GCSF-encoding gene fragment and subcloned into pET28a expression vector. The cytoplasmic expressed recombinant protein was characterized through intrinsic fluorescence spectroscopy (IFS), dynamic light scattering (DLS), and size exclusion chromatography (SEC). In vitro biological activity of the XTEN-GCSF protein was evaluated on NFS60 cell line. Hematopoietic properties and pharmacokinetics were also investigated in a neutropenic rat model. An approximately 140 kDa recombinant protein was detected on SDS-PAGE. Dynamic light scattering and size exclusion chromatography confirmed the increase in hydrodynamic diameter of GCSF molecule after XTENylation. GCSF derivatives showed efficacy in proliferation of NFS60 cell line among which the XTEN-GCSF represented the lowest EC50 value (100.6 pg/ml). Pharmacokinetic studies on neutropenic rats revealed that XTEN polymer could significantly increase protein serum half-life in comparison with the commercially available GCSF molecules. PEGylated and XTENylated GCSF proteins were more effective in stimulation of neutrophils compared to the GCSF molecule alone. XTENylation of GCSF represented promising results in in vitro and in vivo studies. This approach can be a potential alternative to PEGylation strategies for increasing serum half-life of protein.

Assessment of the diagnosis, treatment, and follow-up of a group of Turkish pediatric glycogen storage disease type 1b patients with varying clinical presentations and a novel mutation.

OBJECTIVES: Glycogen storage disease (GSD) type 1b is a multisystemic disease in which immune and infectious complications are present, different from GSD type 1a. Treatment with granulocyte-colony stimulating factor (G-CSF) is often required in the management of neutropenia and inflammatory bowel disease. Recently, an alternative treatment option to G-CSF has been preferred, like empagliflozin. To report on the demographics, genotype, clinical presentation, management, and complications of pediatric patients with glycogen storage disease type 1b (GSD 1b). METHODS: A retrospective analysis of the clinical course of eight patients with GSD type 1b whose diagnosis was confirmed by molecular testing. RESULTS: The mean age at referral was four months. The diagnosis of GSD 1b was based on clinical and laboratory findings and supported by genetic studies. One patient presented with an atypical clinical finding in the form of hydrocephalus at the time of first admission. The first symptom was abscess formation on the scalp due to neutropenia in another patient. Other patients had hypoglycemia at the time of admission. All patients presented suffered from neutropenia, which was managed with G-CSF, except one. Hospitalizations for infections were frequent. One patient developed chronic diarrhea and severe infections, which have been brought under control with empagliflozin. CONCLUSIONS: Neutropenia is an essential finding in GSD 1b and responsible for complications. The coexistence of hypoglycemia and neutropenia should bring to mind GSD 1b. Empagliflozin can be a treatment option for neutropenia, which is resistant to G-CSF treatment.

Gata2 noncoding genetic variation as a determinant of hematopoietic stem/progenitor cell mobilization efficiency.

Germline genetic variants alter the coding and enhancer sequences of GATA2, which encodes a master regulator of hematopoiesis. The conserved murine Gata2 enhancer (+9.5) promotes hematopoietic stem cell (HSC) genesis during embryogenesis. Heterozygosity for a single-nucleotide Ets motif variant in the human enhancer creates a bone marrow failure and acute myeloid leukemia predisposition termed GATA2 deficiency syndrome. The homozygous murine variant attenuates chemotherapy- and transplantation-induced hematopoietic regeneration, hematopoietic stem and progenitor cell (HSPC) response to inflammation, and HSPC mobilization with the therapeutic mobilizer granulocyte colony-stimulating factor (G-CSF). Because a Gata2 +9.5 variant attenuated G-CSF-induced HSPC expansion and mobilization, and HSC transplantation therapies require efficacious mobilization, we tested whether variation affects mechanistically distinct mobilizers or only those operating through select pathways. In addition to affecting G-CSF activity, Gata2 variation compromised IL-8/CXCR2- and VLA-4/VCAM1-induced mobilization. Although the variation did not disrupt HSPC mobilization mediated by plerixafor, which functions through CXCR4/CXCL12, homozygous and heterozygous variation attenuated mobilization efficacy of the clinically used plerixafor/G-CSF combination. The influence of noncoding variation on HSPC mobilization efficacy and function is important clinically because comprehensive noncoding variation is not commonly analyzed in patients. Furthermore, our mobilization-defective system offers unique utility for elucidating fundamental HSPC mechanisms.

