ABSTRACT
The genetic programs that maintain hematopoiesis during steady state in physiologic conditions are different from those activated during stress. Here, we show that hematopoietic stem cells (HSCs) with deficiencies in components of the alternative NFκB pathway (the NFκB inducing kinase, NIK, and the downstream molecule NFκB2) had a defect in response to stressors such as supraphysiological doses of cytokines, chemotherapy, and hematopoietic transplantation. NIK-deficient mice had peripheral blood and bone marrow leukocyte numbers within normal ranges (except for the already reported defects in B-cell maturation); however, HSCs showed significantly slower expansion capacity in in vitro cultures compared to wild-type HSCs. This was due to a delayed cell cycle and increased apoptosis. In vivo experiments showed that NIK-deficient HSCs did not recover at the same pace as controls when challenged with myeloablative chemotherapy. Finally, NIK-deficient HSCs showed a significantly decreased competitive repopulation capacity in vivo. Using HSCs from mice deficient in one of two downstream targets of NIK, that is, either NFκB2 or c-Rel, only NFκB2 deficiency recapitulated the defects detected with NIK-deficient HSCs. Our results underscore the role of NIK and the alternative NFκB pathway for the recovery of normal levels of hematopoiesis after stress.
Subject(s)
Hematopoiesis/physiology , Hematopoietic Stem Cells/enzymology , Protein Serine-Threonine Kinases/physiology , Stress, Physiological/physiology , Animals , Female , Mice , Mice, Inbred C57BL , Mice, Knockout , NF-kappa B p52 Subunit/physiology , NF-kappaB-Inducing KinaseABSTRACT
OBJECTIVES: Fibromyalgia (FM) has been associated with affective spectrum disorders and other chronic pain disorders, which tend to co-occur in individuals and co-aggregate among families. The objective of our study was to investigate the genetic risk factors associated with the presence of related symptoms and with disease severity in subjects affected with FM. METHODS: Two independent cohorts of subjects diagnosed with FM according to the 1990 ACR criteria were studied. A genetic array composed of 320 single nucleotide polymorphisms (SNPs) was analysed in a discovery cohort comprised by 564 patients, and the most suggestive variants were genotyped in a replication cohort, comprised by 397 subjects. The associated conditions and related symptoms analysed were: the presence of depression, sleep disorders, headache, myofascial syndrome, irritable bowel syndrome, chronic fatigue syndrome, vertiginous syndrome, chronic cystitis, and sicca syndrome. FM severity was assessed by the Fibromyalgia Impact Questionnaire and the Hospital Anxiety and Depression Scale. Analyses were adjusted by elapsed time from pain onset, and a meta-analysis was performed to pool the results. RESULTS: Minor allele of the rs3771863 SNP from the TACR1 gene showed a significant association with a lower risk of sicca syndrome (pooled and adjusted OR 0.56, [95%CI 0.42-0.76], p=0.00022). CONCLUSIONS: Our findings indicate a role of the TACR1 gene in the development of sicca syndrome in subjects affected with FM.
Subject(s)
Fibromyalgia/genetics , Polymorphism, Single Nucleotide , Receptors, Neurokinin-1/genetics , Sjogren's Syndrome/genetics , Adult , Comorbidity , Female , Fibromyalgia/diagnosis , Fibromyalgia/epidemiology , Gene Expression Profiling/methods , Gene Frequency , Genetic Association Studies , Genetic Predisposition to Disease , Humans , Male , Middle Aged , Odds Ratio , Oligonucleotide Array Sequence Analysis , Phenotype , Protective Factors , Risk Assessment , Risk Factors , Severity of Illness Index , Sjogren's Syndrome/diagnosis , Sjogren's Syndrome/epidemiology , Spain/epidemiology , Surveys and QuestionnairesABSTRACT
The transcription factor XBP1 (X-box-binding protein 1) is essential for plasma cell (PC) differentiation and immunoglobulin secretion. XBP1 is widely expressed, but its activity is precisely controlled by mRNA splicing in response to endoplasmic reticulum (ER) stress. It is the active form of XBP1, XBP1(S), which is required for PC differentiation. The relationship between XBP1(S) expression and PC differentiation in human tissue and its expression in hematologic malignancies has eluded assessment. With a novel antibody, we now define XBP1(S) expression in a large series of normal and neoplastic lymphoid tissues. We establish that XBP1(S) provides a specific marker of advanced plasma differentiation and in lymphoid malignancies is restricted to PC-derived neoplasms and plasmablastic diffuse large B-cell lymphomas. XBP1(S) expression delineates heterogeneity amongst plasmablastic diffuse large B-cell lymphomas, identifying a distinct tumor sub-group. Furthermore, our results establish a direct and practical means of assessing ER stress in human tumors.
