Interactions among HCLS1, HAX1 and LEF-1 proteins are essential for G-CSF-triggered granulopoiesis

Emerging roles of MITF as a crucial regulator of immunity

Microphthalmia-associated transcription factor (MITF), a basic helix-loop-helix leucine zipper transcription factor (bHLH-Zip), has been identified as a melanocyte-specific transcription factor and plays a critical role in melanocyte survival, differentiation, function, proliferation and pigmentation. Although numerous studies have explained the roles of MITF in melanocytes and in melanoma development, the function of MITF in the hematopoietic or immune system-beyond its function in melanin-producing cells-is not yet fully understood. However, there is convincing and increasing evidence suggesting that MITF may play multiple important roles in immune-related cells. Therefore, this review is focused on recent advances in elucidating novel functions of MITF in cancer progression and immune responses to cancer. In particular, we highlight the role of MITF as a central modulator in the regulation of immune responses, as elucidated in recent studies.

Congenital neutropenia: From lab bench to clinic bedside and back

Neutropenia is a hematological condition characterized by a decrease in absolute neutrophil count (ANC) in peripheral blood, typically classified in adults as mild (1-1.5 × 109/L), moderate (0.5-1 × 109/L), or severe (< 0.5 × 109/L). It can be categorized into two types: congenital and acquired. Congenital severe chronic neutropenia (SCN) arises from mutations in various genes, with different inheritance patterns, including autosomal recessive, autosomal dominant, and X-linked forms, often linked to mitochondrial diseases. The most common genetic cause is alterations in the ELANE gene. Some cases exist as non-syndromic neutropenia within the SCN spectrum, where genetic origins remain unidentified. The clinical consequences of congenital neutropenia depend on granulocyte levels and dysfunction. Infants with this condition often experience recurrent bacterial infections, with approximately half facing severe infections within their first six months of life. These infections commonly affect the respiratory system, digestive tract, and skin, resulting in symptoms like fever, abscesses, and even sepsis. The severity of these symptoms varies, and the specific organs and systems affected depend on the genetic defect. Congenital neutropenia elevates the risk of developing acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS), particularly with certain genetic variants. SCN patients may acquire CSF3R and RUNX1 mutations, which can predict the development of leukemia. It is important to note that high-dose granulocyte colony-stimulating factor (G-CSF) treatment may have the potential to promote leukemogenesis. Treatment for neutropenia involves antibiotics, drugs that boost neutrophil production, or bone marrow transplants. Immediate treatment is essential due to the heightened risk of severe infections. In severe congenital or cyclic neutropenia (CyN), the primary therapy is G-CSF, often combined with antibiotics. The G-CSF dosage is gradually increased to normalize neutrophil counts. Hematopoietic stem cell transplants are considered for non-responders or those at risk of AML/MDS. In cases of WHIM syndrome, CXCR4 inhibitors can be effective. Future treatments may involve gene editing and the use of the diabetes drug empagliflozin to alleviate neutropenia symptoms.

HAX1: A versatile, intrinsically disordered regulatory protein

HAX1 is a relatively small, ubiquitously expressed, predominantly mitochondrial, intrinsically disordered protein. It has been implicated in the regulation of apoptosis, cell migration, calcium cycling, proteostasis, angiogenesis, autophagy and translation. A wide spectrum of functions, numerous interactions and still elusive molecular mechanisms of action make HAX1 an intriguing subject of research. Moreover, HAX1 is involved in the pathogenesis of diseases; its deficiency leads to neutropenia and its overexpression is associated with cancer. In this review we aim to describe the characteristics of HAX1 gene and protein, and comprehensively discuss its multiple functions, highlighting the emerging role of HAX1 in protection from stress and apoptosis through maintaining cellular proteostasis and homeostasis.

Identification and characterization of odorant receptors in Plutella xylostella antenna response to 2,3-dimethyl-6-(1-hydroxy)-pyrazine

Diamondback moth (Plutella xylostella), a worldwide migratory pest that is developing strong resistance to various chemical insecticides. It has been determined that four natural pyrazines isolated from Allium tuberosum showed significant repellent activity to P. xylostella, but the molecular target still unknown. In the present study, a novel synthetic route for 2,3-dimethyl-6-(1-hydroxy)-pyrazine which has the most significant repellent activity with a purity of 90.60% was established. Simultaneously, the bioassay result declared that the repellent grade was IV at a dosage of 0.01 mg which was the same as to the published data. Transcriptomics analysis detected 1643 upregulated and 3837 downregulated genes in P. xylostella antennae following this pyrazine exposure. Then, 2142 differentially expressed genes were annotated using Gene Ontology and 2757 genes were annotated by Kyoto Encyclopedia of Genes and Genomes. Moreover, this procedure identified 84 odour perception-related genes, 58 odorant receptor (OR) genes including 57 conventional ORs and the odorant receptor co-receptor (Orco, atypical odorant receptor) gene, and 26 odorant-binding protein (OBP) genes. Based on quantitative real time PCR (RT-qPCR) and differential expression results, 9 OR genes including the Orco were cloned and characterised. In summary, this study provides important basis for the utilization of pyrazines as the main active ingredients or lead compounds to developing new botanical pesticides, which will reduce application of chemical pesticides and postpone the development of resistance.

HAX1-related congenital neutropenia: Long-term observation in paediatric and adult patients enrolled in the European branch of the Severe Chronic Neutropenia International Registry (SCNIR)

HAX1-related congenital neutropenia (HAX1-CN) is a rare autosomal recessive disorder caused by pathogenic variants in the HAX1 gene. HAX1-CN patients suffer from bone marrow failure as assessed by a maturation arrest of the myelopoiesis revealing persistent severe neutropenia from birth. The disorder is strongly associated with severe bacterial infections and a high risk of developing myelodysplastic syndrome or acute myeloid leukaemia. This study aimed to describe the long-term course of the disease, the treatment, outcome and quality of life in patients with homozygous HAX1 mutations reported to the European branch of the Severe Chronic Neutropenia International Registry. We have analysed a total of 72 patients with different types of homozygous (n = 68), compound heterozygous (n = 3), and digenic (n = 1) HAX1 mutations. The cohort includes 56 paediatric (<18 years) and 16 adult patients. All patients were initially treated with G-CSF with a sufficient increase in absolute neutrophil counts. Twelve patients required haematopoietic stem cell transplantation for leukaemia (n = 8) and non-leukaemic indications (n = 4). While previous genotype-phenotype reports documented a striking correlation between two main transcript variants and clinical neurological phenotypes, our current analysis reveals novel mutation subtypes and clinical overlaps between all genotypes including severe secondary manifestations, e.g., high incidence of secondary ovarian insufficiency.

High intratumoral plasma cells content in primary prostate cancer defines a subset of tumors with potential susceptibility to immune-based treatments

BACKGROUND

Data on advanced prostate cancer (PCa) suggest more prior systemic therapies might reduce tumor immune responsiveness. In treatment-naïve primary PCa, recent work correlated intratumoral plasma cell content with enhanced tumor immune-responsiveness. We sought to identify features of localized PCa at a high risk of recurrence following local treatment with high plasma cell content to help focus future immune-based neoadjuvant trials.

METHODS

We performed retrospective analyses of molecular profiles from three independent cohorts of over 1300 prostate tumors. We used Wilcoxon Rank Sum to compare molecular pathways between tumors with high and low intratumoral plasma cell content and multivariable Cox proportional hazards regression analyses to assess metastasis-free survival.