Molecular and functional characterization of two granulocyte colony stimulating factors in goldfish (Carassius auratus L.).

Granulocyte colony-stimulating factor (GCSF) is a member of the hematopoietic growth factor family that acts primarily on neutrophils and neutrophilic precursors to promote cell proliferation and differentiation. Although multiple GCSF genes have been found in teleosts, knowledge of their functions during fish hematopoietic development is still limited. Here, we report for the first time the molecular and functional characterization of two goldfish GCSFs (gfGCSF-a and gfGCSF-b). The open reading frame (ORF) of the gfGCSF-a and gfGCSF-b cDNA transcript consisted respectively of 624 bp and 678 bp with its ORF encoding 207 and 225 amino acids (aa), with a 17 aa signal peptide for each gene and a conserved domain of the IL-6 superfamily. Treatment of goldfish head kidney leukocytes (HKLs) with LPS increased gfGCSF-a and gfGCSF-b mRNA expression levels, also exposure of HKLs to either heat-killed or live A. hydrophila, induced transcriptional upregulation of gfGCSF-a and gfGCSF-b levels. Recombinant gfGCSF-a and gfGCSF-b protein (rgGCSF-a and rgGCSF-b) induced a dose-dependent production of TNFα and IL-1ß from goldfish neutrophils. In vitro experiments showed rgGCSF-a and rgGCSF-b differentially promoted the proliferation and differentiation of leukocytes in goldfish. Furthermore, treatment of HKLs with rgGCSF-a showed significant upregulation of mRNA levels of the hematopoietic transcription factor GATA2, Runx1, MafB, and cMyb, while gfGCSF-b induces not only all four transcriptional factors mentioned above but also CEBPα. Our results indicate that goldfish GCSF-a and GCSF-b are important regulators of neutrophil proliferation and differentiation, which could stimulate different stages and lineages of hematopoiesis.

Hematologic toxicities of chemotherapy in breast and ovarian cancer patients carrying BRCA1/BRCA2 germline pathogenic variants. A single center experience and review of the literature.

BRCA1 and BRCA2 play a central role in DNA repair and their germline pathogenic variants (gBRCA) confer a high risk for developing breast and ovarian cancer. Standard chemotherapy regimens for these cancers include DNA-damaging agents. We hypothesized that gBRCA carriers might be at higher risk of developing chemotherapy-related hematologic toxicity and therapy-related myeloid neoplasms (t-MN). We conducted a retrospective study of women newly diagnosed with invasive breast or ovarian cancer who were screened for gBRCA1/gBRCA2 at Geneva University Hospitals. All patients were treated with (neo-)adjuvant chemotherapy. We evaluated acute hematologic toxicities by analyzing the occurrence of febrile neutropenia and severe neutropenia (grade 4) at day 7-14 of the first cycle of chemotherapy and G-CSF use during the entire chemotherapy regimen. Characteristics of t-MN were collected. We reviewed medical records from 447 patients: 58 gBRCA1 and 40 gBRCA2 carriers and 349 non-carriers. gBRCA1 carriers were at higher risk of developing severe neutropenia (32% vs. 14.5%, p = 0.007; OR = 3.3, 95% CI [1.6-7], p = 0.001) and of requiring G-CSF for secondary prophylaxis (58.3% vs. 38.2%, p = 0.011; OR = 2.5, 95% CI [1.4-4.8], p = 0.004). gBRCA2 carriers did not show increased acute hematologic toxicities. t-MN were observed in 2 patients (1 gBRCA1 and one non-carrier). Our results suggested an increased acute hematologic toxicity upon exposure to chemotherapy for breast and ovarian cancer among gBRCA1 but not gBRCA2 carriers. A deeper characterization of t-MN is warranted with the recent development of PARP inhibitors in frontline therapy in gBRCA breast and ovarian cancer.

Olfactomedin 4 associates with expression of differentiation markers but not with properties of cancer stemness, EMT nor metastatic spread in colorectal cancer.

