RESUMEN
PURPOSE: Chronic Lymphocytic Leukemia (CLL) is defined by a perturbed B-cell receptor-mediated signaling machinery. We aimed to model differential signaling behavior between B cells from CLL and healthy individuals to pinpoint modes of dysregulation. EXPERIMENTAL DESIGN: We developed an experimental methodology combining immunophenotyping, multiplexed phosphospecific flow cytometry, and multifactorial statistical modeling. Utilizing patterns of signaling network covariance, we modeled BCR signaling in 67 CLL patients using Partial Least Squares Regression (PLSR). Results from multidimensional modeling were validated using an independent test cohort of 38 patients. RESULTS: We identified a dynamic and variable imbalance between proximal (pSYK, pBTK) and distal (pPLCγ2, pBLNK, ppERK) phosphoresponses. PLSR identified the relationship between upstream tyrosine kinase SYK and its target, PLCγ2, as maximally predictive and sufficient to distinguish CLL from healthy samples, pointing to this juncture in the signaling pathway as a hallmark of CLL B cells. Specific BCR pathway signaling signatures that correlate with the disease and its degree of aggressiveness were identified. Heterogeneity in the PLSR response variable within the B cell population is both a characteristic mark of healthy samples and predictive of disease aggressiveness. CONCLUSION: Single-cell multidimensional analysis of BCR signaling permitted focused analysis of the variability and heterogeneity of signaling behavior from patient-to-patient, and from cell-to-cell. Disruption of the pSYK/pPLCγ2 relationship is uncovered as a robust hallmark of CLL B cell signaling behavior. Together, these observations implicate novel elements of the BCR signal transduction as potential therapeutic targets.
Asunto(s)
Regulación Leucémica de la Expresión Génica , Péptidos y Proteínas de Señalización Intracelular/genética , Leucemia Linfocítica Crónica de Células B/genética , Modelos Estadísticos , Fosfolipasa C gamma/genética , Proteínas Tirosina Quinasas/genética , Receptores de Antígenos de Linfocitos B/genética , Transducción de Señal , Anticuerpos Antiidiotipos/farmacología , Linfocitos B/efectos de los fármacos , Linfocitos B/metabolismo , Linfocitos B/patología , Citometría de Flujo , Humanos , Inmunofenotipificación , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Análisis de los Mínimos Cuadrados , Leucemia Linfocítica Crónica de Células B/metabolismo , Leucemia Linfocítica Crónica de Células B/patología , Activación de Linfocitos/efectos de los fármacos , Fosfolipasa C gamma/metabolismo , Fosforilación , Proteínas Tirosina Quinasas/metabolismo , Receptores de Antígenos de Linfocitos B/metabolismo , Análisis de la Célula Individual , Quinasa SykRESUMEN
We describe a method for stabilizing unstable steady states in nonlinear dynamical systems using a form of extended time-delay autosynchronization. Specifically, stabilization is achieved by applying a feedback signal generated by high-pass-filtering in real time the dynamical state of the system to an accessible system parameter or variables. Our technique is easy to implement, does not require knowledge of the unstable steady state coordinates in phase space, automatically tracks changes in the system parameters, and is more robust to broadband noise than previous schemes. We demonstrate the controller's efficacy by stabilizing unstable steady states in an electronic circuit exhibiting low-dimensional temporal chaos. The simplicity and robustness of the scheme suggests that it is ideally suited for stabilizing unstable steady states in ultra-high-speed systems. (c) 1998 American Institute of Physics.