RESULTS

We validated an expression-based signature for intratumoral plasma cell content in 113 primary prostate tumors with both RNA-expression data and digital image quantification of CD138+ cells (plasma cell marker) based on immunohistochemisty. The signature showed castration-resistant tumors (n = 101) with more prior systemic therapies contained lower plasma cell content. In high-grade primary PCa, tumors with high plasma cell content were associated with increased predicted response to immunotherapy and decreased response to androgen-deprivation therapy. Master regulator analyses identified upregulated transcription factors implicated in immune (e.g. SKAP1, IL-16, and HCLS1), and B-cell activity (e.g. VAV1, SP140, and FLI-1) in plasma cell-high tumors. Master regulators overactivated in tumors with low plasma cell content were associated with shorter metastasis-free survival following radical prostatectomy.

CONCLUSIONS

Markers of plasma cell activity might be leveraged to augment clinical trial targeting and selection and better understand the potential for immune-based treatments in patients with PCa at a high risk of recurrence following local treatment.

Novel Insights into the Role of Kras in Myeloid Differentiation: Engaging with Wnt/β-Catenin Signaling

Cells of the HL-60 myeloid leukemia cell line can be differentiated into neutrophil-like cells by treatment with dimethyl sulfoxide (DMSO). The molecular mechanisms involved in this differentiation process, however, remain unclear. This review focuses on the differentiation of HL-60 cells. Although the Ras proteins, a group of small GTP-binding proteins, are ubiquitously expressed and highly homologous, each has specific molecular functions. Kras was shown to be essential for normal mouse development, whereas Hras and Nras are not. Kras knockout mice develop profound hematopoietic defects, indicating that Kras is required for hematopoiesis in adults. The Wnt/β-catenin signaling pathway plays a crucial role in regulating the homeostasis of hematopoietic cells. The protein β-catenin is a key player in the Wnt/β-catenin signaling pathway. A great deal of evidence shows that the Wnt/β-catenin signaling pathway is deregulated in malignant tumors, including hematological malignancies. Wild-type Kras acts as a tumor suppressor during DMSO-induced differentiation of HL-60 cells. Upon DMSO treatment, Kras translocates to the plasma membrane, and its activity is enhanced. Inhibition of Kras attenuates CD11b expression. DMSO also elevates levels of GSK3β phosphorylation, resulting in the release of unphosphorylated β-catenin from the β-catenin destruction complex and its accumulation in the cytoplasm. The accumulated β-catenin subsequently translocates into the nucleus. Inhibition of Kras attenuates Lef/Tcf-sensitive transcription activity. Thus, upon treatment of HL-60 cells with DMSO, wild-type Kras reacts with the Wnt/β-catenin pathway, thereby regulating the granulocytic differentiation of HL-60 cells. Wild-type Kras and the Wnt/β-catenin signaling pathway are activated sequentially, increasing the levels of expression of C/EBPα, C/EBPε, and granulocyte colony-stimulating factor (G-CSF) receptor.

Extensive Adaptive Variation in Gene Expression within and between Closely Related Horseshoe Bats (Chiroptera, Rhinolophus) Revealed by Three Organs

In the process of species differentiation and adaption, the relative influence of natural selection on gene expression variation often remains unclear (especially its impact on phenotypic divergence). In this study, we used differentially expressed genes from brain, cochlea, and liver samples collected from two species of bats to determine the gene expression variation forced by natural selection when comparing at the interspecific (Rhinolophus siamensis and R. episcopus episcopus) and the intraspecific (R. e. episcopus and R. episcopus spp.) levels. In both cases, gene expression variation was extensively adaptive (>66.0%) and mainly governed by directional selection, followed by stabilizing selection, and finally balancing selection. The expression variation related to acoustic signals (resting frequency, RF) and body size (forearm length, FA) was also widely governed by natural selection (>69.1%). Different functional patterns of RF- or FA-related adaptive expression variation were found between the two comparisons, which manifested as abundant immune-related regulations between subspecies (indicating a relationship between immune response and phenotypic adaption). Our study verifies the extensive adaptive expression variation between both species and subspecies and provides insight into the effects of natural selection on species differentiation and adaptation as well as phenotypic divergence at the expression level.

A review of granulocyte colony-stimulating factor receptor signaling and regulation with implications for cancer

Granulocyte colony-stimulating factor receptor (GCSFR) is a critical regulator of granulopoiesis. Studies have shown significant upregulation of GCSFR in a variety of cancers and cell types and have recognized GCSFR as a cytokine receptor capable of influencing both myeloid and non-myeloid immune cells, supporting pro-tumoral actions. This systematic review aims to summarize the available literature examining the mechanisms that control GCSFR signaling, regulation, and surface expression with emphasis on how these mechanisms may be dysregulated in cancer. Experiments with different cancer cell lines from breast cancer, bladder cancer, glioma, and neuroblastoma are used to review the biological function and underlying mechanisms of increased GCSFR expression with emphasis on actions related to tumor proliferation, migration, and metastasis, primarily acting through the JAK/STAT pathway. Evidence is also presented that demonstrates a differential physiological response to aberrant GCSFR signal transduction in different organs. The lifecycle of the receptor is also reviewed to support future work defining how this signaling axis becomes dysregulated in malignancies.

Extracellular vesicles rich in HAX1 promote angiogenesis by modulating ITGB6 translation

Tumour-associated angiogenesis plays a critical role in metastasis, the main cause of malignancy-related death. Extracellular vesicles (EVs) can regulate angiogenesis to participate in tumour metastasis. Our previous study showed that EVs rich in HAX1 are associated with in metastasis of nasopharyngeal carcinoma (NPC). However, the mechanism by which HAX1 of EVs promotes metastasis and angiogenesis is unclear. In this study, we demonstrated that EVs rich in HAX1 promote angiogenesis phenotype by activating the FAK pathway in endothelial cells (ECs) by increasing expression level of ITGB6. The expression level of HAX1 is markedly correlated with microvessel density (MVDs) in NPC and head and neck cancers based on an analysis of IHC. In addition to a series of in vitro cellular analyses, in vivo models revealed that HAX1 was correlated with migration and blood vessel formation of ECs, and metastasis of NPC. Using ribosome profiling, we found that HAX1 regulates the FAK pathway to influence microvessel formation and promote NPC metastasis by enhancing the translation efficiency of ITGB6. Our findings demonstrate that HAX1 can be used as an important biomarker for NPC metastasis, providing a novel basis for antiangiogenesis therapy in clinical settings.

Neutrophil Homeostasis and Emergency Granulopoiesis: The Example of Systemic Juvenile Idiopathic Arthritis

Neutrophils are key pathogen exterminators of the innate immune system endowed with oxidative and non-oxidative defense mechanisms. More recently, a more complex role for neutrophils as decision shaping cells that instruct other leukocytes to fine-tune innate and adaptive immune responses has come into view. Under homeostatic conditions, neutrophils are short-lived cells that are continuously released from the bone marrow. Their development starts with undifferentiated hematopoietic stem cells that pass through different immature subtypes to eventually become fully equipped, mature neutrophils capable of launching fast and robust immune responses. During severe (systemic) inflammation, there is an increased need for neutrophils. The hematopoietic system rapidly adapts to this increased demand by switching from steady-state blood cell production to emergency granulopoiesis. During emergency granulopoiesis, the de novo production of neutrophils by the bone marrow and at extramedullary sites is augmented, while additional mature neutrophils are rapidly released from the marginated pools. Although neutrophils are indispensable for host protection against microorganisms, excessive activation causes tissue damage in neutrophil-rich diseases. Therefore, tight regulation of neutrophil homeostasis is imperative. In this review, we discuss the kinetics of neutrophil ontogenesis in homeostatic conditions and during emergency myelopoiesis and provide an overview of the different molecular players involved in this regulation. We substantiate this review with the example of an autoinflammatory disease, i.e. systemic juvenile idiopathic arthritis.

