LYSMD proteins promote activation of Rab32-family GTPases for lysosome-related organelle biogenesis.

Lysosome-related organelles (LROs) are specialized lysosomes with cell type-specific roles in organismal homeostasis. Dysregulation of LROs leads to many human disorders, but the mechanisms underlying their biogenesis are not fully understood. Here, we identify a group of LYSMD proteins as evolutionarily conserved regulators of LROs. In Caenorhabditis elegans, mutations of LMD-2, a LysM domain-containing protein, reduce the levels of the Rab32 GTPase ortholog GLO-1 on intestine-specific LROs, the gut granules, leading to their abnormal enlargement and defective biogenesis. LMD-2 interacts with GLO-3, a subunit of GLO-1 guanine nucleotide exchange factor (GEF), thereby promoting GLO-1 activation. Mammalian homologs of LMD-2, LYSMD1, and LYSMD2 can functionally replace LMD-2 in C. elegans. In mammals, LYSMD1/2 physically interact with the HPS1 subunit of BLOC-3, the GEF of Rab32/38, thus promoting Rab32 activation. Inactivation of both LYSMD1 and LYSMD2 reduces Rab32 activation, causing melanosome enlargement and decreased melanin production in mouse melanoma cells. These findings provide important mechanistic insights into LRO biogenesis and functions.

Structural insights into the molecular effects of the anthelmintics monepantel and betaine on the Caenorhabditis elegans acetylcholine receptor ACR-23.

Anthelmintics are drugs used for controlling pathogenic helminths in animals and plants. The natural compound betaine and the recently developed synthetic compound monepantel are both anthelmintics that target the acetylcholine receptor ACR-23 and its homologs in nematodes. Here, we present cryo-electron microscopy structures of ACR-23 in apo, betaine-bound, and betaine- and monepantel-bound states. We show that ACR-23 forms a homo-pentameric channel, similar to some other pentameric ligand-gated ion channels (pLGICs). While betaine molecules are bound to the classical neurotransmitter sites in the inter-subunit interfaces in the extracellular domain, monepantel molecules are bound to allosteric sites formed in the inter-subunit interfaces in the transmembrane domain of the receptor. Although the pore remains closed in betaine-bound state, monepantel binding results in an open channel by wedging into the cleft between the transmembrane domains of two neighboring subunits, which causes dilation of the ion conduction pore. By combining structural analyses with site-directed mutagenesis, electrophysiology and in vivo locomotion assays, we provide insights into the mechanism of action of the anthelmintics monepantel and betaine.

Exploring lysosomal biology: current approaches and methods.

Lysosomes are the degradation centers and signaling hubs in the cell. Lysosomes undergo adaptation to maintain cell homeostasis in response to a wide variety of cues. Dysfunction of lysosomes leads to aging and severe diseases including lysosomal storage diseases (LSDs), neurodegenerative disorders, and cancer. To understand the complexity of lysosome biology, many research approaches and tools have been developed to investigate lysosomal functions and regulatory mechanisms in diverse experimental systems. This review summarizes the current approaches and tools adopted for studying lysosomes, and aims to provide a methodological overview of lysosomal research and related fields.

Daphmacrimines A-K, Daphniphyllum alkaloids from Daphniphyllum macropodum Miq.

Daphmacrimines A-K (1-11) were isolated from the leaves and stems of Daphniphyllum macropodum Miq. Their structures and stereochemistries were determined by extensive techniques, including HRESIMS, NMR, ECD, IR, and single-crystal X-ray crystallography. Daphmacrimines A-D (1-4) are unprecedented Daphniphyllum alkaloids with a 2-oxazolidinone ring. Daphmacrimine I (9) contains a nitrile group, which is relatively rare in naturally occurring alkaloids. The abilities of daphmacrimines A-D and daphmacrimines G-K to enhance lysosomal biogenesis were evaluated through LysoTracker Red staining. Daphmacrimine K (11) can induce lysosomal biogenesis and promote autophagic flux.

The HEAT repeat protein HPO-27 is a lysosome fission factor.

