RESUMEN
The polymorphic major histocompatibility complex class I chain-related molecule A (MICA) and its soluble form (sMICA) interact with activating receptor natural-killer group 2 member D (NKG2D) on natural-killer (NK) and T cells, thereby modifying immune responses to transplantation and infectious agents (e.g., cytomegalovirus). Two single-nucleotide polymorphisms (SNPs), rs2596538GA in the MICA promoter and rs1051792AG in the coding region (MICA-129Val/Met), influence MICA expression or binding to NKG2D, with MICA-129Met molecules showing higher receptor affinity. To investigate the impact of these SNPs on the occurrence of cytomegalovirus infection or acute rejection (AR) in individuals who underwent simultaneous pancreasâ»kidney transplantation (SPKT), 50 recipient-donor pairs were genotyped, and sMICA levels were measured during the first year post-transplantation. Recipients with a Val-mismatch (recipient Met/Met and donor Val/Met or Val/Val) showed shorter cytomegalovirus infection-free and shorter kidney AR-free survival. Additionally, Val mismatch was an independent predictor of cytomegalovirus infection and kidney AR in the first year post-transplantation. Interestingly, sMICA levels were lower in rs2596538AA and MICA129Met/Met-homozygous recipients. These results provide further evidence that genetic variants of MICA influence sMICA levels, and that Val mismatch at position 129 increases cytomegalovirus infection and kidney AR risk during the first year post-SPKT.
Asunto(s)
Sustitución de Aminoácidos , Infecciones por Citomegalovirus/genética , Rechazo de Injerto/genética , Antígenos de Histocompatibilidad Clase I/genética , Subfamilia K de Receptores Similares a Lectina de Células NK/metabolismo , Adulto , Infecciones por Citomegalovirus/metabolismo , Femenino , Antígenos de Histocompatibilidad Clase I/metabolismo , Humanos , Trasplante de Riñón , Masculino , Persona de Mediana Edad , Trasplante de Páncreas , Pronóstico , Donantes de Tejidos , Valina/genéticaRESUMEN
BACKGROUND: Human leukocyte antigen-E (HLA-E) is a nonclassical major histocompatibility complex class I molecule that recently came into sharper focus as a putative marker of advanced tumor stages and disease progression. In solid tumors, increased HLA-E expression as well as elevated soluble HLA-E (sHLA-E) plasma levels are associated with a poor prognosis; however, a role for HLA-E in hematologic malignancies remains to be established. METHODS: The authors analyzed HLA-E alleles and sHLA-E levels in a cohort of 110 individuals with chronic lymphocytic leukemia (CLL). RESULTS: In patients with CLL, levels of sHLA-E increased with advanced disease stage (P = .01) and decreased after therapy (P = .01). Longitudinal follow-up revealed that both HLA-E*01:03 alleles and high levels of sHLA-E were significantly associated with a requirement for early treatment in patients with CLL (P = .027 and P = .023, respectively). In vitro, sHLA-E inhibited degranulation and interferon-γ production by natural killer (NK) cells when cocultivated with tumor cells. Moreover, sHLA-E loaded onto microspheres induced transforming growth factor-ß release by NK cells. Multivariate analysis revealed that the presence of at least 1 HLA-E*01:03 allele was an independent predictor of a requirement for early treatment. CONCLUSIONS: HLA-E alleles and sHLA-E levels may represent novel biomarkers for early disease progression in patients with CLL. Cancer 2017;123:814-23. © 2016 American Cancer Society.