CD147 deficiency is associated with impairedsperm motility/acrosome reaction and offersa therapeutic target for asthenozoospermia

Patients with asthenozoospermia often present multiple defects in sperm functions apart from a decrease in sperm motility. However, the etiological factors underlying these multifaceted defects remain mostly unexplored, which may lead to unnecessary treatment and unsatisfactory assisted reproductive technologies (ART) outcome. Here, we show that the protein levels of CD147 were lowered in sperm obtained from asthenozoospermic infertile patients exhibiting defects in both sperm motility and the acrosome reaction. Whereas CD147 maintained sperm motility before capacitation, female tract-derived soluble CD147 interacted with sperm-bound CD147 to induce an acrosome reaction in capacitated sperm. Soluble CD147 treatment restored the acrosome reaction and improved the fertility of sperm from patients with asthenozoospermia. Mechanistically, CD147 promotes sperm motility and acrosome reaction (AR) by eliciting Ca²⁺ influx through soluble CD147 binding to sperm-bound CD147. Notably, the level of soluble CD147 in seminal plasma was positively correlated with the fertilization rate and pregnancy outcome in infertile couples undergoing in vitro fertilization. Our study has identified a marker for the diagnosis and a therapeutic target for the defective AR capability in asthenozoospermia and a candidate for the prediction of in vitro fertilization outcomes for male infertile patients that facilitates the development of precision medicine in ART.

Kostmann disease and other forms of severe congenital neutropenia

Congenital neutropenia with autosomal recessive inheritance was first described by the Swedish paediatrician Rolf Kostmann who coined the term 'infantile genetic agranulocytosis'. The condition is now commonly referred to as Kostmann disease. These patients display a maturation arrest of the myelopoiesis in the bone marrow and reduced neutrophil numbers and suffer from recurrent, often life-threatening infections. The molecular mechanism underlying congenital neutropenia has been intensively investigated, and mutations in genes that impinge on programmed cell death have been identified. The present review provides an overview of these studies.

3D-STED Super-Resolution Microscopy Reveals Distinct Nanoscale Organization of the Hematopoietic Cell-Specific Lyn Substrate-1 (HS1) in Normal and Leukemic B Cells

HS1, the hematopoietic homolog of cortactin, acts as a versatile actin-binding protein in leucocytes. After phosphorylation, it is involved in GTPase and integrin activation, and in BCR, TCR, and CXCR4 downstream signaling. In normal and leukemic B cells, HS1 is a central cytoskeletal interactor and its phosphorylation and expression are prognostic factors in chronic lymphocytic leukemia (CLL) patients. We here introduce for the first time a super-resolution imaging study based on single-cell 3D-STED microscopy optimized for revealing and comparing the nanoscale distribution of endogenous HS1 in healthy B and CLL primary cells. Our study reveals that the endogenous HS1 forms heterogeneous nanoclusters, similar to those of YFP-HS1 overexpressed in the leukemic MEC1 cell line. HS1 nanoclusters in healthy and leukemic B cells form bulky assemblies at the basal sides, suggesting the recruitment of HS1 for cell adhesion. This observation agrees with a phasor-FLIM-FRET and STED colocalization analyses of the endogenous MEC1-HS1, indicating an increased interaction with Vimentin at the cell adhesion sites. In CLL cells isolated from patients with poor prognosis, we observed a larger accumulation of HS1 at the basal region and a higher density of HS1 nanoclusters in the central regions of the cells if compared to good-prognosis CLL and healthy B cells, suggesting a different role for the protein in the cell types analyzed. Our 3D-STED approach lays the ground for revealing tiny differences of HS1 distribution, its functionally active forms, and colocalization with protein partners.

A zebrafish model for HAX1-associated congenital neutropenia

Severe congenital neutropenia is a rare heterogeneous group of diseases, characterized by an arrest of granulocyte maturation. Autosomal recessive mutations in the HAX1 gene are frequently detected in affected individuals. However, the precise role of HAX1 during neutrophil differentiation is poorly understood. To date, no reliable animal model has been established to study HAX1-associated congenital neutropenia. Here we show that knockdown of zebrafish hax1 impairs neutrophil development without affecting other myeloid cells and erythrocytes. Furthermore, we found that interference with Hax1 function decreases the expression level of key target genes of the granulocyte colony-stimulating factor signaling pathway. The reduced neutrophil numbers in the morphants could be reversed by granulocyte colony-stimulating factor, which is also the main therapeutic intervention for patients who have congenital neutropenia. Our results demonstrate that the zebrafish is a suitable model for HAX1-associated neutropenia. We anticipate that this model will serve as an in vivo platform to identify new avenues for developing tailored therapeutic strategies for patients with congenital neutropenia, particularly for those individuals who do not respond to granulocyte colony-stimulating factor treatment.

Integrative transcriptomic analysis of developing hematopoietic stem cells in human and mouse at single-cell resolution

Current understanding of hematopoietic stem cell (HSC) development comes from mouse models is considered to be evolutionarily conserved in human. However, the cross-species comparison of the transcriptomic profiles of developmental HSCs at single-cell level is still lacking. Here, we performed integrative transcriptomic analysis of a series of key cell populations during HSC development in human and mouse, including HSC-primed hemogenic endothelial cells and pre-HSCs in mid-gestational aorta-gonad-mesonephros (AGM) region, and mature HSCs in fetal liver and adult bone marrow. We demonstrated the general similarity of transcriptomic characteristics between corresponding cell populations of the two species. Of note, one of the previously transcriptomically defined hematopoietic stem progenitor cell (HSPC) populations with certain arterial characteristics in AGM region of human embryos showed close transcriptomic similarity to pre-HSCs in mouse embryos. On the other hand, the other two HSPC populations in human AGM region displayed molecular similarity with fetal liver HSPCs, suggesting the maturation in AGM before HSCs colonizing the fetal liver in human, which was different to that in mouse. Finally, we re-clustered cells based on the integrated dataset and illustrated the evolutionarily conserved molecular signatures of major cell populations. Our results revealed transcriptomic conservation of critical cell populations and molecular characteristics during HSC development between human and mouse, providing a resource and theoretic basis for future studies on mammalian HSC development and regeneration by using mouse models.

The interactome of multifunctional HAX1 protein suggests its role in the regulation of energy metabolism, de-aggregation, cytoskeleton organization and RNA-processing

HCLS1-associated protein X-1 (HAX1) is a multifunctional protein involved in many cellular processes, including apoptosis, cell migration and calcium homeostasis, but its mode of action still remains obscure. Multiple HAX1 protein partners have been identified, but they are involved in many distinct pathways, form different complexes and do not constitute a coherent group. By characterizing HAX1 protein interactome using targeted approach, we attempt to explain HAX1 multiple functions and its role in the cell. Presented analyses indicate that HAX1 interacts weakly with a wide spectrum of proteins and its interactome tends to be cell-specific, which conforms to a profile of intrinsically disordered protein (IDP). Moreover, we have identified a mitochondrial subset of HAX1 protein partners and preliminarily characterized its involvement in the cellular response to oxidative stress and aggregation.