Lysosomes are degradation and signalling centres crucial for homeostasis, development and ageing1. To meet diverse cellular demands, lysosomes remodel their morphology and function through constant fusion and fission2,3. Little is known about the molecular basis of fission. Here we identify HPO-27, a conserved HEAT repeat protein, as a lysosome scission factor in Caenorhabditis elegans. Loss of HPO-27 impairs lysosome fission and leads to an excessive tubular network that ultimately collapses. HPO-27 and its human homologue MROH1 are recruited to lysosomes by RAB-7 and enriched at scission sites. Super-resolution imaging, negative-staining electron microscopy and in vitro reconstitution assays reveal that HPO-27 and MROH1 self-assemble to mediate the constriction and scission of lysosomal tubules in worms and mammalian cells, respectively, and assemble to sever supported membrane tubes in vitro. Loss of HPO-27 affects lysosomal morphology, integrity and degradation activity, which impairs animal development and longevity. Thus, HPO-27 and MROH1 act as self-assembling scission factors to maintain lysosomal homeostasis and function.

Anatomic reconstruction of the lateral ligaments using allograft tendon and suspensory fixation for chronic lateral ankle instability with poor remnant quality: results and complications.

PURPOSE: Treatment of chronic lateral ankle instability (CLAI) with poor remnant quality is challenging. The aim of the present study was to evaluate clinical results and complications of anatomic reconstruction of the lateral ligaments using allograft tendon and suspensory fixation in the treatment of such patients. METHODS: One hundred and eight patients with CLAI, who were treated surgically using anatomic reconstruction with allograft tendon and suspensory fixation between April 2016 and January 2018 at our hospital, were retrospectively analysed. None of the patients had sufficient ligament remnants for the modified Broström procedure during the intraoperative evaluation. Eighteen patients were excluded. Seventeen patients were lost to follow-up and 73 patients completed the study. The mean duration of instability symptoms was 39.1 months (range, 6-480 months). The mean follow-up time was 57.5 months (range, 48-69 months). Clinical results were evaluated using the Karlsson scoring scale, American Orthopaedic Foot and Ankle Society-Ankle and Hindfoot (AOFAS-AH) score, visual analogue scale (VAS), patients' subjective satisfaction, and incidence of complications. Mechanical stability was evaluated using the varus talar tilt angle (TTA) and anterior talar displacement (ATD). RESULTS: The AOFAS-AH scores significantly improved from 67.7 ± 8.5 points to 89.8 ± 9.5 (p < 0.001). The Karlsson scoring scales evolved from 58.8 ± 16.5 to 88.4 ± 11.2 (p < 0.001). VAS scores significantly decreased from 2.9 ± 1.3 to 1.1 ± 1.0 (p < 0.001). On stress radiographs, TTA decreased from 15.1 ± 2.5 degrees to 5.8 ± 2.1 degrees (p < 0.001), whereas ATD reduced from 13.4 ± 2.9 mm to 5.7 ± 1.5 mm (p < 0.001). Patients' subjective satisfaction indicated 46 excellent, 20 good, 5 fair, and 2 bad results. Postoperatively, 15 cases (20.5%) did not achieve complete relief of discomfort or swelling, 9 cases (12.3%) experienced joint stiffness or decreased range of motion, and 6 cases (8.2%) had soft tissue irritation. Residual instability and reoperation are rare. Allograft rejection or wound infection was not observed. CONCLUSION: For the CLAI patients with poor remnant quality, anatomic reconstruction of the lateral ligaments using allograft tendon and suspensory fixation is an effective procedure, while the top three complications in incidence were residual discomfort, joint stiffness, and soft tissue irritation. LEVELS OF EVIDENCE: Level IV, retrospective case series.

Comparison of prone-supine versus supine position for the treatment of pilon fractures via modified posteromedial approach combined with anterolateral approach.