Asunto(s)
Biomarcadores de Tumor/sangre , Progresión de la Enfermedad , Antígenos de Histocompatibilidad Clase I/genética , Leucemia Linfocítica Crónica de Células B/genética , Anciano , Alelos , Femenino , Genotipo , Antígenos de Histocompatibilidad Clase I/sangre , Humanos , Leucemia Linfocítica Crónica de Células B/sangre , Leucemia Linfocítica Crónica de Células B/patología , Leucocitos/patología , Masculino , Persona de Mediana Edad , Pronóstico , Antígenos HLA-ERESUMEN
The synaptonemal complex (SC) is a proteinaceous, meiosis-specific structure that is highly conserved in evolution. During meiosis, the SC mediates synapsis of homologous chromosomes. It is essential for proper recombination and segregation of homologous chromosomes, and therefore for genome haploidization. Mutations in human SC genes can cause infertility. In order to gain a better understanding of the process of SC assembly in a model system that would be relevant for humans, we are investigating meiosis in mice. Here, we report on a newly identified component of the murine SC, which we named SYCE3. SYCE3 is strongly conserved among mammals and localizes to the central element (CE) of the SC. By generating a Syce3 knockout mouse, we found that SYCE3 is required for fertility in both sexes. Loss of SYCE3 blocks synapsis initiation and results in meiotic arrest. In the absence of SYCE3, initiation of meiotic recombination appears to be normal, but its progression is severely impaired resulting in complete absence of MLH1 foci, which are presumed markers of crossovers in wild-type meiocytes. In the process of SC assembly, SYCE3 is required downstream of transverse filament protein SYCP1, but upstream of the other previously described CE-specific proteins. We conclude that SYCE3 enables chromosome loading of the other CE-specific proteins, which in turn would promote synapsis between homologous chromosomes.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Fertilidad , Meiosis , Proteínas Nucleares/metabolismo , Complejo Sinaptonémico/fisiología , Proteínas Adaptadoras Transductoras de Señales/genética , Secuencia de Aminoácidos , Animales , Proteínas Cromosómicas no Histona/genética , Proteínas Cromosómicas no Histona/metabolismo , Clonación Molecular , Intercambio Genético , Proteínas de Unión al ADN , Femenino , Genotipo , Masculino , Ratones , Ratones Noqueados , Datos de Secuencia Molecular , Homólogo 1 de la Proteína MutL , Proteínas Nucleares/genética , Ovario/metabolismo , Ovario/ultraestructura , Unión Proteica , Alineación de Secuencia , Espermatocitos/metabolismo , Testículo/metabolismo , Testículo/ultraestructura , TransfecciónRESUMEN
The synaptonemal complex (SC) is a proteinaceous structure of chromosome bivalents whose assembly is indispensable for the successful progression of the first meiotic division of sexually reproducing organisms. In this mini-review we will focus on recent progress dealing with the composition and assembly of the mammalian SC. These advances mainly resulted from the systematic use of knockout mice for all known mammalian SC proteins as well as from protein polymerization studies performed in heterologous systems.
Asunto(s)
Mamíferos/fisiología , Meiosis/fisiología , Multimerización de Proteína/fisiología , Recombinación Genética/fisiología , Complejo Sinaptonémico/fisiología , Animales , Humanos , Mamíferos/genética , Mamíferos/metabolismo , Meiosis/genética , Ratones , Ratones Noqueados , Modelos Biológicos , Multimerización de Proteína/genética , Subunidades de Proteína/genética , Subunidades de Proteína/metabolismo , Subunidades de Proteína/fisiología , Recombinación Genética/genética , Complejo Sinaptonémico/genética , Complejo Sinaptonémico/metabolismoRESUMEN
The immunosuppressive non-classical human leukocyte antigen-G (HLA-G) can elicits pro-viral activities by down-modulating immune responses. We analysed soluble forms of HLA-G, IL-6 and IL-10 as well as on immune effector cell expression of HLA-G and its cognate ILT-2 receptor in peripheral blood obtained from hospitalised and convalescent COVID-19 patients. Compared with convalescents (N = 202), circulating soluble HLA-G levels (total and vesicular-bound molecules) were significantly increased in hospitalised patients (N = 93) irrespective of the disease severity. During COVID-19, IL-6 and IL-10 levels were also elevated. Regarding the immune checkpoint expression of HLA-G/ILT-2 on peripheral immune effector cells, the frequencies of membrane-bound HLA-G on CD3+ and CD14+ cells were almost identical in patients during and post COVID-19, while the frequency of ILT-2 receptor on CD3+ and CD14+ cells was increased during acute infection. A multi-parametric correlation analysis of soluble HLA-G forms with IL-6, IL-10, activation markers CD25 and CD154, HLA-G, and ILT-2 expression on immune cells revealed a strong positive correlation of soluble HLA-G forms with membrane-bound HLA-G molecules on CD3+/CD14+ cells only in convalescents. During COVID-19, only vesicular-bound HLA-G were positively correlated with the activation marker CD25 on T cells. Thus, our data suggest that the elevated levels of soluble HLA-G in COVID-19 are due to increased expression in organ tissues other than circulating immune effector cells. The concomitant increased expression of soluble HLA-G and ILT-2 receptor frequencies supports the concept that the immune checkpoint HLA-G/ILT-2 plays a role in the immune-pathogenesis of COVID-19.