Analysis for interaction between interleukin-35 genes polymorphisms and risk factors on susceptibility to coronary heart disease in the Chinese Han population

BACKGROUND

The relationship between IL-35 genes polymorphism and susceptibility to coronary heart disease has not been tested in the largest Han population in China. The aim of this study was to explore the effect of single nucleotide polymorphisms (SNPs) of interleukin-35 (IL-35) genes and its relationship with environment on the risk of coronary heart disease (CHD).

METHODS

We performed Hardy-Weinberg equilibrium test on the control group. The relationship between the four SNPs of IL-35 genes and the risk of coronary heart disease was studied by multivariate logistic regression. The best interaction was identified with generalized multifactor dimensionality reduction (GMDR). Logistic regression was used for investigation on association between four SNPs and CHD risk.

RESULTS

Logistic regression analysis showed that the C allele of rs428253 and the G allele of rs2243115 were independently correlated with increased risk of CHD, and adjusted ORs (95% CI) were 1.91 (1.28-2.64) and 1.80 (1.30-2.23), respectively. However, there was no significant association between CHD and rs4740 or rs568408. GMDR model indicated a best model for CHD risk consisted of rs428253 and current smoking, which scored 10/10 for both the sign test and cross-validation consistency (p = 0.010). Therefore, this overall multi-dimensional model had the highest cross-validation consistency, regardless of how the data were divided. This provided an evidence of gene-environment interaction effects. We also found that current smokers with rs428253-GC/CC genotype have the highest CHD risk, compared to never smokers with rs428253-GG genotype, OR (95% CI) = 3.04 (1.71-4.41), after adjustment for age, gender, hypertension, T2DM and alcohol consumption status.

CONCLUSIONS

In this study, the C allele of rs428253 and the G allele of rs2243115, and the interaction rs428253 and current smoking were correlated with increased risk of CHD.

Neutrophil diversity and plasticity in tumour progression and therapy

Neutrophils play a key role in defence against infection and in the activation and regulation of innate and adaptive immunity. In cancer, tumour-associated neutrophils (TANs) have emerged as an important component of the tumour microenvironment. Here, they can exert dual functions. TANs can be part of tumour-promoting inflammation by driving angiogenesis, extracellular matrix remodelling, metastasis and immunosuppression. Conversely, neutrophils can also mediate antitumour responses by direct killing of tumour cells and by participating in cellular networks that mediate antitumour resistance. Neutrophil diversity and plasticity underlie the dual potential of TANs in the tumour microenvironment. Myeloid checkpoints as well as the tumour and tissue contexture shape neutrophil function in response to conventional therapies and immunotherapy. We surmise that neutrophils can provide tools to tailor current immunotherapy strategies and pave the way to myeloid cell-centred therapeutic strategies, which would be complementary to current approaches.

Understanding HCMV Latency Using Unbiased Proteomic Analyses

Human cytomegalovirus (HCMV) establishes either a latent (non-productive) or lytic (productive) infection depending upon cell type, cytokine milieu and the differentiation status of the infected cell. Undifferentiated cells, such as precursor cells of the myeloid lineage, support a latent infection whereas terminally differentiated cells, such as monocytes or dendritic cells are an environment conducive to reactivation and support a lytic infection. The mechanisms which regulate HCMV in either a latent or lytic infection have been the focus of intense investigation with a view to developing novel treatments for HCMV-associated disease which can have a heavy clinical burden after reactivation or primary infection in, especially, the immune compromised. To this end, a number of studies have been carried out in an unbiased manner to address global changes occurring within the latently infected cell to address the molecular changes associated with HCMV latency. In this review, we will concentrate on the proteomic analyses which have been carried out in undifferentiated myeloid cells which either stably express specific viral latency associated genes in isolation or on cells which have been latently infected with virus.

Primary Immunodeficiencies With Defects in Innate Immunity: Focus on Orofacial Manifestations

The field of primary immunodeficiencies (PIDs) is rapidly evolving. Indeed, the number of described diseases is constantly increasing thanks to the rapid identification of novel genetic defects by next-generation sequencing. PIDs are now rather referred to as “inborn errors of immunity” due to the association between a wide range of immune dysregulation-related clinical features and the “prototypic” increased infection susceptibility. The phenotypic spectrum of PIDs is therefore very large and includes several orofacial features. However, the latter are often overshadowed by severe systemic manifestations and remain underdiagnosed. Patients with impaired innate immunity are predisposed to a variety of oral manifestations including oral infections (e.g., candidiasis, herpes gingivostomatitis), aphthous ulcers, and severe periodontal diseases. Although less frequently, they can also show orofacial developmental abnormalities. Oral lesions can even represent the main clinical manifestation of some PIDs or be inaugural, being therefore one of the first features indicating the existence of an underlying immune defect. The aim of this review is to describe the orofacial features associated with the different PIDs of innate immunity based on the new 2019 classification from the International Union of Immunological Societies (IUIS) expert committee. This review highlights the important role played by the dentist, in close collaboration with the multidisciplinary medical team, in the management and the diagnostic of these conditions.

Integrated miRNA-mRNA network revealing the key molecular characteristics of ossification of the posterior longitudinal ligament

BACKGROUND

Ossification of the posterior longitudinal ligament (OPLL) refers to an ectopic ossification disease originating from the posterior longitudinal ligament of the spine. Pressing on the spinal cord or nerve roots can cause limb sensory and motor disorders, significantly reducing the patient's quality of life. At present, the pathogenesis of OPLL is still unclear. The purpose of this study is to integrate microRNA (miRNA)-mRNA biological information data to further analyze the important molecules in the pathogenesis of OPLL, so as to provide targets for future OPLL molecular therapy.

METHODS

miRNA and mRNA expression profiles of GSE69787 were downloaded from Gene Expression Omnibus database and analyzed by edge R package. Funrich software was used to predict the target genes and transcription factors of de-miRNA. Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis of differentially expressed genes (DEGs) were carried out based on CLUEGO plug-in in Cytoscape. Using data collected from a search tool for the retrieval of interacting genes online database, a protein-protein interaction (PPI) network was constructed using Cytoscape. The hub gene selection and module analysis of PPI network were carried out by cytoHubba and molecular complex detection, plug-ins of Cytoscape software respectively.

RESULTS

A total of 346 genes, including 247 up-regulated genes and 99 down-regulated genes were selected as DEGs. SP1 was identified as an upstream transcription factor of de-miRNAs. Notably, gene ontology enrichment analysis shows that up- and down-regulated DEGs are mainly involved in BP, such as skeletal structure morphogenesis, skeletal system development, and animal organ morphogenesis. Kyoto Encyclopedia of Genes and Genomes enrichment analysis indicated that only WNT signaling pathway was associated with osteogenic differentiation. Lymphoid enhancer binding factor 1 and wingless-type MMTV integration site family member 2 Wingless-Type MMTV Integration site family member 2 were identified as hub genes, miR-520d-3p, miR-4782-3p, miR-6766-3p, and miR-199b-5p were identified as key miRNAs. In addition, 2 important network modules were obtained from PPI network.

CONCLUSIONS

In this study, we established a potential miRNA-mRNA regulatory network associated with OPLL, revealing the key molecular mechanism of OPLL and providing targets for future treatment or prevent its occurrence.

