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TAR DNA-binding protein 43 (TDP-43) is an evolutionarily conserved RNA/DNA-binding protein that is nuclear-enriched in healthy cells, but deposited in the cytoplasm as aggregates in affected neurons in certain neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). We have previously developed an optogenetic TDP-43 variant (opTDP-43h) whose oligomerization status can be modulated via the CRY2olig tag, which self-assembles upon absorption of blue light. Illumination of zebrafish spinal motor neurons expressing opTDP-43h with a blue light triggers its cytoplasmic mislocalization, eventually leading to cytoplasmic deposition of opTDP-43h aggregates. Intriguingly, a light illumination-dependent transient opTDP-43 mislocalization can halt motor axon outgrowth, even in the absence of cytoplasmic deposition of opTDP-43 aggregates. These observations point toward an oligomerization-dependent, but aggregation-independent, cytotoxic effect of TDP-43 that might contribute to pathogenesis of ALS. In the present review, we would like to overview the zebrafish ALS model based on the optogenetic TDP-43, and then discuss about the potential mechanisms of TDP-43 cytotoxicity that trigger and/or promote motor neuron degeneration in ALS.

Progress in strategies aimed at breaking down therapeutic target proteins has led to a paradigm shift in drug discovery. Thalidomide and its derivatives are the only protein degraders currently used in clinical practice. Our understanding of the molecular mechanism of action of thalidomide and its derivatives has advanced dramatically since the identification of cereblon (CRBN) as their direct target. The binding of thalidomide derivatives to CRBN, a substrate recognition receptor for Cullin 4 RING E3 ubiquitin ligase (CRL4), induces the recruitment of non-native substrates to CRL4

Spinal motor neurons (SMNs) are the primary target of degeneration in amyotrophic lateral sclerosis (ALS). Degenerating motor neurons accumulate cytoplasmic TAR DNA-binding protein 43 (TDP-43) aggregates in most ALS cases. This SMN pathology can occur without mutation in the coding sequence of the TDP-43-encoding gene, TARDBP. Whether and how wild-type TDP-43 drives pathological changes in SMNs in vivo remain largely unexplored. In this study, we develop a two-photon calcium imaging setup in which tactile-evoked neural responses of motor neurons in the brainstem and spinal cord can be monitored using the calcium indicator GCaMP. We devise a piezo-assisted tactile stimulator that reproducibly evokes a brainstem descending neuron upon tactile stimulation of the head. A direct comparison between caudal primary motor neurons (CaPs) with or without TDP-43 overexpression in contiguous spinal segments demonstrates that CaPs overexpressing TDP-43 display attenuated Ca2+transients during fictive escape locomotion evoked by the tactile stimulation. These results show that excessive amounts of TDP-43 protein reduce the neuronal excitability of SMNs and potentially contribute to asymptomatic pathological lesions of SMNs and movement disorders in patients with ALS.

We previously showed that the interaction of programmed death-ligand 1 (PD-L1) on multiple myeloma (MM) cells with PD-1 not only inhibits tumor-specific cytotoxic T-lymphocyte activity via the PD-1 signaling pathway but also induces drug resistance via PD-L1–mediated reverse signals. We here examined the regulation of PD-L1 expression by immunomodulatory drugs (IMiDs) and antimyeloma effects of the anti–PD-L1 antibody durvalumab in combination with IMiDs. IMiDs induced PD-L1 expression on IMiD-insensitive MM cells and plasma cells from patients newly diagnosed with MM. Gene-expression profiling analysis demonstrated that not only PD-L1, but also a proliferation-inducing ligand (APRIL), was enhanced by IMiDs. PD-L1 induction by IMiDs was suppressed by using the APRIL inhibitor recombinant B-cell maturation antigen (BCMA)-Ig, the antibody against BCMA, or an MEK/ERK inhibitor in in vitro and in vivo assays. In addition, its induction was abrogated in cereblon (CRBN)-knockdown MM cells, whereas PD-L1 expression was increased and strongly induced by IMiDs in Ikaros-knockdown cells. These results demonstrated that PD-L1 upregulation by IMiDs on IMiD-insensitive MM cells was induced by (i) the BCMA–APRIL pathway via IMiD-mediated induction of APRIL and (ii) Ikaros degradation mediated by CRBN, which plays a role in inhibiting PD-L1 expression. Furthermore, T-cell inhibition induced by PD-L1–upregulated cells was effectively recovered after combination treatment with durvalumab and IMiDs. PD-L1 upregulation by IMiDs on MM cells might promote aggressive myeloma behaviors and immune escape in the bone marrow microenvironment.