BACKGROUND: Most of modified posteromedial approaches require prone position for the treatment of pilon fractures. We describe the technique of modified posteromedial approach under supine position. The goal of the study was to compare the radiographic and clinical outcomes of prone-supine versus supine position for the treatment of pilon fractures via modified posteromedial approach combined with anterolateral approach. METHODS: A total of 50 retrospectively consecutive pilon fractures that underwent open reduction internal fixation via modified posteromedial approach combined with anterolateral approach from 2016 to 2019 were reviewed at least a two-year follow up. The positions of patients were divided into two groups: prone-supine versus supine position (26 vs 24, respectively). The operation time, radiographic outcomes including bone union time and ratio of congruent articular reduction were evaluated. The post-operative function was evaluated using the Manchester Oxford score (MOXFQ) and the visual analogue score (VAS). The motion of ankle joint and complications and were also compared. RESULTS: The mean follow-up was 42.2(24.7-73.0) months in the prone-supine group and 42.7(37.3-56.5) months in the supine group (P = .87). The mean operation time was 141.9 ± 10.1 min in the prone-supine group and 107.5 ± 18.9 min in the supine group (P = .00). There was no significant difference in the bone union time and ratio of congruent articular reduction between the two groups. There was no significant difference in the final MOXFQ score, VAS score, and the mean range of ankle motion between the two groups (P > .05). The total incidence of complications was 11.5% in the prone-supine group and 16.6% in the supine group (P = .66). CONCLUSION: The patient in the prone-supine position versus supine position for pilon fractures via modified posteromedial approach combined with anterolateral approach contributed comparable quality of reduction, bone union time functional outcomes and complications. The supine technique was significantly shorter in terms of operation time.

WDR91 specifies the endosomal retrieval subdomain for retromer-dependent recycling.

Retromer-dependent endosomal recycling of membrane receptors requires Rab7, sorting nexin (SNX)-retromer, and factors that regulate endosomal actin organization. It is not fully understood how these factors cooperate to form endosomal subdomains for cargo retrieval and recycling. Here, we report that WDR91, a Rab7 effector, is the key factor that specifies the endosomal retrieval subdomain. Loss of WDR91 causes defective recycling of both intracellular and cell surface receptors. WDR91 interacts with SNXs through their PX domain, and with VPS35, thus promoting their interaction with Rab7. WDR91 also interacts with the WASH subunit FAM21. In WDR91-deficient cells, Rab7, SNX-retromer, and FAM21 fail to localize to endosomal subdomains, and endosomal actin organization is impaired. Re-expression of WDR91 enables Rab7, SNX-retromer, and FAM21 to concentrate at WDR91-specific endosomal subdomains, where retromer-mediated membrane tubulation and release occur. Thus, WDR91 coordinates Rab7 with SNX-retromer and WASH to establish the endosomal retrieval subdomains required for retromer-mediated endosomal recycling.

Clinical and MRI Donor-Site Outcomes After Autograft Harvesting From the Medial Trochlea for Talar Osteochondral Lesions: Minimum 5-Year Clinical Follow-up.

Background: Autologous osteochondral transplantation (AOT) is a treatment option for large or cystic osteochondral lesions of the talus (OLTs), with promising clinical results. However, donor-site morbidity (DSM) has always been a concern with this procedure. Purpose: To investigate the clinical and radiological outcomes of autograft harvesting from the medial trochlea for OLTs. Study Design: Case series; Level of evidence, 4. Methods: A total of 46 consecutive patients were included after AOT procedures for OLTs, with donor autografts (single or double plugs) harvested from the medial trochlea of the ipsilateral knee. Lysholm scores were collected postoperatively at 12-month intervals to assess clinical outcomes. Postoperative magnetic resonance imaging (MRI) was used to assess the donor site using the MOCART (magnetic resonance observation of cartilage repair tissue) score. DSM was evaluated at 12-month intervals. Statistical analysis was performed to compare patients treated with single-plug and double-plug AOT procedures and establish whether there was any correlation between MOCART and Lysholm scores. Results: The mean follow-up period was 98.3 months (range, 67-144 months). The Lysholm scores for all patients were 92.5 ± 6.1 and 99.9 ± 0.2 at the 12-month and final follow-ups, respectively. MRI of the donor sites was taken at an average of 93.8 ± 20.5 (range, 61-141) months postoperatively, and the mean MOCART score was 76.2 ± 4.9. The overall incidence of DSM in this study was 4.3% at 12 months, postoperatively, which decreased to 0% at the 24-month follow-up. There was no significant difference in either the Lysholm score (P = .16) or the MOCART score (P = .83) between the single-plug and double-plug groups at the final follow-up. There were no significant correlations between MOCART and Lysholm scores and patient age, number of grafts, or body mass index. Conclusion: According to the study findings, the DSM of donor autografts harvested from the medial trochlea was low, and the number (single or double) of grafts did not affect the functional outcome.