C/EBPβ is a critical mediator of IFN-α-induced exhaustion of chronic myeloid leukemia stem cells

Even in the era of ABL tyrosine kinase inhibitors, eradication of chronic myeloid leukemia (CML) stem cells is necessary for complete cure of the disease. Interferon-α (IFN-α) has long been used for the treatment of chronic-phase CML, but its mechanisms of action against CML stem cells remain unclear. We found that IFN-α upregulated CCAAT/enhancer binding protein β (C/EBPβ) in BCR-ABL-expressing mouse cells by activating STAT1 and STAT5, which were recruited to a newly identified 3' distal enhancer of Cebpb that contains tandemly aligned IFN-γ-activated site elements. Suppression or deletion of the IFN-γ-activated site elements abrogated IFN-α-dependent upregulation of C/EBPβ. IFN-α induced differentiation and exhaustion of CML stem cells, both in vitro and in vivo, in a C/EBPβ-dependent manner. In addition, IFN-α upregulated C/EBPβ and induced exhaustion of lineage^- CD34⁺ cells from CML patients. Collectively, these results clearly indicate that C/EBPβ is a critical mediator of IFN-α-induced differentiation and exhaustion of CML stem cells.

Natural Autoantibodies in Chronic Pulmonary Diseases

In autoantibody-mediated autoimmune diseases, pathogenic autoantibodies generated by a failure of central or peripheral tolerance, have different effects mediated by a variety of mechanisms. Interestingly, even non-autoimmune chronic diseases have a set of disease-specific natural autoantibodies that are maintained for a long time. Because most of these natural autoantibodies target intracellular proteins or long non-coding RNAs, they are speculated to be non-pathological and have some important as yet unrecognized physiological functions such as debris clearance. Recently, we revealed a set of disease-specific natural autoantibodies of chronic pulmonary diseases with unknown etiology by protein arrays that enable detection of specific autoantibodies against >8000 targets. Surprisingly, some of the targeted antigens of disease-specific autoantibodies were subsequently reported by other laboratories as strongly associated with the disease, suggesting that these antigens reflect the pathology of each disease. Furthermore, some of these autoantibodies that target extracellular antigens might modify the original course of each disease. Here, we review the disease-specific natural autoantibodies of chronic pulmonary diseases, including chronic fibrosing idiopathic interstitial pneumonias, sarcoidosis, and autoimmune pulmonary alveolar proteinosis, and discuss their utility and effects.

Lymphatic Endothelial Cell Progenitors in the Tumor Microenvironment

Tumor lymphatics play a key role in cancer progression as they are solely responsible for transporting malignant cells to regional lymph nodes (LNs), a process that precedes and promotes systemic lethal spread. It is broadly accepted that tumor lymphatic sprouting is induced mainly by soluble factors derived from tumor-associated macrophages (TAMs) and malignant cells. However, emerging evidence strongly suggests that a subset of TAMs, myeloid-lymphatic endothelial cell progenitors (M-LECP), also contribute to the expansion of lymphatics through both secretion of paracrine factors and a self-autonomous mode. M-LECP are derived from bone marrow (BM) precursors of the monocyte-macrophage lineage and characterized by unique co-expression of markers identifying lymphatic endothelial cells (LEC), stem cells, M2-type macrophages, and myeloid-derived immunosuppressive cells. This review describes current evidence for the origin of M-LECP in the bone marrow, their recruitment tumors and intratumoral trafficking, similarities to other TAM subsets, and mechanisms promoting tumor lymphatics. We also describe M-LECP integration into preexisting lymphatic vessels and discuss potential mechanisms and significance of this event. We conclude that improved mechanistic understanding of M-LECP functions within the tumor environment may lead to new therapeutic approaches to suppress tumor lymphangiogenesis and metastasis to lymph nodes.

Primary immunodeficiencies reveal the essential role of tissue neutrophils in periodontitis

Periodontitis is a common human inflammatory disease. In this condition, microbiota trigger excessive inflammation in oral mucosal tissues surrounding the dentition, resulting in destruction of tooth-supporting structures (connective tissue and bone). While susceptibility factors for common forms of periodontitis are not clearly understood, studies in patients with single genetic defects reveal a critical role for tissue neutrophils in disease susceptibility. Indeed, various genetic defects in the development, egress from the bone marrow, chemotaxis, and extravasation are clearly linked to aggressive/severe periodontitis at an early age. Here, we provide an overview of genetic defects in neutrophil biology that are linked to periodontitis. In particular, we focus on the mechanisms underlying Leukocyte Adhesion Deficiency-I, the prototypic Mendelian defect of impaired neutrophil extravasation and severe periodontitis.

Myeloid-Derived Lymphatic Endothelial Cell Progenitors Significantly Contribute to Lymphatic Metastasis in Clinical Breast Cancer

Lymphatic metastasis is a high-impact prognostic factor for mortality of breast cancer (BC) patients, and it directly depends on tumor-associated lymphatic vessels. We previously reported that lipopolysaccharide-induced inflammatory lymphangiogenesis is strongly promoted by myeloid-derived lymphatic endothelial cell progenitors (M-LECPs) derived from the bone marrow (BM). As BC recruits massive numbers of provascular myeloid cells, we hypothesized that M-LECPs, within this recruited population, are specifically programmed to promote tumor lymphatics that increase lymph node metastasis. In support of this hypothesis, high levels of M-LECPs were found in peripheral blood and tumor tissues of BC patients. Moreover, the density of M-LECPs and lymphatic vessels positive for myeloid marker proteins strongly correlated with patient node status. It was also established that tumor M-LECPs coexpress lymphatic-specific, stem/progenitor and M2-type macrophage markers that indicate their BM hematopoietic-myeloid origin and distinguish them from mature lymphatic endothelial cells, tumor-infiltrating lymphoid cells, and tissue-resident macrophages. Using four orthotopic BC models, we show that mouse M-LECPs are similarly recruited to tumors and integrate into preexisting lymphatics. Finally, we demonstrate that adoptive transfer of in vitro differentiated M-LECPs, but not naïve or nondifferentiated BM cells, significantly increased metastatic burden in ipsilateral lymph nodes. These data support a causative role of BC-induced lymphatic progenitors in tumor lymphangiogenesis and suggest molecular targets for their inhibition.

Association between interleukin-35 polymorphisms and coronary heart disease in the Chinese Zhuang population: a case-control study

OBJECTIVES

Inflammatory cytokines play an important role in the pathogenesis of cardiovascular disease. Few studies have investigated the association between interleukin-35 (IL-35) genetic variants and the risk of coronary heart disease (CHD). We examined the association between IL-35 polymorphisms and CHD in the Chinese Zhuang population.

PATIENTS AND METHODS

A total of 707 CHD patients and 707 age-matched and sex-matched controls were enrolled in this case-control study. Genotypes of the single nucleotide polymorphisms (SNPs) of IL-35, including rs428253, rs6613, rs9807813, rs2243115, rs568408, rs582054, rs583911, rs4740, and rs393581, were examined by MassArray. Plasma IL-35 level was measured using an enzyme-linked immunosorbent assay. The multivariate logistic regression model was used to evaluate the association between the SNPs and the risk of CHD.

RESULTS

In the Chinese Zhuang population, compared with the GG genotype of EBI3 rs428253, individuals with the CC genotype had a 2.02-fold (95% confidence interval: 1.07-3.84, P=0.031) higher risk of CHD. Further adjustment for potential risk factors did not alter the positive association (CC vs. GG, odds ratio=2.30, 95% confidence interval: 1.16-4.54, P=0.042). SNPs rs4740, rs2243115, rs568408, and rs582054 were not statistically related to the risk of CHD. The plasma IL-35 levels showed a marginally significant difference between rs428253 genotypes [GG: 13.39 (7.89-19.25) vs. CC+GC: 17.53 (8.98-22.56) pg/ml, P=0.057].

CONCLUSION

The EBI3 rs428253 CC genotype was associated with an increased risk of CHD in the Chinese Zhuang population, although no significant difference in IL-35 levels was observed between genotypes in healthy controls.

