Dysregulation of the progranulin-driven autophagy-lysosomal pathway mediates secretion of the nuclear protein TDP-43.

The cytoplasmic accumulation of the nuclear protein transactive response DNA-binding protein 43 kDa (TDP-43) has been linked to the progression of amyotrophic lateral sclerosis and frontotemporal lobar degeneration. TDP-43 secreted into the extracellular space has been suggested to contribute to the cell-to-cell spread of the cytoplasmic accumulation of TDP-43 throughout the brain; however, the underlying mechanisms remain unknown. We herein demonstrated that the secretion of TDP-43 was stimulated by the inhibition of the autophagy-lysosomal pathway driven by progranulin (PGRN), a causal protein of frontotemporal lobar degeneration. Among modulators of autophagy, only vacuolar-ATPase inhibitors, such as bafilomycin A1 (Baf), increased the levels of the full-length and cleaved forms of TDP-43 and the autophagosome marker LC3-II (microtubule-associated proteins 1A/1B light chain 3B) in extracellular vesicle fractions prepared from the culture media of HeLa, SH-SY5Y, or NSC-34 cells, whereas vacuolin-1, MG132, chloroquine, rapamycin, and serum starvation did not. The C-terminal fragment of TDP-43 was required for Baf-induced TDP-43 secretion. The Baf treatment induced the translocation of the aggregate-prone GFP-tagged C-terminal fragment of TDP-43 and mCherry-tagged LC3 to the plasma membrane. The Baf-induced secretion of TDP-43 was attenuated in autophagy-deficient ATG16L1 knockout HeLa cells. The knockdown of PGRN induced the secretion of cleaved TDP-43 in an autophagy-dependent manner in HeLa cells. The KO of PGRN in mouse embryonic fibroblasts increased the secretion of the cleaved forms of TDP-43 and LC3-II. The treatment inducing TDP-43 secretion increased the nuclear translocation of GFP-tagged transcription factor EB, a master regulator of the autophagy-lysosomal pathway in SH-SY5Y cells. These results suggest that the secretion of TDP-43 is promoted by dysregulation of the PGRN-driven autophagy-lysosomal pathway.

Mechanical Linkage between Achilles Tendon and Plantar Fascia Accounts for Range of Motion of Human Ankle-Foot Complex.

PURPOSE: The human ankle-foot complex possesses a passive range of motion (ROM) through changes in tibiocalcaneal ( θcal ) and foot arch ( θarch ) angles. Based on the anatomical linkage between the Achilles tendon (AT) and plantar fascia (PF), we hypothesized that AT and PF with different mechanical properties conjointly modulate the passive ROM of the human ankle-foot complex. We examined the association of AT and PF stiffness with passive ankle-foot ROM and further addressed differences between sexes. METHODS: A series of sagittal magnetic resonance images of the foot and passive ankle plantar flexion torque were obtained for 20 men and 20 women with their ankle-foot passively rotated from 30° of plantar flexion to 20° of dorsiflexion. Based on the measured changes in AT and PF lengths, θcal , θarch , and passive torque, AT and PF stiffness were determined. RESULTS: Upon passive ankle dorsiflexion, AT and PF were lengthened; their length changes were inversely correlated. Men showed a stiffer AT, more compliant PF, less calcaneal rotation, and greater foot arch deformation compared with women. Furthermore, we found inverse correlations between AT stiffness and ROM of θcal , and between PF stiffness and ROM of θarch in men and women. CONCLUSIONS: Passive AT and PF extensibility counter each other. AT and PF stiffness and passive ROM of ankle-foot components were countered between sexes; however, associations between stiffness and passive ROM of the ankle-foot complex were consistent between sexes. Our findings support the notion that the balanced mechanical interaction between the AT and PF can account for the passive ROM of the human ankle-foot complex in vivo , and the differences between sexes.

Efficacy of neoadjuvant chemotherapy for initially resectable colorectal liver metastases: A retrospective cohort study.