Filamin FLN-2 promotes MVB biogenesis by mediating vesicle docking on the actin cytoskeleton.

Multivesicular bodies (MVBs) contain intralumenal vesicles that are delivered to lysosomes for degradation or released extracellularly for intercellular signaling. Here, we identified Caenorhabditis elegans filamin FLN-2 as a novel regulator of MVB biogenesis. FLN-2 co-localizes with V-ATPase subunits on MVBs, and the loss of FLN-2 affects MVB biogenesis, reducing the number of MVBs in C. elegans hypodermis. FLN-2 associates with actin filaments and is required for F-actin organization. Like fln-2(lf) mutation, inactivation of the V0 or V1 sector of V-ATPase or inhibition of actin polymerization impairs MVB biogenesis. Super-resolution imaging shows that FLN-2 docks V-ATPase-decorated MVBs onto actin filaments. FLN-2 interacts via its calponin-homology domains with F-actin and the V1-E subunit, VHA-8. Our data suggest that FLN-2 mediates the docking of MVBs on the actin cytoskeleton, which is required for MVB biogenesis.

Therapeutic efficacy analysis of distal tibia varus syndrome with different classification and different therapy: a cross-sectional study.

Background: We often attribute the lateral ankle impingement to the valgus calcaneus, while ignoring the varus distal tibia. The diagnostic criteria, severity and treatment of distal tibia varus syndrome (DTVS) have not been reported. This retrospective study sought to propose a diagnosis and classification system for DTVS based on patients' clinical symptoms and imaging findings. Methods: A total of 76 symptomatic patients with varus distal tibia and congruent ankle examined between 2010 and 2018 were involved to evaluate clinically based on their SF-36 scores, AOFAS ankle-hindfoot scores, and VAS scores. Each patient's history, symptoms, and MRI images were analyzed retrospectively, and their weight-bearing ankle radiographs were observed to measure the tibial anterior surface angle (TAS) and tibial tilt angle (TTA). Paired t-test and Kruskal-Wallis test were used to compare the results above. Results: Forty-three men and 33 women with an average age of 46 years (range, 28-68 years) included. Besides the same symptom of intermittent subfibular pain, 3 types of DTVS were defined: (I) Type I: a sloped surface of the distal tibia with the congruent tibiotalar joint on radiographs; (II) Type II: a sloped surface of the distal tibia with the congruent tibiotalar joint on radiographs, and soft-tissue edema inferior to the lateral malleolus on MRI images; and (III) Type III: the same symptoms as Type II, plus osteochondral lesions of the talus on MRI images. Under our proposed classification system, 26 patients were classified as Type I, requiring conservative treatment, 22 as Type II, and 28 as Type III under supramalleolar valgus osteotomy. The ankle functional evaluation scores, such as the SF-36 (74.14±12.50 preoperatively and 85.22±8.83 postoperatively), AOFAS (71.14±15.19 preoperatively and 87.53±8.62 postoperatively), and VAS (5.41±1.10 preoperatively and 1.82±1.08 postoperatively) scores for all types were significantly improved (P<0.01). The TAS (80.38°±4.80° preoperatively and 90.44°±3.96° postoperatively) and TTA (13.02°±3.41° preoperatively and 0.62°±2.67° postoperatively) of all the patients on the weight-bearing ankle radiographs were significantly improved (P<0.01). Conclusions: DTVS, causing lateral ankle impingement, can be diagnosed based on clinical manifestations and imaging findings. Our classification system can aid in the decision-making process in relation to the appropriate form of conservative or surgical treatments.