CRISPR/Cas9-mediated ELANE knockout enables neutrophilic maturation of primary hematopoietic stem and progenitor cells and induced pluripotent stem cells of severe congenital neutropenia patients

A Autosomal-dominant ELANE mutations are the most common cause of severe congenital neutropenia. Although the majority of congenital neutropenia patients respond to daily granulocyte colony stimulating factor, approximately 15 % do not respond to this cytokine at doses up to 50 μg/kg/day and approximately 15 % of patients will develop myelodysplasia or acute myeloid leukemia. “Maturation arrest,” the failure of the marrow myeloid progenitors to form mature neutrophils, is a consistent feature of ELANE associated congenital neutropenia. As mutant neutrophil elastase is the cause of this abnormality, we hypothesized that ELANE associated neutropenia could be treated and “maturation arrest” corrected by a CRISPR/Cas9-sgRNA ribonucleoprotein mediated ELANE knockout. To examine this hypothesis, we used induced pluripotent stem cells from two congenital neutropenia patients and primary hematopoietic stem and progenitor cells from four congenital neutropenia patients harboring ELANE mutations as well as HL60 cells expressing mutant ELANE. We observed that granulocytic differentiation of ELANE knockout induced pluripotent stem cells and primary hematopoietic stem and progenitor cells were comparable to healthy individuals. Phagocytic functions, ROS production, and chemotaxis of the ELANE KO (knockout) neutrophils were also normal. Knockdown of ELANE in the mutant ELANE expressing HL60 cells also allowed full maturation and formation of abundant neutrophils. These observations suggest that ex vivo CRISPR/Cas9 RNP based ELANE knockout of patients’ primary hematopoietic stem and progenitor cells followed by autologous transplantation may be an alternative therapy for congenital neutropenia.

Hematopoietic cell-specific lyn substrate (HCLS1 or HS1): A versatile actin-binding protein in leukocytes

Leukocytes are constantly produced in the bone marrow and released into the circulation. Many different leukocyte subpopulations exist that exert distinct functions. Leukocytes are recruited to sites of inflammation and combat the cause of inflammation via many different effector functions. Virtually all of these processes depend on dynamic actin remodeling allowing leukocytes to adhere, migrate, phagocytose, and release granules. However, actin dynamics are not possible without actin-binding proteins (ABP) that orchestrate the balance between actin polymerization, branching, and depolymerization. The homologue of the ubiquitous ABP cortactin in hematopoietic cells is hematopoietic cell-specific lyn substrate-1, often called hematopoietic cell-specific protein-1 (HCLS1 or HS1). HS1 has been reported in different leukocytes to regulate Arp2/3-dependent migration. However, more evidence is emerging that HS1 functions go far beyond just being a direct actin modulator. For example, HS1 is important for the activation of GTPases and integrins, and mediates signaling downstream of many receptors including BCR, TCR, and CXCR4. In this review, we summarize current knowledge on HS1 functions and discuss them in a pathophysiologic context.

Identification of the Functional Autophagy-Regulatory Domain in HCLS1-Associated Protein X-1 That Resists Against Oxidative Stress

HCLS1 Associated Protein X-1 (HAX1) promotes cell survival through attenuation of the damaged signals from endoplasmic reticulum and mitochondria, which are known as prominent intracellular compartments for the autophagic process under stress conditions. This study investigates whether autophagy can be upregulated in response to HAX1 overexpression and identifies the functional motif in HAX1 responsible for the autophagic induction. Autophagosome accumulation, mitochondrial membrane potential (Δψm), and apoptosis were assessed in HEK293 cells post transduction with full-length or truncated HAX1-encoding genes, while empty vector-transduced cells served as control. Upon the oxidative stress, the enhanced autophagy induction was observed in cells overexpressing HAX1, as well as HAX1 truncations that encode peptide segments ranging from amino acids 127-180 (AA127-180). This protective response was further supported by flow cytometry and Western Blot results, in which oxidative stress-induced Δψm dissipation and the programmed cell death were suppressed in HAX1-overexpressing cells, associated with reduced DNA fragmentation and decreased Caspase-9 cleavage. Interestingly, the HAX1-induced autophagy response was abrogated when AA127-180 was removed, compromising the antiapoptotic effects upon oxidative stress. Overall, these data indicate that autophagy induction is involved in HAX1-induced cell protective mechanism, and AA127-180 serves as the functional autophagy-regulatory domain of this antiapoptotic protein.

NRL-Regulated Transcriptome Dynamics of Developing Rod Photoreceptors

Gene regulatory networks (GRNs) guiding differentiation of cell types and cell assemblies in the nervous system are poorly understood because of inherent complexities and interdependence of signaling pathways. Here, we report transcriptome dynamics of differentiating rod photoreceptors in the mammalian retina. Given that the transcription factor NRL determines rod cell fate, we performed expression profiling of developing NRL-positive (rods) and NRL-negative (S-cone-like) mouse photoreceptors. We identified a large-scale, sharp transition in the transcriptome landscape between postnatal days 6 and 10 concordant with rod morphogenesis. Rod-specific temporal DNA methylation corroborated gene expression patterns. De novo assembly and alternative splicing analyses revealed previously unannotated rod-enriched transcripts and the role of NRL in transcript maturation. Furthermore, we defined the relationship of NRL with other transcriptional regulators and downstream cognate effectors. Our studies provide the framework for comprehensive system-level analysis of the GRN underlying the development of a single sensory neuron, the rod photoreceptor.

CCR6 is required for ligand-induced CatSper activation in human sperm

CatSper channel has been considered the principal sperm Ca²⁺ channel responsible for the cytosolic Ca²⁺ elevation required for various sperm functions necessary for fertilization [1–4]. However, the mechanism underlying the activation of CatSper channel by various physiological ligands remain incompletely understood. We have recently demonstrated the expression of C-C chemokine receptor 6 (CCR6) in sperm and Ca²⁺ influx upon binding of human β-defensin 1 (DEFB1) to CCR6, which is important for sperm motility [5]. In the present study, we have demonstrated that CCR6 receptor and CatSper channel are both required for the Ca²⁺ entry/current induced by physiological ligands DEFB1, chemokine (C-C motif) ligand 20 (CCL20) and progesterone in human sperm. CCR6 is co-localized and interacts with CatSper in human sperm. Ca²⁺ influx mediated by CCR6 and CatSper is required for essential sperm functions, including motility, hyperactivation and acrosome reaction, which are impaired in infertile sperm showing reduced levels of CCR6 and CatSper. The present finding suggests a critical role of CCR6 receptor in mediating ligand-induced, CatSper-dependent Ca²⁺ influx required for various sperm functions and thus male fertility.

Role of CSF3R mutations in the pathomechanism of congenital neutropenia and secondary acute myeloid leukemia

Acquired mutations in the intracellular part of CSF3R (colony stimulating factor 3 receptor, granulocyte) have been detected with a frequency of more than 30% in severe congenital neutropenia (CN) patients. CN is a preleukemic syndrome with a risk of approximately 20% to develop leukemia. More than 80% of CN patients who develop acute myeloid leukemia or myelodysplastic syndrome reveal CSF3R mutations, suggesting that they are involved in leukemogenesis. Using deep-sequencing technology, we were able to analyze large cohorts of CN patients for the entire CSF3R sequence as well as to identify cell clones carrying mutations in the intracellular part of CSF3R with very high sensitivity. Acquisition of CSF3R mutations is a CN-specific phenomenon and is associated with inherited mutations causing CN or cyclic neutropenia, such as ELANE mutations. In the group of CN patients negative for known germ-line mutations, biallelic CSF3R mutations were identified. In addition, CSF3R mutant clones are highly dynamic and may disappear and reappear during continuous granulocyte colony-stimulating factor (G-CSF) therapy. The time between the first detection of CSF3R mutations and overt leukemia is highly variable.