Supplementary Materials and methods; Supplementary Table S1: Cell characteristics and phenotypes of MM cell lines; Supplementary Table S2: Characteristics of patients with newly diagnosed MM in Figure 1H; Supplementary Table S3: Primer and shRNA sequence; Supplementary Table S4: Four hundred four genes differentially expressed in MM cell lines treated with or without POM; Supplementary Figure S1: Antitumor effect of LEN and POM on MM cell lines; Supplementary Figure S2: Relationship of POM sensitivity with CRBN expression; Supplementary Figure S3: DNA copy numbers of PD-L1 in MM cell lines; Supplementary Figure S4: The level of cell-surface expression of PD-L2; Supplementary Figure S5: Cell-surface expression of BCMA and TACI on MM cell lines treated with IMiDs; Supplementary Figure S6: Enrichment plots for the gene sets of the MAPK/ERK pathway; Supplementary Figure S7: In vivo analysis using a murine xenograft model of human myeloma MM.1S cells inoculated into the flanks of NOG mice; Supplementary Figure S8: PD-L1 mRNA expression in CRBN-knockout and Ikaros- and Aiolos-knockdown cells after 3-day cultivation with LEN or POM; Supplementary Figure S9: Ikaros binding sites in the promoter of the PD-L1 gene; Supplementary Figure S10: Cell proliferation and T-cell activation of CD8+ T cells on day 4 when co-cultivation of T cells with untreated or LEN-pretreated U266 cells was treated with durvalumab and LEN; Supplementary Figure S11: APRIL protein and mRNA expression in CRBN-knockout and Ikaros- and Aiolos-knockdown MOSTI-1 cells after 3-day cultivation with LEN or POM.

Table S1. Primer sequences Table S2. Patient characteristics in cell - surface SLAMF3 and CD138 expression analysis. Table S3. One hundred and sixty-eight gene sets that were significantly upregulated in SLAMF3-KMS34 cells compared with Î"SLAMF3 cells (NOM P-value

The phase II study of tirabrutinib monotherapy at a daily dose of 480 mg under fasting conditions for treatment-naïve and relapsed/refractory Waldenström's macroglobulinemia (ONO-4059-05 study) demonstrated a promising efficacy and tolerable safety profile. We conducted an unplanned analysis with a median follow-up of 24.8 months to update the efficacy and safety results and to report patient-reported quality of life. Of 27 enrolled patients, 22 patients continued receiving the study drug. The major response assessed by an independent review committee was observed in 25 patients (93%), including one and five patients who newly achieved complete response and very good partial response, respectively, after the primary analysis. The progression-free and overall survival rates at 24 months were 92.6% and 100%, respectively. Serum IgM levels in all patients except one declined and were maintained at low levels, although transient increases occurred after temporal interruption of the study drug. The disease-related symptoms including recurrent fever and hyperviscosity mostly disappeared. Health-related quality of life, assessed by cancer-specific questionnaires, was mostly maintained. Grade 3-4 neutropenia, lymphopenia, and leukopenia were newly recognized in three, two, and one patient, respectively. Grade 3 treatment-related hypertriglyceridemia was also recognized. Nine patients experienced grade 1-2 bleeding events (33%), one patient experienced grade 2 treatment-related atrial fibrillation, and one patient experienced grade 1 treatment-related hypertension. Treatment-related skin adverse events were observed in 14 patients (52%). Taken together, tirabrutinib has durable efficacy with an acceptable safety profile for treatment-naïve and refractory/relapsed Waldenström's macroglobulinemia.

Supplementary Figure 1 from 17β-Hydroxysteroid Dehydrogenase Type 12 in Human Breast Carcinoma: A Prognostic Factor via Potential Regulation of Fatty Acid Synthesis

Supplementary Figure 2 from 17β-Hydroxysteroid Dehydrogenase Type 12 in Human Breast Carcinoma: A Prognostic Factor via Potential Regulation of Fatty Acid Synthesis

Supplementary Figure Legends 1-2 from 17β-Hydroxysteroid Dehydrogenase Type 12 in Human Breast Carcinoma: A Prognostic Factor via Potential Regulation of Fatty Acid Synthesis