A feedback loop engaging propionate catabolism intermediates controls mitochondrial morphology.

D-2-Hydroxyglutarate (D-2HG) is an α-ketoglutarate-derived mitochondrial metabolite that causes D-2-hydroxyglutaric aciduria, a devastating developmental disorder. How D-2HG adversely affects mitochondria is largely unknown. Here, we report that in Caenorhabditis elegans, loss of the D-2HG dehydrogenase DHGD-1 causes D-2HG accumulation and mitochondrial damage. The excess D-2HG leads to a build-up of 3-hydroxypropionate (3-HP), a toxic metabolite in mitochondrial propionate oxidation, by inhibiting the 3-HP dehydrogenase HPHD-1. We demonstrate that 3-HP binds the MICOS subunit MIC60 (encoded by immt-1) and inhibits its membrane-binding and membrane-shaping activities. We further reveal that dietary and gut bacteria affect mitochondrial health by modulating the host production of 3-HP. These findings identify a feedback loop that links the toxic effects of D-2HG and 3-HP on mitochondria, thus providing important mechanistic insights into human diseases related to D-2HG and 3-HP.

The Metabolite Saccharopine Impairs Neuronal Development by Inhibiting the Neurotrophic Function of Glucose-6-Phosphate Isomerase.

Mutations in the Aminoadipate-Semialdehyde Synthase (AASS) gene encoding α-aminoadipic semialdehyde synthase lead to hyperlysinemia-I, a benign metabolic variant without clinical significance, and hyperlysinemia-II with developmental delay and intellectual disability. Although both forms of hyperlysinemia display biochemical phenotypes of questionable clinical significance, an association between neurologic disorder and a pronounced biochemical abnormality remains a challenging clinical question. Here, we report that Aass mutant male and female mice carrying the R65Q mutation in α-ketoglutarate reductase (LKR) domain have an elevated cerebral lysine level and a normal brain development, whereas the Aass mutant mice carrying the G489E mutation in saccharopine dehydrogenase (SDH) domain exhibit elevations of both cerebral lysine and saccharopine levels and a smaller brain with defective neuronal development. Mechanistically, the accumulated saccharopine, but not lysine, leads to impaired neuronal development by inhibiting the neurotrophic effect of glucose-6-phosphate isomerase (GPI). While extracellular supplementation of GPI restores defective neuronal development caused by G498E mutation in SDH of Aass. Altogether, our findings not only unravel the requirement for saccharopine degradation in neuronal development, but also provide the mechanistic insights for understanding the neurometabolic disorder of hyperlysinemia-II.SIGNIFICANCE STATEMENT The association between neurologic disorder and a pronounced biochemical abnormality in hyperlysinemia remains a challenging clinical question. Here, we report that mice carrying the R65Q mutation in lysine α-ketoglutarate reductase (LKR) domain of aminoadipate-semialdehyde synthase (AASS) have an elevated cerebral lysine levels and a normal brain development, whereas those carrying the G489E mutation in saccharopine dehydrogenase (SDH) domain of AASS exhibit an elevation of both cerebral lysine and saccharopine and a small brain with defective neuronal development. Furthermore, saccharopine impairs neuronal development by inhibiting the neurotrophic effect of glucose-6-phosphate isomerase (GPI). These findings demonstrate saccharopine degradation is essential for neuronal development.

A pair of transporters controls mitochondrial Zn2+ levels to maintain mitochondrial homeostasis.