Severe congenital neutropenias

Severe congenital neutropenias are a heterogeneous group of rare haematological diseases characterized by impaired maturation of neutrophil granulocytes. Patients with severe congenital neutropenia are prone to recurrent, often life-threatening infections beginning in their first months of life. The most frequent pathogenic defects are autosomal dominant mutations in ELANE, which encodes neutrophil elastase, and autosomal recessive mutations in HAX1, whose product contributes to the activation of the granulocyte colony-stimulating factor (G-CSF) signalling pathway. The pathophysiological mechanisms of these conditions are the object of extensive research and are not fully understood. Furthermore, severe congenital neutropenias may predispose to myelodysplastic syndromes or acute myeloid leukaemia. Molecular events in the malignant progression include acquired mutations in CSF3R (encoding G-CSF receptor) and subsequently in other leukaemia-associated genes (such as RUNX1) in a majority of patients. Diagnosis is based on clinical manifestations, blood neutrophil count, bone marrow examination and genetic and immunological analyses. Daily subcutaneous G-CSF administration is the treatment of choice and leads to a substantial increase in blood neutrophil count, reduction of infections and drastic improvement of quality of life. Haematopoietic stem cell transplantation is the alternative treatment. Regular clinical assessments (including yearly bone marrow examinations) to monitor treatment course and detect chromosomal abnormalities (for example, monosomy 7 and trisomy 21) as well as somatic pre-leukaemic mutations are recommended.

Gene correction of HAX1 reversed Kostmann disease phenotype in patient-specific induced pluripotent stem cells

Severe congenital neutropenia (SCN, Kostmann disease) is a heritable disorder characterized by a granulocytic maturation arrest. Biallelic mutations in HCLS1 associated protein X-1 (HAX1) are frequently detected in affected individuals, including those of the original pedigree described by Kostmann in 1956. To date, no faithful animal model has been established to study SCN mediated by HAX1 deficiency. Here we demonstrate defective neutrophilic differentiation and compensatory monocyte overproduction from patient-derived induced pluripotent stem cells (iPSCs) carrying the homozygous HAX1^W44X nonsense mutation. Targeted correction of the HAX1 mutation using the CRISPR-Cas9 system and homologous recombination rescued neutrophil differentiation and reestablished an HAX1 and HCLS1-centered transcription network in immature myeloid progenitors, which is involved in the regulation of apoptosis, apoptotic mitochondrial changes, and myeloid differentiation. These findings made in isogenic iPSC-derived myeloid cells highlight the complex transcriptional changes underlying Kostmann disease. Thus, we show that patient-derived HAX1^W44X -iPSCs recapitulate the Kostmann disease phenotype in vitro and confirm HAX1 mutations as the disease-causing monogenic lesion. Finally, our study paves the way for nonvirus-based gene therapy approaches in SCN.

Wnt5a induces ROR1 to complex with HS1 to enhance migration of chronic lymphocytic leukemia cells

ROR1 (receptor tyrosine kinase-like orphan receptor 1) is a conserved, oncoembryonic surface antigen expressed in chronic lymphocytic leukemia (CLL). We found that ROR1 associates with hematopoietic-lineage-cell-specific protein 1 (HS1) in freshly isolated CLL cells or in CLL cells cultured with exogenous Wnt5a. Wnt5a also induced HS1 tyrosine phosphorylation, recruitment of ARHGEF1, activation of RhoA and enhanced chemokine-directed migration; such effects could be inhibited by cirmtuzumab, a humanized anti-ROR1 mAb. We generated truncated forms of ROR1 and found its extracellular cysteine-rich domain or kringle domain was necessary for Wnt5a-induced HS1 phosphorylation. Moreover, the cytoplamic, and more specifically the proline-rich domain (PRD), of ROR1 was required for it to associate with HS1 and allow for F-actin polymerization in response to Wnt5a. Accordingly, we introduced single amino acid substitutions of proline (P) to alanine (A) in the ROR1 PRD at positions 784, 808, 826, 841 or 850 in potential SH3-binding motifs. In contrast to wild-type ROR1, or other ROR1^P→A mutants, ROR1^P(841)A had impaired capacity to recruit HS1 and ARHGEF1 to ROR1 in response to Wnt5a. Moreover, Wnt5a could not induce cells expressing ROR1^P(841)A to phosphorylate HS1 or activate ARHGEF1, and was unable to enhance CLL-cell motility. Collectively, these studies indicate HS1 plays an important role in ROR1-dependent Wnt5a-enhanced chemokine-directed leukemia-cell migration.

Interleukin 35 Polymorphisms Are Associated with Decreased Risk of Premature Coronary Artery Disease, Metabolic Parameters, and IL-35 Levels: The Genetics of Atherosclerotic Disease (GEA) Study

Interleukin 35 (IL-35) is a heterodimeric cytokine involved in the development of atherosclerosis. The aim of the present study was to establish if the polymorphisms of IL-12A and EBI3 genes that encode the IL-35 subunits are associated with the development of premature coronary artery disease (CAD) in Mexican individuals. The IL-12A and EBI3 polymorphisms were determined in 1162 patients with premature CAD and 873 controls. Under different models, the EBI3 rs428253 (OR = 0.831, P_add = 0.036; OR = 0.614, P_rec = 0.033; OR = 0.591, P_cod2 = 0.027) and IL-12A rs2243115 (OR = 0.674, P_add = 0.010; OR = 0.676, P_dom = 0.014; OR = 0.698, P_het = 0.027; OR = 0.694, P_cod1 = 0.024) polymorphisms were associated with decreased risk of developing premature CAD. Some polymorphisms were associated with clinical and metabolic parameters. Significant different levels of IL-35 were observed in EBI3 rs4740 and rs4905 genotypes only in the group of healthy controls. In summary, our study suggests that the EBI3 and IL-12A polymorphisms play an important role in decreasing the risk of developing premature CAD; it also demonstrates the relationship of the EBI3 rs4740 and rs4905 genotypes with IL-35 levels in healthy individuals.

HAX1 mutation positive children presenting with haemophagocytic lymphohistiocytosis

The genetic basis of haemophagocytic lymphohistiocytosis (HLH) has not been elucidated in 10% of affected patients. In this study, we report four HLH episodes in three patients with HAX1 gene mutations. We screened the mutations associated with congenital neutropenia (CN) because the neutropenia persisted following HLH treatment. There were homozygous HAX1 mutations detected in all patients. This is the first case series of patients with CN caused by HAX1 mutation who presented with HLH. We hypothesize that severe neutropenia persists after an HLH episode in children without HLH mutations (especially infants) because these patients have CN caused by HAX1 mutations.

Children with rare diseases of neutrophil granulocytes: from therapeutic orphans to pioneers of individualized medicine

Neutrophil granulocytes are the most abundant immune cells in the blood yet the pathways orchestrating their differentiation and biological function remain incompletely understood. Studying (ultra-) rare patients with monogenetic defects of neutrophil granulocytes may open new horizons to understand basic principles of hematopoiesis and innate immunity. Here, recent insights into genetic factors controlling myelopoiesis and their more general role in biology will be presented in a clinical perspective. Advances in supportive care, first and foremost the use of recombinant human granulocyte-colony stimulating factor, has made a substantial difference for the quality of life and life expectancy of patients with congenital neutropenia (CN). Up to date, the only definitive cure can be provided by transplantation of allogeneic hematopoietic stem cells. The elucidation of the underlying molecular factors contributing to defective differentiation and function of neutrophil granulocytes nurtures new ideas of targeted individualized therapies.