17β-Hydroxysteroid dehydrogenase type 12 (17β-HSD12) has been shown to be involved in elongation of very long chain fatty acid (VLCFA) as well as in biosynthesis of estradiol (E2). 17β-HSD12 expression was also reported in breast carcinomas but its functions have remained unknown. In this study, we examined the correlation between mRNA expression profiles determined by microarray analysis and tissue E2 concentrations obtained from 16 postmenopausal breast carcinoma cases. No significant correlations were detected between 17β-HSD12 expression and E2 concentration. We then immunolocalized this enzyme in 110 cases of invasive ductal carcinoma. 17β-HSD12 immunoreactivity in breast carcinoma cells was significantly associated with poor prognosis of the patients. We further examined the biological significance of 17β-HSD12 using cell-based studies. Small interfering RNA–mediated knockdown of 17β-HSD12 in SK-BR-3 (estrogen receptor–negative breast carcinoma cell line) resulted in significant growth inhibition, which was recovered by the addition of VLCFAs such as arachidonic acid. The status of 17β-HSD12 immunoreactivity was also correlated with adverse clinical outcome in cyclooxygenase 2 (COX2)–positive breast cancer patients but not in COX2-negative patients. Therefore, these findings indicated that 17β-HSD12 was not necessarily related to intratumoral E2 biosynthesis, at least in human breast carcinoma, but was rather correlated with production of VLCFAs such as arachidonic acid, which may subsequently be metabolized to prostaglandins by COX2 and result in tumor progression of the patients. [Cancer Res 2009;69(4):1392–9]

Supplementary Table 1 from 17β-Hydroxysteroid Dehydrogenase Type 12 in Human Breast Carcinoma: A Prognostic Factor via Potential Regulation of Fatty Acid Synthesis

Azacitidine is a mainstay of therapy for MDS-related diseases. The purpose of our study is to elucidate the effect of gene mutations on hematological response and overall survival (OS), particularly focusing on their post-treatment clone size. We enrolled a total of 449 patients with MDS or related myeloid neoplasms. They were analyzed for gene mutations in pre- (n=449) and post- (n=289) treatment bone marrow samples using targeted-capture sequencing to assess the impact of gene mutations and their post-treatment clone size on treatment outcomes. In Cox proportional hazard modeling, multi-hit TP53 mutation (HR, 2.03; 95% CI, 1.42-2.91; P

Introduction Waldenström macroglobulinemia (WM) represents a subset of lymphoplasmacytic lymphoma (LPL) with the immunoglobulin (Ig)M paraprotein. MYD88 L265P and CXCR4 mutations are common mutations in WM patients, and mutations in ARID1A and KMT2D (MLL2) have also been reported. However, little information has been accumulated on genetic changes in LPL with other paraproteins like IgG. Methods We therefore aimed to evaluate genetic differences between WM and LPL with non-IgM paraprotein (non-IgM-type LPL) using targeted next-generation sequencing (NGS) in 20 Japanese patients (10 with WM, 10 with non-IgM-type LPL). Results Mutations were detected in ARID1A (10%), CXCR4 (20%), MYD88 (90%), and KMT2D (0%) for WM patients, and in ARID1A (10%), CXCR4 (20%), MYD88 (70%), and KMT2D (10%) for non-IgM-type LPL patients. No significant differences were identified. No mutations were detected in NOTCH2, PRDM1, CD274 (PD-L1), PDCD1LG2 (PD-L2), RAG2, MYBBP1A, TP53, or CD79B. Discussion Mutant allele frequency in MYD88 L265P did not differ significantly between WM and non-IgM-type LPL. Most mutations detected by NGS were subclonal following MYD88 L265P, although one non-IgM-type LPL patient harbored only CXCR4 S338X mutation. Our NGS analyses reveal genetic characteristics in LPL patients and suggest genetic similarities between these two subsets of LPL, WM and non-IgM-type.

The eye and brain are composed of elaborately organized tissues, development of which is supported by spatiotemporally precise expression of a number of transcription factors and developmental regulators. Here we report the molecular and genetic characterization of Integrator complex subunit 15 (INTS15). INTS15 was identified in search for the causative gene(s) for an autosomal-dominant eye disease with variable individual manifestation found in a large pedigree. While homozygous INTS15 knockout mice are embryonic lethal, mutant mice lacking a small C-terminal region of INTS15 show ocular malformations similar to the human patients. INTS15 is highly expressed in the eye and brain during embryogenesis and stably interacts with the Integrator complex to support snRNA 3′ end processing. Its knockdown resulted in missplicing of a large number of genes, probably as a secondary consequence, and substantially affected genes associated with eye and brain development. Moreover, studies using human iPS-derived neural progenitor cells showed that INTS15 is critical for axonal outgrowth in retinal ganglion cells. This study suggests a new link between general transcription machinery and a highly specific hereditary disease.