Tumor stem cells play a pivotal role in carcinogenesis and metastatic spread in colorectal cancer (CRC). Olfactomedin 4 (OLFM4) is co-expressed with the established stem cell marker leucine-rich repeat-containing G protein-coupled receptor 5 at the bottom of intestinal crypts and has been suggested as a surrogate for cancer stemness and a biomarker in gastrointestinal tumors associated with prognosis. Therefore, it was the aim of the present study to clarify whether OLFM4 is involved in carcinogenesis and metastatic spread in CRC. We used a combined approach of functional assays using forced OLFM4 overexpression in human CRC cell lines, xenograft mice, and an immunohistochemical approach using patient tissues to investigate the impact of OLFM4 on stemness, canonical Wnt signaling, properties of metastasis and differentiation as well as prognosis. OLFM4 expression correlated weakly with tumor grade in one patient cohort (metastasis collection: p = 0.05; pooled analysis of metastasis collection and survival collection: p = 0.19) and paralleled the expression of differentiation markers (FABP2, MUC2, and CK20) (p = 0.002) but did not correlate with stemness-associated markers. Further analyses in CRC cells lines as well as xenograft mice including forced overexpression of OLFM4 revealed that OLFM4 neither altered the expression of markers of stemness nor epithelial-mesenchymal transition, nor did OLFM4 itself drive proliferation, migration, or colony formation, which are all prerequisites of carcinogenesis and tumor progression. In line with this, we found no significant correlation between OLFM4 expression, metastasis, and patient survival. In summary, expression of OLFM4 in human CRC seems to be characteristic of differentiation marker expression in CRC but is not a driver of carcinogenesis nor metastatic spread.

Human neutrophil development and functionality are enabled in a humanized mouse model.

Mice with a functional human immune system serve as an invaluable tool to study the development and function of the human immune system in vivo. A major technological limitation of all current humanized mouse models is the lack of mature and functional human neutrophils in circulation and tissues. To overcome this, we generated a humanized mouse model named MISTRGGR, in which the mouse granulocyte colony-stimulating factor (G-CSF) was replaced with human G-CSF and the mouse G-CSF receptor gene was deleted in existing MISTRG mice. By targeting the G-CSF cytokine-receptor axis, we dramatically improved the reconstitution of mature circulating and tissue-infiltrating human neutrophils in MISTRGGR mice. Moreover, these functional human neutrophils in MISTRGGR are recruited upon inflammatory and infectious challenges and help reduce bacterial burden. MISTRGGR mice represent a unique mouse model that finally permits the study of human neutrophils in health and disease.

Cytokine profile of human limbal myofibroblasts: Key players in corneal antiviral response.

BACKGROUND: Corneal transparency may be compromised by viral infections causing corneal scarring, edema, and neovascularization. Ocular injury results from collateral damage induced by exacerbated immune response in corneal stroma. Myofibroblasts play a key role in this process by producing a disorganized extracellular matrix and inflammatory mediators. However, the immune response profile of myofibroblasts during viral infections is still under study. The aim of this work was to analyze the cytokine profile of human limbal myfibroblasts (HLMs) stimulated with the double-stranded RNA analog polyinosinic:polycytidylic acid (poly I:C) and to identify their signaling pathways. METHODS: HLMs were isolated from cadaveric sclera-corneal rims and stimulated with poly I:C (10 µg/ml) for 12 h. The secretion of 36 cytokines was measured using the Human Cytokine Array Panel A. The secretion of IFN-ß was quantified by ELISA. The expression of pattern recognition receptors (PRRs) such as TLR3, RIG-1 and MDA5 were analyzed by western blot assays. Furthermore, translocation of the nuclear factors NF-κB, IRF3, and IRF7 was assessed by fluorescence staining. In addition, the differentially expressed cytokines were analyzed using the Core Analysis Tool of the Ingenuity Pathway Analysis IPA software. RESULTS: HLMs stimulated with poly I:C increased (fold change > 2) the secretion of G-CSF, sTREM-1, CXCL1, CCL1, CXCL8, CXCL10, CXCL11, CCL2, CCL5, IL-13, IL-6, IL-1ra, and IFN-ß compared with HLMs under basal conditions. Poly I:C stimulation also induced the expression of RIG-1 (p < 0.001), but the expression of TLR3 and MDA5 was unmodified. Finally, HLMs increased nuclear translocation of NF-κB, IRF3, and IRF7 after poly I:C stimulation. Bioinformatic analysis identified canonical signaling pathways associated with cell adhesion and diapedesis, chemokine signaling, and activation of IRFs by cytosolic pattern recognition receptors. CONCLUSIONS: These results demonstrate that HLMs secrete cytokines involved in immune cell activation and chemotaxis. The data suggest a key role for HLMs during viral infections in cornea and extend our knowledge about the signaling pathways they trigger.