BACKGROUND: The liver is the most common metastatic site of colorectal cancer. Hepatectomy is the mainstay of treatment for patients with colorectal liver metastases (CRLMs). However, there are cases of early recurrence after upfront hepatectomy alone. In selected high-risk patients, neoadjuvant chemotherapy (NAC) may improve long-term survival. AIM: To determine the efficacy of NAC for initially resectable CRLMs. METHODS: Among 644 patients who underwent their first hepatectomy for CRLMs at our institution, 297 resectable cases were stratified into an upfront hepatectomy group (238 patients) and a NAC group (59 patients). Poor prognostic factors for upfront hepatectomy were identified using multivariate logistic regression analysis. Propensity score matching was used to compare clinical outcomes between the upfront hepatectomy and NAC groups, according to the number of poor prognostic factors. Survival curves were estimated using the Kaplan-Meier method and compared using the log-rank test. RESULTS: Preoperative carcinoembryonic antigen levels (≥ 10 ng/mL) (P = 0.003), primary histological type (other than well/moderately differentiated) (P = 0.04), and primary lymph node metastases (≥ 1) (P = 0.04) were identified as independent poor prognostic factors for overall survival (OS) in the upfront hepatectomy group. High-risk status was defined as the presence of two or more risk factors. After propensity score matching, 50 patients were matched in each group. Among high-risk patients, the 5-year OS rate was significantly higher in the NAC group (13 patients) than in the upfront hepatectomy group (18 patients) (100% vs 34%; P = 0.02). CONCLUSION: NAC may improve the prognosis of high-risk patients with resectable CRLMs who have two or more risk factors.

Overexpression of progranulin increases pathological protein accumulation by suppressing autophagic flux.

Progranulin (PGRN) haploinsufficiency from autosomal dominant mutations in the PGRN gene causes frontotemporal lobar degeneration, which is characterized by cytoplasmic inclusions predominantly containing TDP-43 (FTLD-TDP). PGRN supplementation for patients with a PGRN gene mutation has recently been proposed as a therapeutic strategy to suppress FTLD-TDP. However, it currently remains unclear whether excessive amounts of PGRN are beneficial or harmful. We herein report the effects of PGRN overexpression on autophagic flux in a cultured cell model. PGRN overexpression increased the level of an autophagosome marker without promoting autophagosome formation and decreased the signal intensity of an autolysosome marker, indicating the suppression of autophagic flux due to reductions in the formation of autolysosomes. Assessments of lysosome numbers and biogenesis using LysoTracker and cells stably expressing TFEB-GFP, respectively, indicated that PGRN overexpression increased the lysosome numbers without lysosomal biogenesis. These results suggest that PGRN overexpression suppressed autophagic flux by inhibiting autophagosome-lysosome fusion. Moreover, PGRN overexpression enhanced polyglutamine aggregation and aggregate-prone TDP-43 accumulation, indicating that the suppression of autophagic flux by excessive amounts of PGRN worsens the pathology of neurodegenerative diseases.

Impact of intramuscular adipose tissue content on short- and long-term outcomes of hepatectomy for colorectal liver metastasis: a retrospective analysis.

BACKGROUND: Numerous reports regarding sarcopenia have focused on the quantity of skeletal muscle. In contrast, the impact of the quality of skeletal muscle has not been well investigated. METHODS: A retrospective analysis of 115 patients who underwent initial hepatectomy for colorectal liver metastasis between January 2009 and December 2016 in our hospital was performed. Intramuscular adipose tissue content (IMAC) was used to evaluate the quality of skeletal muscle by analysing computed tomography (CT) images at the level of the umbilicus. The impact of poor skeletal muscle quality on short-term and long-term outcomes after hepatectomy for colorectal liver metastasis was analysed. RESULTS: Patients were divided into two groups (high IMAC and normal IMAC) according to their IMAC values, and their backgrounds were compared. There were no significant differences in most factors between the two groups. However, both body mass index (P = 0.030) and the incidence of postoperative complications of Clavien-Dindo grade 3 or worse (P = 0.008) were significantly higher in the high-IMAC group. In multivariate analyses, an operative blood loss > 600 ml (P = 0.006) and high IMAC (P = 0.008) were associated with postoperative complications of Clavien-Dindo grade 3 or worse. Overall survival and recurrence-free survival were significantly lower (P < 0.001 and P = 0.045, respectively) in the high-IMAC group than in the normal IMAC group. In multivariate analyses for poor overall survival, high IMAC was associated with poor overall survival (P < 0.001). CONCLUSIONS: IMAC is a prognostic factor for poor short- and long-term outcomes in patients with colorectal liver metastasis.