Zn2+ is required for the activity of many mitochondrial proteins, which regulate mitochondrial dynamics, apoptosis and mitophagy. However, it is not understood how the proper mitochondrial Zn2+ level is achieved to maintain mitochondrial homeostasis. Using Caenorhabditis elegans, we reveal here that a pair of mitochondrion-localized transporters controls the mitochondrial level of Zn2+. We demonstrate that SLC-30A9/ZnT9 is a mitochondrial Zn2+ exporter. Loss of SLC-30A9 leads to mitochondrial Zn2+ accumulation, which damages mitochondria, impairs animal development and shortens the life span. We further identify SLC-25A25/SCaMC-2 as an important regulator of mitochondrial Zn2+ import. Loss of SLC-25A25 suppresses the abnormal mitochondrial Zn2+ accumulation and defective mitochondrial structure and functions caused by loss of SLC-30A9. Moreover, we reveal that the endoplasmic reticulum contains the Zn2+ pool from which mitochondrial Zn2+ is imported. These findings establish the molecular basis for controlling the correct mitochondrial Zn2+ levels for normal mitochondrial structure and functions.

Loss of RNA-Binding Protein HuR Leads to Defective Ependymal Cells and Hydrocephalus.

Multiciliated ependymal cells line the ventricle wall and generate CSF flow through ciliary beating. Defects in ependymal cells cause hydrocephalus; however, there are still significant gaps in our understanding the molecular, cellular and developmental mechanisms involved in the pathogenesis of hydrocephalus. Here, we demonstrate that specific deletion of RNA-binding protein (RBP) Hu antigen R (HuR) in the mouse brain results in hydrocephalus and causes postnatal death. HuR deficiency leads to impaired ependymal cell development with defective motile ciliogenesis in both female and male mice. Transcriptome-wide analysis reveals that HuR binds to mRNA transcripts related to ciliogenesis, including cilia and flagella associated protein 52 (Cfap52), the effector gene of Foxj-1 and Rfx transcriptional factors. HuR deficiency accelerates the degradation of Cfap52 mRNA, while overexpression of Cfap52 is able to promote the development of HuR-deficient ependymal cells. Taken together, our results unravel the important role of HuR in posttranscriptional regulation of ependymal cell development by stabilizing Cfap52 mRNA.SIGNIFICANCE STATEMENT This study identifies Hu antigen R (HuR) as a genetic factor involved in the pathogenesis of hydrocephalus. Mechanistically, HuR regulates ependymal cell differentiation and ciliogenesis through stabilizing Cfap52 mRNA, the effector gene of Foxj-1 and Rfx transcriptional factors.

M05B5.4 (lysosomal phospholipase A2) promotes disintegration of autophagic vesicles to maintain C. elegans development.

The autophagosome has two lipid bilayer membranes. The outer membrane fuses with the lysosome, while the inner membrane is degraded to release autophagic contents for degradation. It remains unclear how the inner vesicle of the autophagosome (called the autophagic vesicle) is disintegrated after autophagosome-lysosome fusion. Here, we identified C. elegans LPLA-2/M05B5.4 as a key enzyme that degrades membranous material in lysosomes. LPLA-2 is homologous to human PLA2G15, a lysosomal phospholipase A2 family protein that catalyzes cleavage of membrane phospholipids. We found that loss of LPLA-2 causes accumulation of large membrane whor ls in enlarged lysosomes and both phenotypes are suppressed by blocking macroautophagy/autophagy. Moreover, autophagic vesicles persisted in enlarged lysosomes in PLA2G15 knockdown cells and lpla-2(lf) mutants, which suggests that the breakdown of the inner autophagosomal membrane in lysosomes is impaired. lpla-2(lf) mutants exhibit severe defects in both embryonic and larval development. Our data suggest that disintegration of the inner autophagosomal membrane by LPLA-2 promotes the release and subsequent degradation of autophagic contents in lysosomes, which is essential for C. elegans development.Abbreviations: ATG: autophagy related; EPG: ectopic PGL granules; GFP: green fluorescent protein; LGG-1: LC3, GABARAP and GATE-16 family; LPLA-2: lysosomal phospholipase A2; PGL: P granule abnormality protein; PLA2: phospholipase A2; SD: standard deviation; SEPA-1: suppressor of ectopic P granules in autophagy mutant; SQST-1: sequestosome related.

Staged surgical management of sinus tarsi syndrome: our experience of 273 cases.