[Congenital neutropenia type IV: case report]. / Neutropenia congénita de tipo IV: reporte de un caso.

Severe congenital neutropenia (SCN) is a heterogeneous disease whose more common feature is an absolute neutrophil count less than 0.5 x 109/l. It presents great genetic heterogeneity. Autosomal dominant inherited mutations of the elastase 2 gene (ELA2) represent the most common etiology. The first choice treatment is the administration of granulocyte colony stimulating factor. Patients with SCN develop severe infections early in life. We present a patient who associated SCN to a peculiar phenotype, characterized by triangular facies, retromicrognathia, prominent venous pattern in the lower limbs, atrial septal defect and poor weight progress, in whom a deficiency of the enzyme glucose 6 phosphate dehydrogenase, Neutropenia congénita de tipo IV: reporte de un caso Congenital neutropenia type IV: case report a catalytic subunit 3 (G6PC3), was diagnosed. Despite the infrequency of this mutation as the origin of SCN (2%), its knowledge becomes important because the coexistence of the characteristic phenotype and SCN guides the request for the genetic study that allows reaching the diagnosis.

La neutropenia congénita grave (NCG) es una entidad heterogénea cuya característica común es un recuento absoluto de neutrófilos inferior a 0,5 x 109/l. Presenta gran heterogeneidad genética, las mutaciones más frecuentes son las del gen de la elastasa 2 (ELA 2). El tratamiento de primera elección es la administración de factor estimulador de colonias de granulocitos. Los pacientes con NCG presentan infecciones graves en etapas tempranas de la vida. Se presenta una paciente con NCG asociada a fenotipo peculiar con facies triangular, retromicrognatia, patrón venoso prominente en miembros inferiores, comunicación interauricular y mal progreso ponderal, en quien se diagnosticó déficit de la enzima glucosa 6 fosfato deshidrogenasa, subunidad catalítica 3 (G6PC3). A pesar de lo infrecuente de esta mutación como causa de NCG (2 %), su conocimiento cobra importancia porque la coexistencia del fenotipo característico con una NCG orienta en la solicitud del estudio genético que permite arribar al diagnóstico.

Neutropenia congénita de tipo IV: reporte de un caso / Congenital neutropenia type IV: case report

La neutropenia congénita grave (NCG) es una entidad heterogénea cuya característica común es un recuento absoluto de neutrófilos inferior a 0,5 x 10 9/l. Presenta gran heterogeneidad genética, las mutaciones más frecuentes son las del gen de la elastasa 2 (ELA 2). El tratamiento de primera elección es la administración de factor estimulador de colonias de granulocitos. Los pacientes con NCG presentan infecciones graves en etapas tempranas de la vida. Se presenta una paciente con NCG asociada a fenotipo peculiar con facies triangular, retromicrognatia, patrón venoso prominente en miembros inferiores, comunicación interauricular y mal progreso ponderal, en quien se diagnosticó déficit de la enzima glucosa 6 fosfato deshidrogenasa, subunidad catalítica 3 (G6PC3). A pesar de lo infrecuente de esta mutación como causa de NCG (2 %), su conocimiento cobra importancia porque la coexistencia del fenotipo característico con una NCG orienta en la solicitud del estudio genético que permite arribar al diagnóstico.

Severe congenital neutropenia (SCN) is a heterogeneous disease whose more common feature is an absolute neutrophil count less than 0.5 x 10 9/l. It presents great genetic heterogeneity. Autosomal dominant inherited mutations of the elastase 2 gene (ELA2) represent the most common etiology. The first choice treatment is the administration of granulocyte colony stimulating factor. Patients with SCN develop severe infections early in life. We present a patient who associated SCN to a peculiar phenotype, characterized by triangular facies, retromicrognathia, prominent venous pattern in the lower limbs, atrial septal defect and poor weight progress, in whom a deficiency of the enzyme glucose 6 phosphate dehydrogenase, a catalytic subunit 3 (G6PC3), was diagnosed. Despite the infrequency of this mutation as the origin of SCN (2%), its knowledge becomes important because the coexistence of the characteristic phenotype and SCN guides the request for the genetic study that allows reaching the diagnosis.