Identification of RNA-binding Proteins in Macrophages by Interactome Capture

Pathogen components, such as lipopolysaccharides of Gram-negative bacteria that activate Toll-like receptor 4, induce mitogen activated protein kinases and NFκB through different downstream pathways to stimulate pro- and anti-inflammatory cytokine expression. Importantly, post-transcriptional control of the expression of Toll-like receptor 4 downstream signaling molecules contributes to the tight regulation of inflammatory cytokine synthesis in macrophages. Emerging evidence highlights the role of RNA-binding proteins (RBPs) in the post-transcriptional control of the innate immune response. To systematically identify macrophage RBPs and their response to LPS stimulation, we employed RNA interactome capture in LPS-induced and untreated murine RAW 264.7 macrophages. This combines RBP-crosslinking to RNA, cell lysis, oligo(dT) capture of polyadenylated RNAs and mass spectrometry analysis of associated proteins. Our data revealed 402 proteins of the macrophage RNA interactome including 91 previously not annotated as RBPs. A comparison with published RNA interactomes classified 32 RBPs uniquely identified in RAW 264.7 macrophages. Of these, 19 proteins are linked to biochemical activities not directly related to RNA. From this group, we validated the HSP90 cochaperone P23 that was demonstrated to exhibit cytosolic prostaglandin E2 synthase 3 (PTGES3) activity, and the hematopoietic cell-specific LYN substrate 1 (HCLS1 or HS1), a hematopoietic cell-specific adapter molecule, as novel macrophage RBPs. Our study expands the mammalian RBP repertoire, and identifies macrophage RBPs that respond to LPS. These RBPs are prime candidates for the post-transcriptional regulation and execution of LPS-induced signaling pathways and the innate immune response. Macrophage RBP data have been deposited to ProteomeXchange with identifier PXD002890.

Practice parameter for the diagnosis and management of primary immunodeficiency

The American Academy of Allergy, Asthma & Immunology (AAAAI) and the American College of Allergy, Asthma & Immunology (ACAAI) have jointly accepted responsibility for establishing the "Practice parameter for the diagnosis and management of primary immunodeficiency." This is a complete and comprehensive document at the current time. The medical environment is a changing environment, and not all recommendations will be appropriate for all patients. Because this document incorporated the efforts of many participants, no single individual, including those who served on the Joint Task Force, is authorized to provide an official AAAAI or ACAAI interpretation of these practice parameters. Any request for information about or an interpretation of these practice parameters by the AAAAI or ACAAI should be directed to the Executive Offices of the AAAAI, the ACAAI, and the Joint Council of Allergy, Asthma & Immunology. These parameters are not designed for use by pharmaceutical companies in drug promotion.

Pathogenesis of ELANE-mutant severe neutropenia revealed by induced pluripotent stem cells

Severe congenital neutropenia (SCN) is often associated with inherited heterozygous point mutations in ELANE, which encodes neutrophil elastase (NE). However, a lack of appropriate models to recapitulate SCN has substantially hampered the understanding of the genetic etiology and pathobiology of this disease. To this end, we generated both normal and SCN patient-derived induced pluripotent stem cells (iPSCs), and performed genome editing and differentiation protocols that recapitulate the major features of granulopoiesis. Pathogenesis of ELANE point mutations was the result of promyelocyte death and differentiation arrest, and was associated with NE mislocalization and activation of the unfolded protein response/ER stress (UPR/ER stress). Similarly, high-dose G-CSF (or downstream signaling through AKT/BCL2) rescues the dysgranulopoietic defect in SCN patient-derived iPSCs through C/EBPβ-dependent emergency granulopoiesis. In contrast, sivelestat, an NE-specific small-molecule inhibitor, corrected dysgranulopoiesis by restoring normal intracellular NE localization in primary granules; ameliorating UPR/ER stress; increasing expression of CEBPA, but not CEBPB; and promoting promyelocyte survival and differentiation. Together, these data suggest that SCN disease pathogenesis includes NE mislocalization, which in turn triggers dysfunctional survival signaling and UPR/ER stress. This paradigm has the potential to be clinically exploited to achieve therapeutic responses using lower doses of G-CSF combined with targeting to correct NE mislocalization.

Non-steady-state hematopoiesis regulated by the C/EBPβ transcription factor

Steady-state hematopoiesis responds to extracellular stimuli to meet changing demands and also to pathologically altered intracellular signaling. Granulocyte production increases following infection or in response to cytokine stimulation, and activation of the CCAAT/enhancer-binding protein β (C/EBPβ) transcription factor is required for such stress-induced granulopoiesis, whereas C/EBPα plays a critical role in maintaining steady-state granulopoiesis. Different roles of these C/EBP transcription factors in different modes of hematopoiesis are evolutionally conserved from zebrafish to humans. In addition to reactions against infections, C/EBPβ is responsible for cancer-driven myelopoiesis, which promotes cancer progression, at least in part, by abrogating the immune response in the cancer microenvironment. The BCR–ABL fusion protein activates emergency-specific pathway of granulopoiesis by upregulating C/EBPβ. This in turn causes chronic phase chronic myeloid leukemia, which is characterized by myeloid expansion. The C/EBPβ transcription factor also plays a role in other hematological malignancies of both myeloid and lymphoid lineage origin. Thus, elucidation of the upstream and downstream networks surrounding C/EBPβ will lead to the development of novel therapeutic strategies for diseases mediated by non-steady-state hematopoiesis.

Neutrophils: Between host defence, immune modulation, and tissue injury

Neutrophils, the most abundant human immune cells, are rapidly recruited to sites of infection, where they fulfill their life-saving antimicrobial functions. While traditionally regarded as short-lived phagocytes, recent findings on long-term survival, neutrophil extracellular trap (NET) formation, heterogeneity and plasticity, suppressive functions, and tissue injury have expanded our understanding of their diverse role in infection and inflammation. This review summarises our current understanding of neutrophils in host-pathogen interactions and disease involvement, illustrating the versatility and plasticity of the neutrophil, moving between host defence, immune modulation, and tissue damage.

Peroxisomal lipid synthesis regulates inflammation by sustaining neutrophil membrane phospholipid composition and viability

Fatty acid synthase (FAS) is altered in metabolic disorders and cancer. Conventional FAS null mice die in utero, so effects of whole-body inhibition of lipogenesis following development are unknown. Inducible global knockout of FAS (iFASKO) in mice was lethal due to a disrupted intestinal barrier and leukopenia. Conditional loss of FAS was associated with the selective suppression of granulopoiesis without disrupting granulocytic differentiation. Transplantation of iFASKO bone marrow into wild-type mice followed by Cre induction resulted in selective neutrophil depletion, but not death. Impaired lipogenesis increased ER stress and apoptosis in neutrophils by preferentially decreasing peroxisome-derived membrane phospholipids containing ether bonds. Inducible global knockout of PexRAP, a peroxisomal enzyme required for ether lipid synthesis, also produced neutropenia. FAS knockdown in neutrophil-like HL-60 cells caused cell loss that was partially rescued by ether lipids. Inhibiting ether lipid synthesis selectively constrains neutrophil development, revealing an unrecognized pathway in immunometabolism.