Asunto(s)
COVID-19 , Antígenos HLA-G , Humanos , COVID-19/metabolismo , Antígenos HLA-G/metabolismo , Interleucina-10/metabolismo , Interleucina-6/metabolismo , Linfocitos TRESUMEN
Introduction: Triple negative breast cancer (TNBC) shows an aggressive growing and spreading behavior and has limited treatment options, often leading to inferior disease outcome. Therefore, surrogate markers are urgently needed to identify patients at high risk of recurrence and more importantly, to identify additional therapeutic targets enabling further treatment options. Based on the key role of the non-classical human leukocyte antigen G (HLA-G) and its related receptor immunoglobulin-like transcript receptor-2 (ILT-2) in immune evasion mechanisms of tumors, members of this ligand-receptor axis appear to be promising tool for both, defining risk groups and potential therapeutic targets. Materials and methods: To follow this, sHLA-G levels before and after chemotherapy (CT), HLA-G 3' UTR haplotypes, and allele variations rs10416697 at the distal gene promoter region of ILT-2 were defined in healthy female controls and early TNBC patients. The results obtained were associated with clinical status, presence of circulating tumor cell (CTC) subtypes, and disease outcome of patients in terms of progression-free or overall survival. Results: sHLA-G plasma levels were increased in TNBC patients post-CT compared to levels of patients pre-CT or controls. High post-CT sHLA-G levels were associated with the development of distant metastases, the presence of ERCC1 or PIK3CA-CTC subtypes post-CT, and poorer disease outcome in uni- or multivariate analysis. HLA-G 3' UTR genotypes did not influence disease outcome but ILT-2 rs10416697C allele was associated with AURKA-positive CTC and with adverse disease outcome by uni- and multivariate analysis. The prognostic value of the combined risk factors (high sHLA-G levels post-CT and ILT-2 rs10416697C allele carrier status) was an even better independent indicator for disease outcome in TNBC than the lymph nodal status pre-CT. This combination allowed the identification of patients with high risk of early progression/death with positive nodal status pre-CT or with non-pathological complete therapy response. Conclusion: The results of this study highlight for the first time that the combination of high levels of sHLA-G post-CT with ILT-2 rs10416697C allele receptor status is a promising tool for the risk assessment of TNBC patients and support the concept to use HLA-G/ILT-2 ligand-receptor axis as therapeutic targets.
Asunto(s)
Neoplasias de la Mama Triple Negativas , Humanos , Femenino , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico , Neoplasias de la Mama Triple Negativas/genética , Antígenos HLA-G/genética , Alelos , Regiones no Traducidas 3'/genética , LigandosRESUMEN
The human leukocyte antigen G (HLA-G) is an immune checkpoint molecule with a complex network of interactions with several inhibitory receptors. Although the effect of HLA-G on T cells and NK cells is well studied, the effect of HLA-G on B cells is still largely elusive. B cells are of particular interest in the context of the HLA-G-ILT-2 interaction because the ILT-2 receptor is constitutively expressed on most B cells, whereas it is only present on some subsets of T and NK cells. To characterize the effect of HLA-G5 molecules on B cells, we studied splenic B cells derived from cytomegalovirus (CMV) sero-positive donors after CMV stimulation with antigens in the presence and absence of soluble HLA-G5. In the presence of HLA-G5, increased expression of the ITIM-bearing Ig-like transcript (ILT-2) was observed on B cells, but its expression was not affected by stimulation with CMV antigens. Moreover, it became evident that HLA-G5 exposure resulted in a decreased expression of CD27 and CD38 and, accordingly, in lower proportions of CD19+CD27+CD38+ and higher proportions of CD19+CD27-CD38- B cells. Taken together, our in vitro findings demonstrate that soluble HLA-G5 suppresses markers of B cell activation, suggesting that HLA-G5 has an impact on splenic B cell differentiation and activation. Based on these results, further investigation regarding the role of HLA-G as a prognostic factor and a potential therapeutic agent with respect to B cell function appears reasonable.