Alternatively spliced CSF3R isoforms in SRSF2 P95H mutated myeloid neoplasms.

Alternatively spliced colony stimulating factor 3 receptor (CSF3R) isoforms Class III and Class IV are observed in myelodysplastic syndromes (MDS), but their roles in disease remain unclear. We report that the MDS-associated splicing factor SRSF2 affects the expression of Class III and Class IV isoforms and perturbs granulopoiesis. Add-back of the Class IV isoform in Csf3r-null mouse progenitor cells increased granulocyte progenitors with impaired neutrophil differentiation, while add-back of the Class III produced dysmorphic neutrophils in fewer numbers. These CSF3R isoforms were elevated in patients with myeloid neoplasms harboring SRSF2 mutations. Using in vitro splicing assays, we confirmed increased Class III and Class IV transcripts when SRSF2 P95 mutations were co-expressed with the CSF3R minigene in K562 cells. Since SRSF2 regulates splicing partly by recognizing exonic splicing enhancer (ESE) sequences on pre-mRNA, deletion of either ESE motifs within CSF3R exon 17 decreased Class IV transcript levels without affecting Class III. CD34+ cells expressing SRSF2 P95H showed impaired neutrophil differentiation in response to G-CSF and was accompanied by increased levels of Class IV. Our findings suggest that SRSF2 P95H promotes Class IV splicing by binding to key ESE sequences in CSF3R exon 17, and that SRSF2, when mutated, contributes to dysgranulopoiesis.

G-CSF Receptor Deletion Amplifies Cortical Bone Dysfunction in Mice With STAT3 Hyperactivation in Osteocytes.

Bone strength is determined by the structure and composition of its thickened outer shell (cortical bone), yet the mechanisms controlling cortical consolidation are poorly understood. Cortical bone maturation depends on SOCS3-mediated suppression of IL-6 cytokine-induced STAT3 phosphorylation in osteocytes, the cellular network embedded in bone matrix. Because SOCS3 also suppresses granulocyte-colony-stimulating factor receptor (G-CSFR) signaling, we here tested whether global G-CSFR (Csf3r) ablation altereed bone structure in male and female mice lacking SOCS3 in osteocytes, (Dmp1Cre :Socs3f/f mice). Dmp1Cre :Socs3f/f :Csf3r-/- mice were generated by crossing Dmp1Cre :Socs3f/f mice with Csf3r-/- mice. Although G-CSFR is not expressed in osteocytes, Csf3r deletion further delayed cortical consolidation in Dmp1Cre :Socs3f/f mice. Micro-CT images revealed extensive, highly porous low-density bone, with little true cortex in the diaphysis, even at 26 weeks of age; including more low-density bone and less high-density bone in Dmp1Cre :Socs3f/f :Csf3r-/- mice than controls. By histology, the area where cortical bone would normally be found contained immature compressed trabecular bone in Dmp1Cre :Socs3f/f :Csf3r-/- mice and greater than normal levels of intracortical osteoclasts, extensive new woven bone formation, and the presence of more intracortical blood vessels than the already high levels observed in Dmp1Cre :Socs3f/f controls. qRT-PCR of cortical bone from Dmp1Cre :Socs3f/f :Csf3r-/- mice also showed more than a doubling of mRNA levels for osteoclasts, osteoblasts, RANKL, and angiogenesis markers. The further delay in cortical bone maturation was associated with significantly more phospho-STAT1 and phospho-STAT3-positive osteocytes, and a threefold increase in STAT1 and STAT3 target gene mRNA levels, suggesting G-CSFR deletion further increases STAT signaling beyond that of Dmp1Cre :Socs3f/f bone. G-CSFR deficiency therefore promotes STAT1/3 signaling in osteocytes, and when SOCS3 negative feedback is absent, elevated local angiogenesis, bone resorption, and bone formation delays cortical bone consolidation. This points to a critical role of G-CSF in replacing condensed trabecular bone with lamellar bone during cortical bone formation. © 2022 American Society for Bone and Mineral Research (ASBMR).

