👤 Michelle L Seymour

Approximately 95% of lymphoplasmacytic lymphomas (LPL) are IgM secreting and are characterized as Waldenstrom Macroglobulinemia (WM). Conversely, non-IgM secreting LPL are rare. As part of the 12th International Workshop on WM (IWWM-12), a consensus panel of experts was tasked to develop recommendations for the management and response assessment of non-IgM LPL. The panel considered that in view of available molecular, pathological and clinical data, non-IgM LPL should be considered as a separate sub-entity of LPL. The panel further recommended that the IWWM-2 consensus criteria used for IgM LPL (WM) treatment initiation, should also be used for non-IgM LPL and be independent of IgG or IgA paraprotein level unless symptomatic hyperviscosity is present. The panel agreed that based on current evidence, there is insufficient data to support a different clinical management for non-IgM vs IgM (WM) LPL. Moreover, the panel advised that patients with non-IgM LPL should be treated in a similar manner to patients with IgM LPL independent of MYD88 mutation status until more is known about its impact on treatment outcomes for non-IgM LPL patients. The panel therefore recommends the use of the IWWM-11 IgM LPL (WM) response criteria for cases of non-IgM LPL with a monoclonal IgA or IgG paraprotein component, but creating a specific panel to develop formal response criteria for this LPL subset was also recommended. Show less

Neurodegenerative diseases characterized by aberrant accumulation of undigested cellular components represent unmet medical conditions for which the identification of actionable targets is urgently needed. Here we identify a pharmacologically actionable pathway that controls cellular clearance via Akt modulation of transcription factor EB (TFEB), a master regulator of lysosomal pathways. We show that Akt phosphorylates TFEB at Ser467 and represses TFEB nuclear translocation independently of mechanistic target of rapamycin complex 1 (mTORC1), a known TFEB inhibitor. The autophagy enhancer trehalose activates TFEB by diminishing Akt activity. Administration of trehalose to a mouse model of Batten disease, a prototypical neurodegenerative disease presenting with intralysosomal storage, enhances clearance of proteolipid aggregates, reduces neuropathology and prolongs survival of diseased mice. Pharmacological inhibition of Akt promotes cellular clearance in cells from patients with a variety of lysosomal diseases, thus suggesting broad applicability of this approach. These findings open new perspectives for the clinical translation of TFEB-mediated enhancement of cellular clearance in neurodegenerative storage diseases. Show less

Atonal homolog1 (Atoh1) encodes a basic helix-loop-helix protein that is the first transcription factor to be expressed in differentiating hair cells. Previous work suggests that expression of Atoh1 in prosensory precursors is necessary for the differentiation and survival of hair cells, but it is not clear whether Atoh1 is required exclusively for these processes, or whether it regulates other functions later during hair cell maturation. We used EGFP-tagged Atoh1 knock-in mice to demonstrate for the first time that Atoh1 protein is expressed in hair cell precursors several days before the appearance of differentiated markers, but not in the broad pattern expected of a proneural gene. We conditionally deleted Atoh1 at different points in hair cell development and observe a rapid onset of hair cell defects, suggesting that the Atoh1 protein is unstable in differentiating hair cells and is necessary through an extended phase of their differentiation. Conditional deletion of Atoh1 reveals multiple functions in hair cell survival, maturation of stereociliary bundles, and auditory function. We show the presence of distinct critical periods for Atoh1 in each of these functions, suggesting that Atoh1 may be directly regulating many aspects of hair cell function. Finally, we show that the supporting cell death that accompanies loss of Atoh1 in hair cells is likely caused by the abortive trans-differentiation of supporting cells into hair cells. Together our data suggest that Atoh1 regulates multiple aspects of hair cell development and function. Show less