Relation of sensorimotor and cognitive cerebellum functional connectivity with brain structural damage in patients with multiple sclerosis and no disability.

BACKGROUND AND PURPOSE: To investigate the relationship between the functional connectivity (FC) of the sensorimotor and cognitive cerebellum and measures of structural damage in patients with multiple sclerosis (MS) and no physical disability. METHODS: We selected 144 relapsing-remitting MS patients with an Expanded Disability Status Scale score of ≤1.5 and 98 healthy controls from the Italian Neuroimaging Network Initiative database. From multimodal 3T magnetic resonance imaging (MRI), including functional MRI at rest, we calculated lesion load, cortical thickness, and white matter, cortical gray matter, and caudate, putamen, thalamic, and cerebellar volumes. Voxel-wise FC of the sensorimotor and cognitive cerebellum was assessed with seed-based analysis, and multiple regression analysis was used to evaluate the relationship between FC and structural damage. RESULTS: Whole brain, white matter, caudate, putamen, and thalamic volumes were reduced in patients compared to controls, whereas cortical gray matter was not significantly different in patients versus controls. Both the sensorimotor and cognitive cerebellum showed a widespread pattern of increased and decreased FC that were negatively associated with structural measures, indicating that the lower the FC, the greater the tissue loss. Lastly, among multiple structural measures, cortical gray matter and white matter volumes were the best predictors of cerebellar FC alterations. CONCLUSIONS: Increased and decreased cerebellar FC with several brain areas coexist in MS patients with no disability. Our data suggest that white matter loss hampers FC, whereas, in the absence of atrophy, cortical volume represents the framework for FC to increase.

A Pro-Regenerative Environment Triggers Premalignant to Malignant Transformation of Senescent Hepatocytes.

Unfortunately, available liver cancer treatments are associated with modest survival advantage. The biggest factor improving survival is early detection, but the current understanding of early transformation events is limited. Therefore, we set up a model to study these early events and investigated the relationship of premalignant, senescent hepatocytes, a regenerative environment, and the influence of secreted factors on liver tumorigenesis. Oncogene-induced senescence (OIS) was triggered in a subset of mouse hepatocytes, which under normal conditions, are eliminated by immunosurveillance. Inducing liver damage and regeneration was sufficient to trigger immunosurveillance escape of OIS hepatocytes, resulting in premalignant to malignant transformation and hepatocellular tumor development. Trefoil factor 3 (TFF3) was found to be overexpressed in OIS hepatocytes and in hepatocellular carcinoma. TFF3 deficiency strongly attenuated malignant transformation by increasing insulin-like growth factor binding protein 5 (IGFBP5) expression, which consequently dampened IGF receptor signaling. Furthermore, analysis of precancerous liver tissue validated TFF3 as an early liver cancer biomarker. Altogether, these findings provide mechanistic insights into early transformation and immunosurveillance escape in liver cancer, revealing TFF3 and IGFBP5 to be important players with opposite roles in tumorigenesis. SIGNIFICANCE: Liver damage induces a compensatory regenerative response that can drive premalignant to malignant transformation of senescent hepatocytes.

Mfap4: a promising target for enhanced liver regeneration and chronic liver disease treatment.

The liver has a remarkable regenerative capacity. Nevertheless, under chronic liver-damaging conditions, this capacity becomes exhausted, allowing the accumulation of fibrotic tissue and leading to end-stage liver disease. Enhancing the endogenous regenerative capacity by targeting regeneration breaks is an innovative therapeutic approach. We set up an in vivo functional genetic screen to identify such regeneration breaks. As the top hit, we identified Microfibril associated protein 4 (Mfap4). Knockdown of Mfap4 in hepatocytes enhances cell proliferation, accelerates liver regeneration, and attenuates chronic liver disease by reducing liver fibrosis. Targeting Mfap4 modulates several liver regeneration-related pathways including mTOR. Our research opens the way to siRNA-based therapeutics to enhance hepatocyte-based liver regeneration.

SALL4B, not targeted by IMiD, is important for SALL4-mediated tumorigenesis.

Oncofetal transcription factor SALL4 is essential for cancer cell survival. 1-5 Recently, several groups reported that immunomodulatory imide drugs (IMiDs) could degrade SALL4 in a proteasome-dependent manner. 6,7 Intriguingly, we observed that IMiDs had no effect on SALL4-positive cancer cells. Further studies demonstrated that IMiDs could only degrade SALL4A, one of the SALL4 isoforms. This finding raises the possibility that SALL4B, the isoform not affected by IMiDs, may be essential for SALL4-mediated cancer cell survival. SALL4B knockdown led to an increase in apoptosis and inhibition of cancer cell growth. SALL4B gain-of-function alone led to liver tumor formation in mice. Our observation that protein degraders can possess isoform-specific effects exemplifies the importance of delineating drug action and oncogenesis at the isoform level to develop more effective cancer therapeutics.