Reduction of blood group ABO antigens on red blood cells (RBCs) is well known in patients with leukemias, and this reduction of ABO expression is strongly associated with DNA methylation of the ABO promoter. Previously, we reported a two-nucleotide deletion in RUNX1 encoding an abnormally elongated protein lacking the trans-activation domain in a patient with myelodysplastic syndrome (MDS) showing A-antigen loss on RBCs. This prompted us to investigate the underlying mechanism responsible for A-antigen reduction on RBCs in another patient with MDS.Screening of somatic mutations was carried out using a targeted sequencing panel with genomic DNA from peripheral blood mononuclear cells from the patient and eleven MDS controls without A- or B-antigen loss. DNA methylation of the ABO promoter was examined by bisulfite genomic sequencing. Transient transfection assays were performed for functional evaluation of mutations.Screening of somatic mutations showed missense mutations in RUNX1 and GATA2 in the patient, while no mutation was found in exons of those genes in the controls. There was no significant difference in ABO promoter methylation between the patient and the controls. Transient transfection experiments into COS-7 and K562 cells suggested that the amino acid substitutions encoded by those mutations reduced or lost the trans-activation potential of the ABO expression.Considering the discrepancy between the variant frequencies of these mutations and the ratios of the RBCs with A-antigens loss, the antigen reduction might be associated with these somatic mutations and hypermethylation of the ABO promoter.

A 70-year-old man with multicentric Castleman disease (MCD) was admitted to our hospital with jaundice and ascites. Elevations in his bilirubin and interleukin-6 levels were noted, and computed tomography revealed hepatic atrophy and portal vein and bile duct disorders. Steroid therapy was started for MCD, but he died of hepatic failure. An autopsy revealed that the MCD activity was mild, but advanced fibrosis and cholestasis were observed in the liver. Mild infiltration of interleukin-6-positive plasma cells was noted in the highly fibrotic area of the liver. Although rare, liver and biliary tract damage may be also considered organ disorders of MCD.

Pomalidomide and lenalidomide are immunomodulatory agents that were derived from thalidomide. Cereblon (CRBN) is a common direct target of thalidomide and related compounds and works as a Cullin Ring 4 E3 ubiquitin ligase (CRL4) with DDB1, CUL4, and ROC1. The substrate specificity of CRL4CRBN is modulated by thalidomide-related compounds. While lenalidomide is approved for the treatment of several diseases including multiple myeloma, 5q- syndrome, mantle cell lymphoma, and follicular lymphoma, pomalidomide is approved only for the treatment of lenalidomide-resistant multiple myeloma. Here we show that PLZF/ZBTB16 and its fusion proteins are pomalidomide-dependent neosubstrates of CRL4CRBN. PLZF joins to RARα or potentially other partner genes, and the translocation causes leukemias, such as acute promyelocytic leukemia and T-cell acute lymphoblastic leukemia. We demonstrate that pomalidomide treatment induces PLZF-RARα degradation, resulting in antiproliferation of leukemic cells expressing PLZF-RARα. This study highlights a potential therapeutic role of pomalidomide as a degrader of leukemogenic fusion proteins., Shimizu et al. identify PLZF/ZBTB16 and its fusion proteins as pomalidomide-dependent neosubstrates of the cereblon E3 ligase. The authors also report that pomalidomide induces their degradation and thereby exerts its anti-cancer effect in leukemic cells expressing the fusion proteins.

Allogeneic hematopoietic stem cell transplantation (allo-SCT) is the sole curative therapy for myelodysplastic syndromes (MDS). However, whether bridging therapy (BRT) including azacitidine (AZA) and combination chemotherapy (CCT) prior to allo-SCT should be performed is unclear. We analyzed BRT and the outcomes of patients with myelodysplastic syndrome with excess blasts (MDS-EB) who were registered in a prospective observational study in order to clarify the optimal allo-SCT strategy for high-risk MDS. A total of 371 patients were included in this study. Among 188 patients (50.7%) who were considered for allo-SCT, 141 actually underwent allo-SCT. Among the patients who underwent allo-SCT, 64 received AZA, 29 received CCT and 26 underwent allo-SCT without BRT as an initial treatment. The multivariate analysis identified BRT as independent factors influencing overall survival (AZA vs. without BRT, hazard ratio [HR] 3.33, 95% confidence interval [95%CI] 1.44–7.70, P = 0.005; CCT vs. without BRT, HR 3.82, 95%CI 1.60–9.14, P = 0.003). In a multivariate analysis, BRT showed an independent association with progression-free survival (AZA vs. without BRT, HR 2.23, 95%CI 1.03–4.83, P = 0.041; CCT vs. without BRT, HR 2.94, 95%CI 1.29–6.69, P = 0.010). Transplant-eligible patients with MDS-EB should undergo upfront allo-SCT without BRT.