Combination regimen of granulocyte colony-stimulating factor and recombinant human thrombopoietin improves the curative effect on elderly patients with leukemia through inducing pyroptosis and ferroptosis of leukemia cells.

Leukemia ranks as the one of most common causes of death from tumor. 51.4% of patients with leukemia are over 65 years old. However, the median overall survival (OS) of elderly leukemia patients is less than one year. It is urgent to explore more effective treatments for elderly patients with leukemia. Our recent prospective phase II single-arm study has revealed that combination regimen of granulocyte colony-stimulating factor (G-CSF) and recombinant human thrombopoietin (rhTPO) could improve the curative effect on elderly patients with leukemia, yet the precise mechanism remains unknown. This study demonstrated that combination of G-CSF and rhTPO showed greater effect on suppressing leukemia growth than G-CSF or rhTPO alone in vitro and in vivo. Mechanistically, G-CSF induced pyroptosis through ELANE in leukemia cells. Besides, rhTPO triggered ferroptosis by EP300 in leukemia cells. Moreover, rhTPO suppressed glutathione peroxidase 4 (GPX4) expression to induce ferroptosis through blocking the interaction between EP300 and GPX4 gene promoter via associating with EP300. In summary, this study illuminated that combination regimen of G-CSF and rhTPO improved the curative effect on elderly patients with leukemia through inducing pyroptosis and ferroptosis of leukemia cells. Therefore, our results provided a theoretical basis for combination regimen of G-CSF and rhTPO treating leukemia and potential therapeutic targets for leukemia.

A topological refactoring design strategy yields highly stable granulopoietic proteins.

Protein therapeutics frequently face major challenges, including complicated production, instability, poor solubility, and aggregation. De novo protein design can readily address these challenges. Here, we demonstrate the utility of a topological refactoring strategy to design novel granulopoietic proteins starting from the granulocyte-colony stimulating factor (G-CSF) structure. We change a protein fold by rearranging the sequence and optimising it towards the new fold. Testing four designs, we obtain two that possess nanomolar activity, the most active of which is highly thermostable and protease-resistant, and matches its designed structure to atomic accuracy. While the designs possess starkly different sequence and structure from the native G-CSF, they show specific activity in differentiating primary human haematopoietic stem cells into mature neutrophils. The designs also show significant and specific activity in vivo. Our topological refactoring approach is largely independent of sequence or structural context, and is therefore applicable to a wide range of protein targets.

Granulocyte Colony-Stimulating Factor Mediated Regulation of Early Myeloid Cells in Zebrafish.

BACKGROUND: Colony-stimulating factor 3 (CSF3), more commonly known as granulocyte colony-stimulating factor (G-CSF), acts via a specific cell surface receptor CSF3R (or G-CSFR) to regulate hematopoiesis, with a particularly key role in the myeloid cell lineage where it impacts the development and function of neutrophilic granulocytes. Zebrafish possess a conserved CSF3R homologue, Csf3r, which is involved in both steady-state and emergency myelopoiesis, as well as regulating early myeloid cell migration. Two CSF3 proteins have been identified in zebrafish, Csf3a and Csf3b. METHODS: This study investigated the roles of the Csf3a and Csf3b ligands as well as the downstream Janus kinase (JAK) and phosphatidylinositol 3-kinase (PI3K) pathways in mediating the effects of Csf3r in early myeloid cell development and function using gene knockdown and pharmacologic approaches. RESULTS: This study revealed that both Csf3a and Csf3b contribute to the developmental and emergency production of early myeloid cells, but Csf3a is responsible for the developmental migration of early neutrophils whereas Csf3b plays the major role in their wounding-induced migration, differentially participated in these responses, as did several downstream signaling pathways. Both JAK and PI3K signaling were required for developmental production and migration of early myeloid cells, but PI3K signaling was required for emergency production and initial migration in response to wounding, while JAK signaling mediated retention at the site of wounding. CONCLUSIONS: This study has revealed both distinct and overlapping functions for Csf3a and Csf3b and the downstream JAK and PI3K signaling pathways in early myeloid cell production and function.