Sonic hedgehog signaling regulates processes of embryonic development across multiple tissues, yet factors regulating context-specific Shh signaling remain poorly understood. Exome sequencing of families with polymicrogyria (disordered cortical folding) revealed multiple individuals with biallelic deleterious variants in TMEM161B , which encodes a multi-pass transmembrane protein of unknown function. Tmem161b null mice demonstrated holoprosencephaly, craniofacial midline defects, eye defects, and spinal cord patterning changes consistent with impaired Shh signaling, but were without limb defects, suggesting a CNS-specific role of Tmem161b. Tmem161b depletion impaired the response to Smoothened activation in vitro and disrupted cortical histogenesis in vivo in both mouse and ferret models, including leading to abnormal gyration in the ferret model. Tmem161b localizes non-exclusively to the primary cilium, and scanning electron microscopy revealed shortened, dysmorphic, and ballooned ventricular zone cilia in the Tmem161b null mouse, suggesting that the Shh-related phenotypes may reflect ciliary dysfunction. Our data identify TMEM161B as a regulator of cerebral cortical gyration, as involved in primary ciliary structure, as a regulator of Shh signaling, and further implicate Shh signaling in human gyral development.
New and emerging therapies for the treatment of relapsed/refractory diffuse large B-cell lymphoma
Diffuse large B-cell lymphoma (DLBCL) is the most common form of aggressive non-Hodgkin lymphoma. Approximately 40% of patients with DLBCL will experience disease relapse or will be refractory to first line chemoimmunotherapy, necessitating second-line salvage therapy. This has historically consisted of platinum-based chemotherapy regimens followed by autologous hematopoietic stem cell transplantation with curative intent for transplant-eligible patients or palliative chemotherapy for transplant-ineligible patients. In recent years there have been several new therapeutic agents approved for the treatment of relapsed/refractory DLBCL, thereby expanding the therapeutic landscape. These agents include polatuzumab vedotin, tafasitamab, loncastuximab tesirine, selinexor, and anti-CD19 chimeric antigen receptor T-cell therapies such as axicabtagene ciloleucel, tisagenlecleucel, and lisocabtagene maraleucel. This review summarizes the pharmacology, efficacy, safety, dosing, and administration of new agents recently approved for the treatment of relapsed/refractory DLBCL.