From a young age, a 63-year-old Japanese man had experienced difficulties with hemostasis during tooth extraction and epistaxis and swelling of bruised areas. He had previously been diagnosed with mild hemophilia (FVIII:C 8.5%) at age of 60 due to swelling of a right hip bruise and was administered FVIII concentrate for the first time. He had frequent bleeding around his shoulder joints and was given FVIII concentrates every time, but his hemostasis was poor. He was referred to our hospital because his FVIII activity decreased to1% and a low-titer inhibitor (2.0 BU/ml) was detected. Because of a shoulder hematoma and new subcutaneous bleeding on both forearms, recombinant FVIIa was used to perform the hemostatic treatment. Following hemostasis, emicizumab was administered subcutaneously every 2 weeks at a dose of 3.0 mg/kg. Approximately 2 months after starting emicizumab, inhibitors were no longer detected, and FVIII activity increased to 8% after 9 months. We encountered a case of mild hemophilia A with an inhibitor that was first diagnosed in old age. The incidence of inhibitors in non-severe hemophilia A is about 10%, and about 70% of those resolves spontaneously. In this case, suppression of bleeding by emicizumab may have contributed to the spontaneous disappearance of the inhibitor.

Bone marrow necrosis (BMN) occurs most frequently in hematological malignancies and sometimes in non-hematological disorders. Lymphoid diseases causing necrosis are regarded as high-grade disease. B-lymphoblastic leukemia/lymphoma is the most common malignant cause of BMN. Here, we present two patients with follicular lymphoma (FL) and MYC gene abnormalities who developed BMN. In one case of BMN, the necrosis disappeared in response to chemotherapy, and the patient survived with complete remission. In the other case, BMN remained even after chemotherapy, and effective chemotherapy could not be administered due to suppressed hematopoiesis, which led to the lymphoma worsening and the patient's death. Indolent lymphomas, such as FL, as in these cases, have the potential to develop BMN. It is important to detect the development of BMN and administer chemotherapy early to improve patient prognosis, since severe BMN prevents patients from receiving effective treatment.

Multiple myeloma (MM) is an incurable hematological malignancy. Despite the introduction of several novel drugs, most patients relapse. Biomarkers to identify the early signs of relapse will make it possible to adjust the therapeutic strategy before the disease worsens. Although understanding genetic changes is important for the treatment of MM, currently known biomarkers of relapse, including serum free-light chains and monoclonal paraproteins, are not associated with genetic changes. We therefore performed a multicenter study to examine the usefulness of circulating cell-free DNA (cfDNA) present in the peripheral blood (PB) plasma of patients as a biomarker for MM relapse. We identified several driver mutations by combined analysis of next-generation sequencing and existing databases of candidate oncogenes. Furthermore, relapse was detected more sensitively by monitoring the circulating cfDNA with these driver mutations than by conventional serum free-light chain examination. These results suggest the potential utility of cfDNA in the PB plasma of patients as a relevant early biomarker for MM relapse.

Cellular senescence refers to a pause in the cell cycle, usually in response to internal and/or external stress, including telomere dysfunction, abnormal cellular growth, and DNA damage. Several chemotherapeutic drugs, such as melphalan (MEL) and doxorubicin (DXR), induce cellular senescence in cancer cells. However, it is not clear whether these drugs induce senescence in immune cells. We evaluated the induction of cellular senescence in T cells were derived from human peripheral blood mononuclear cells (PBMNCs) in healthy donors using sub-lethal doses of chemotherapeutic agents. The PBMNCs were kept overnight in RPMI 1640 medium with 2% phytohemagglutinin and 10% fetal bovine serum and then cultured in RPMI 1640 with 20 ng/mL IL-2 and sub-lethal doses of chemotherapeutic drugs (2 µM MEL and 50 nM DXR) for 48 h. Sub-lethal doses of chemotherapeutic agents induced phenotypes associated with senescence, such as the formation of γH2AX nuclear foci, cell proliferation arrest, and induction of senescence-associated beta-galactosidase (SA-β-Gal) activity, (control vs. MEL, DXR; median mean fluorescence intensity (MFI) 1883 (1130–2163) vs. 2233 (1385–2254), 2406.5 (1377–3119), respectively) in T cells. IL6 and SPP1 mRNA, which are senescence-associated secretory phenotype (SASP) factors, were significantly upregulated by sublethal doses of MEL and DXR compared to the control (P = 0.043 and 0.018, respectively). Moreover, sub-lethal doses of chemotherapeutic agents significantly enhanced the expression of programmed death 1 (PD-1) on CD3 + CD4 + and CD3 + CD8 + T cells compared to the control (CD4 + T cells; P = 0.043, 0.043, and 0.043, respectively, CD8 + T cells; P = 0.043, 0.043, and 0.043, respectively). Our results suggest that sub-lethal doses of chemotherapeutic agents induce senescence in T cells and tumor immunosuppression by upregulating PD-1 expression on T cells.