Functional domains of the FSHD-associated DUX4 protein.

Aberrant expression of the full-length isoform of DUX4 (DUX4-FL) appears to underlie pathogenesis in facioscapulohumeral muscular dystrophy (FSHD). DUX4-FL is a transcription factor and ectopic expression of DUX4-FL is toxic to most cells. Previous studies showed that DUX4-FL-induced pathology requires intact homeodomains and that transcriptional activation required the C-terminal region. In this study, we further examined the functional domains of DUX4 by generating mutant, deletion, and fusion variants of DUX4. We compared each construct to DUX4-FL for (i) activation of a DUX4 promoter reporter, (ii) expression of the DUX4-FL target gene ZSCAN4, (iii) effect on cell viability, (iv) activation of endogenous caspases, and (v) level of protein ubiquitination. Each construct produced a similarly sized effect (or lack of effect) in each assay. Thus, the ability to activate transcription determined the extent of change in multiple molecular and cellular properties that may be relevant to FSHD pathology. Transcriptional activity was mediated by the C-terminal 80 amino acids of DUX4-FL, with most activity located in the C-terminal 20 amino acids. We also found that non-toxic constructs with both homeodomains intact could act as inhibitors of DUX4-FL transcriptional activation, likely due to competition for promoter sites.This article has an associated First Person interview with the first author of the paper.

PML-RARα and its phosphorylation regulate pml oligomerization and HIPK2 stability.

The PML gene is frequently fused to the retinoic acid receptor α (RARα) gene in acute promyelocytic leukemia (APL), generating a characteristic PML-RARα oncogenic chimera. PML-RARα disrupts the discrete nuclear speckles termed nuclear bodies, which are formed in PML, suggesting that nuclear body disruption is involved in leukemogenesis. Nuclear body formation that relies upon PML oligomerization and its stabilization of the hypoxia-inducible protein kinase (HIPK)-2 is disrupted by expression of the PML-RARα chimera. Here, we report that disruption of nuclear bodies is also mediated by PML-RARα inhibition of PML oligomerization. PKA-mediated phosphorylation of PML-RARα blocked its ability to inhibit PML oligomerization and destabilize HIPK2. Our results establish that both PML oligomerization and HIPK2 stabilization at nuclear bodies are important for APL cell differentiation, offering insights into the basis for the most common prodifferentiation therapies of APL used clinically.

[A case of consciousness disorder induced by the syndrome of inappropriate secretion of antidiuretic hormone following cisplatin and 5-fluorouracil chemotherapy in a patient with esophageal cancer].

We report a case of consciousness disorder following the fourth course of chemotherapy with cisplatin (CDDP) and 5- fluorouracil (5-FU) in a patient with esophageal cancer. A 74-year-old man was admitted to our hospital to receive chemotherapy for esophageal cancer. Six days after chemotherapy, the patient showed impaired consciousness and his serum sodium concentration was found to be 125 mEq/L, but no edema or dehydration was noted. This hyponatremic state was diagnosed as CDDP-induced syndrome of inappropriate secretion of antidiuretic hormone (SIADH) on the basis of serum and urine hypo-osmolality. Accordingly, fluid intake was restricted and sodium supplements were administered, resulting in an appropriate increase in the serum sodium concentration to 132 mEq/L in 4 days.