Asunto(s)
Linfocitos B , Antígenos HLA-G , Proteínas de Punto de Control Inmunitario , ADP-Ribosil Ciclasa 1 , Antígenos CD , Linfocitos B/inmunología , Infecciones por Citomegalovirus , Humanos , Receptor Leucocitario Tipo Inmunoglobulina B1 , Activación de Linfocitos , Bazo/citología , Miembro 7 de la Superfamilia de Receptores de Factores de Necrosis TumoralRESUMEN
Aggressive B-cell lymphomas account for the majority of non-Hodgkin lymphomas (B-NHL). NK cells govern the responses to anti-CD20 monoclonal antibodies and have emerged as attractive targets for immunotherapy in subtypes of B-NHL. NKG2C and its cognate ligand HLA-E represent key molecules for fine-tuning of NK cell-mediated immune responses. Here, we investigated the impact of genetic variants of NKG2C and HLA-E on clinical outcomes of 441 B-NHL patients. Homozygous deletion of NKG2C (NKG2C-/-) was three-fold increased in patients compared to 192 healthy controls. Among studied patients, NKG2C-/- was more abundant in International Prognostic Index (IPI) high-risk patients compared to patients with a lower IPI (p = 0.013). Strikingly, NKG2C-/- was associated with a significantly reduced 2-year PFS (progression-free survival) (p = 0.0062) and represented an independent risk factor for 2-year PFS in multivariate analysis (p = 0.005). For HLA-E, the cognate ligand of NKG2C, the HLA-E*01:01 allele frequency was increased in B-NHL patients compared to controls (p = 0.033) and was associated with complete remission in univariate (p = 0.034) and multivariate (p = 0.018) analysis. Our data suggest that NKG2C and HLA-E genotyping is a promising tool for both defining risk groups of aggressive B-NHL and predicting response to immune therapeutic approaches.
RESUMEN
The immunosuppressive non-classical human leukocyte antigen-G (HLA-G) promotes transplant tolerance as well as viral immune escape. HLA-G expression is associated with regulatory elements targeting certain single nucleotide polymorphisms (SNPs) in the HLA-G 3' untranslated region (UTR). Thus, we evaluated the impact of HLA-G 3'UTR polymorphisms as surrogate markers for BK polyomavirus (BKPyV) replication or nephropathy (PyVAN) and acute cellular and antibody mediated rejection (ACR/AMR) in 251 living-donor kidney-transplant recipient pairs. After sequencing of the HLA-G 3'UTR, fourteen SNPs between +2960 and +3227 and the 14â¯bp insertion/deletion polymorphism, which arrange as UTR haplotypes, were identified. The UTR-4 haplotype in donors and recipients was associated with occurrence of BKPyV/PyVAN compared to the other UTR haplotypes. While the UTR-4 recipient haplotype provided protection against AMR, the UTR-2 donor haplotype was deleteriously associated with ACR/AMR. Deduction of the UTR-2/4 haplotypes to specific SNPs revealed that the +3003C variant (unique for UTR-4) in donors as well as in recipients is responsible for BKPyV/PyVAN and also provides protection against AMR; whereas the +3196G variant (unique for UTR-2) promotes allograft rejection. Thus, HLA-G 3'UTR variants are promising genetic predisposition markers both in donors and recipients that may help to predict susceptibility to either viral infectious complication of BKPyV or allograft rejection.
Asunto(s)
Virus BK/fisiología , Rechazo de Injerto/genética , Antígenos HLA-G/genética , Trasplante de Riñón/efectos adversos , Donadores Vivos , Regiones no Traducidas 3' , Adulto , Femenino , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad/genética , Genotipo , Rechazo de Injerto/inmunología , Humanos , Enfermedades Renales/genética , Enfermedades Renales/virología , Masculino , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple , Pronóstico , Replicación ViralRESUMEN
Human leukocyte antigen (HLA)-E is important for the regulation of anti-viral immunity. BK polyomavirus (BKPyV) reactivation after kidney transplant is a serious complication that can result in BKPyV-associated nephropathy (PyVAN) and subsequent allograft loss. To elucidate whether HLA-E polymorphisms influence BKPyV replication and nephropathy, we determined the HLA-E genotype of 278 living donor and recipient pairs. A total of 44 recipients suffered from BKPyV replication, and 11 of these developed PyVAN. Homozygosity of the recipients for the HLA-E*01:01 genotype was associated with the protection against PyVAN after transplant (p = 0.025, OR 0.09, CI [95%] 0.83-4.89). Considering the time course of the occurrence of nephropathy, recipients with PyVAN were more likely to carry the HLA-E*01:03 allelic variant than those without PyVAN (Kaplan-Meier analysis p = 0.03; OR = 4.25; CI (95%) 1.11-16.23). Our findings suggest that a predisposition based on a defined HLA-E genotype is associated with an increased susceptibility to develop PyVAN. Thus, assessing HLA-E polymorphisms may enable physicians to identify patients being at an increased risk of this viral complication.