Multiple myeloma (MM) is still extremely difficult to cure, and new therapeutic drugs are needed. We recently found that integrin β7 is constitutively activated in MM cells, and chimeric antigen receptor (CAR) T cells targeting activated integrin β7 have a significant anti-MM effect. In this study, we performed flow cytometry analysis of the expression of activated integrin β7 in bone marrow cells from 137 symptomatic MM patients. In 60/137 (44%) MM patients, activated integrin β7 was detected in most MM cells (> 80% of MM cells were in the positive gate). Activated integrin β7 was highly expressed in MM cells even in heavily treated patients. It also showed high expression in many CD38lo/−CD138−CD19+B cells, which reportedly include clonotypic B cells, in the bone marrow of MM patients. Taken together, these results suggest that CAR T-cell therapy targeting activated integrin β7 has the potential to benefit many patients with relapsed or refractory MM.

Background: Airway stenting is a useful form of palliation for patients with airway stenosis/fistulas; the stent can be removed after addressing the cause of the airway disorder. Patients with airway stents often complain of coughing and difficulty with expectoration, so the use of such stents can negatively affect pulmonary function and worsen symptoms. Objectives: The aim of this study was to compare pulmonary function and respiratory symptoms before and after stent removal. Methods: Patients who would later undergo simple airway stent removal were prospectively recruited in two institutions. All stents were removed using both rigid and flexible bronchoscopes with patients under general anesthesia. Pulmonary function tests were performed before stent removal and at 1 and 4 weeks after stent removal. All patients self-reported their respiratory symptoms using a 100-mm visual analog scale (VAS). Results: Of the 31 patients enrolled, 28 (23 with malignant stenoses, 3 with benign stenoses, and 2 with fistulas [21 silicone and 7 metallic stents]) were included in analyses. Pulmonary function measurements before stent removal and at 1 and 4 weeks after stent removal were as follows: vital capacity, 3.00, 3.04, and 3.08 L (p = 0.387); forced expiratory volume in 1 s, 1.96, 1.96, and 2.12 L (p = 0.034); and peak expiratory flow, 3.60, 4.28, and 5.06 L/s, respectively (p < 0.001). Symptoms (cough, sputum production, difficulty with expectoration, and dyspnea) evaluated using the VAS improved significantly after stent removal. No complications were encountered during removal. Conclusion: Removal of unnecessary airway stents improves pulmonary function and respiratory symptoms. Any stent that is no longer functioning should be removed.

Transactive response DNA-binding protein 43 kDa (TDP-43) encoded by the TARDBP gene is an evolutionarily conserved heterogeneous nuclear ribonucleoprotein (hnRNP) that regulates multiple steps of RNA metabolism, and its cytoplasmic aggregation characterizes degenerating motor neurons in amyotrophic lateral sclerosis (ALS). In most ALS cases, cytoplasmic TDP-43 aggregation occurs in the absence of mutations in the coding sequence of TARDBP. Thus, a major challenge in ALS research is to understand the nature of pathological changes occurring in wild-type TDP-43 and to explore upstream events in intracellular and extracellular milieu that promote the pathological transition of TDP-43. Despite the inherent obstacles to analyzing TDP-43 dynamics in in vivo motor neurons due to their anatomical complexity and inaccessibility, recent studies using cellular and animal models have provided important mechanistic insights into potential links between TDP-43 and motor neuron vulnerability in ALS. This review is intended to provide an overview of the current literature on the function and regulation of TDP-43-containing RNP granules or membraneless organelles, as revealed by various models, and to discuss the potential mechanisms by which TDP-43 can cause selective vulnerability of motor neurons in ALS.