Asunto(s)
Predisposición Genética a la Enfermedad , Antígenos de Histocompatibilidad Clase I/genética , Enfermedades Renales/prevención & control , Trasplante de Riñón , Infecciones por Polyomavirus , Adulto , Anciano , Alelos , Femenino , Humanos , Donadores Vivos , Masculino , Persona de Mediana Edad , Infecciones por Polyomavirus/genética , Infecciones por Polyomavirus/prevención & control , Antígenos HLA-ERESUMEN
The non-classical human leukocyte antigen G (HLA-G) molecule and its soluble forms exert multiple immune suppressive regulatory functions in malignancy and in stem cells contributing to immune escape mechanisms. HLA-G can be secreted as free soluble HLA-G molecules or via extracellular vesicles (EVs). Here we evaluated these soluble HLA-G forms as prognostic marker for prediction of the clinical outcome of neoadjuvant chemotherapy (NACT) treated breast cancer (BC) patients. Plasma samples of BC patients procured before (n=142) and after (n=154) NACT were quantified for total soluble HLA-G (sHLA-Gtot) and HLA-G levels in ExoQuick™ derived EV fractions (sHLA-GEV) by ELISA. The corresponding increments were specified as free sHLA-G (sHLA-Gfree). Total and free sHLA-G were significantly increased in NACT treated BC patients compared to healthy controls (n=16). High sHLA-Gfree levels were exclusively associated to estrogen receptor expression before NACT. Importantly, high sHLA-GEV levels before NACT were related to disease progression and the detection of stem cell-like circulating tumor cells, but high sHLA-Gfree levels indicated an improved clinical outcome. Thus, this study demonstrates for the first time that the different sHLA-G subcomponents represent dissimilar qualitative prognostic impacts on the clinical outcome of NACT treated BC patients, whereas the total sHLA-G levels without separating into subcomponents are not related to clinical outcome.
Asunto(s)
Proteínas Sanguíneas/metabolismo , Neoplasias de la Mama/diagnóstico , Carcinoma Ductal/diagnóstico , Micropartículas Derivadas de Células/metabolismo , Antígenos HLA-G/metabolismo , Células Neoplásicas Circulantes/patología , Células Madre Neoplásicas/patología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Neoplasias de la Mama/tratamiento farmacológico , Carcinoma Ductal/tratamiento farmacológico , Progresión de la Enfermedad , Femenino , Humanos , Persona de Mediana Edad , Terapia Neoadyuvante , Pronóstico , Resultado del Tratamiento , Escape del Tumor , Adulto JovenRESUMEN
During recent years a number of severe clinical syndromes, collectively termed laminopathies, turned out to be caused by various, distinct mutations in the human LMNA gene. Arising from this, remarkable progress has been made to unravel the molecular pathophysiology underlying these disorders. A great benefit in this context was the generation of an A-type lamin deficient mouse line (Lmna (-/-) ) by Sullivan and others, ( 1) which has become one of the most frequently used models in the field and provided profound insights to many different aspects of A-type lamin function. Here, we report the unexpected finding that these mice express a truncated Lmna gene product on both transcriptional and protein level. Combining different approaches including mass spectrometry, we precisely define this product as a C-terminally truncated lamin A mutant that lacks domains important for protein interactions and post-translational processing. Based on our findings we discuss implications for the interpretation of previous studies using Lmna (-/-) mice and the concept of human laminopathies.
Asunto(s)
Lamina Tipo A/metabolismo , Animales , Anticuerpos/inmunología , Secuencia de Bases , Línea Celular , Exones , Lamina Tipo A/deficiencia , Lamina Tipo A/genética , Hígado/metabolismo , Ratones , Ratones Noqueados , Mutación , Membrana Nuclear/metabolismo , Procesamiento Proteico-PostraduccionalRESUMEN
A hallmark of meiosis is the precise pairing and the stable physical connection (synapsis) of the homologous chromosomes. These processes are essential prerequisite for their proper segregation. Pairing of the homologs during meiotic prophase I critically depends on characteristic movements of chromosomes. These movements, in turn, require attachment of meiotic telomeres to the nuclear envelope and their subsequent dynamic repositioning. Dynamic repositioning of meiotic telomeres goes along with profound structural reorganization of the nuclear envelope. The short A-type lamin C2 is thought to play a critical role in this process due to its specific expression during meiotic prophase I and the unique localization surrounding telomere attachments. Consistent with this notion, here we provide compelling evidence that meiosis-specific lamin C2 features a significantly increased mobility compared to somatic lamins as revealed by photobleaching techniques. We show that this property can be clearly ascribed to the lack of the N-terminal head and the significantly shorter α-helical coil domain. Moreover, expression of lamin C2 in somatic cells induces nuclear deformations and alters the distribution of the endogenous nuclear envelope proteins lamin B1, LAP2, SUN1 and SUN2. Together, our data define lamin C2 as a "natural lamin deletion mutant" that confers unique properties to the nuclear envelope which would be essential for dynamic telomere repositioning during meiotic prophase I.