BACKGROUND: The sinus tarsi syndrome (STS) is a common foot and ankle disease with controversial pathogenesis and treatment procedures. This long-term study aimed to analyze the effect of a staged surgical strategy for STS. METHODS: Clinical data were retrospectively analyzed in 273 STS patients [129 men and 144 women; mean age: 36 years (10-60 years)] treated between 2006 and 2016. The 89 patients underwent different surgeries, including sinus tarsal debridement, subtalar joint stabilization, sinus tarsal denervation, tarsal coalition resection, or subtalar arthrodesis. The patients' American Orthopedic Foot & Ankle Society (AOFAS) ankle-hindfoot scores, visual analogue scale (VAS) scores for pain during daily activities, and 36-item short-form health survey (SF-36) scores at the first visit and latest follow-up were assessed by paired T-test. RESULTS: The 89 patients who failed conservative treatments first underwent tarsal sinus soft tissue debridement, with 52 patients remaining in remission after 2 years. The other 37 patients with relapse underwent further surgeries. Five of the 19 patients with subtalar instability were cured following ligament reconstruction surgery. Two of the four patients with severe neurological signs recovered after nerve release surgery. Five of the 10 patients with tarsal coalition were cured by resection of the talocalcaneal bridge. A total of 21 patients failed their second operations due to peroneal spasm, and were eventually successfully treated by subtalar arthrodesis. In addition, subtalar arthrodesis was directly performed in the remaining four patients with peroneal spastic flatfoot. After the final operations, all patients achieved satisfactory results. The AOFAS ankle-hindfoot scores increased from 34.83±12.21 preoperatively to 85.52±7.07 postoperatively (t=-24.62, P<0.01), the VAS scores decreased from 8.14±1.52 to 2.14±1.00 (t=24.65, P<0.01), and the SF-36 scores increased from 36.58±11.36 to 86.22±9.17 (t=-28.13, P<0.01). CONCLUSIONS: In this study, we observed that 67% (184/273) of patients with STS need a staged surgical management. According to the etiology, symptoms, and severity, soft tissue surgery is the first choice. However, simple soft tissue surgeries may fail to achieve long-term results. Once the symptoms recur and become difficult to cure, the staged surgical strategy for STS we proposed can be the best choice to achieve long-term results.

Lysosome biogenesis: Regulation and functions.

Lysosomes are degradation centers and signaling hubs in cells and play important roles in cellular homeostasis, development, and aging. Changes in lysosome function are essential to support cellular adaptation to multiple signals and stimuli. Therefore, lysosome biogenesis and activity are regulated by a wide variety of intra- and extracellular cues. Here, we summarize current knowledge of the regulatory mechanisms of lysosome biogenesis, including synthesis of lysosomal proteins and their delivery via the endosome-lysosome pathway, reformation of lysosomes from degradative vesicles, and transcriptional regulation of lysosomal genes. We survey the regulation of lysosome biogenesis in response to nutrient and nonnutrient signals, the cell cycle, stem cell quiescence, and cell fate determination. Finally, we discuss lysosome biogenesis and functions in the context of organismal development and aging.

The Rab7 effector WDR91 promotes autophagy-lysosome degradation in neurons by regulating lysosome fusion.

The effectors of the Rab7 small GTPase play multiple roles in Rab7-dependent endosome-lysosome and autophagy-lysosome pathways. However, it is largely unknown how distinct Rab7 effectors coordinate to maintain the homeostasis of late endosomes and lysosomes to ensure appropriate endolysosomal and autolysosomal degradation. Here we report that WDR91, a Rab7 effector required for early-to-late endosome conversion, is essential for lysosome function and homeostasis. Mice lacking Wdr91 specifically in the central nervous system exhibited behavioral defects and marked neuronal loss in the cerebral and cerebellar cortices. At the cellular level, WDR91 deficiency causes PtdIns3P-independent enlargement and dysfunction of lysosomes, leading to accumulation of autophagic cargoes in mouse neurons. WDR91 competes with the VPS41 subunit of the HOPS complex, another Rab7 effector, for binding to Rab7, thereby facilitating Rab7-dependent lysosome fusion in a controlled manner. WDR91 thus maintains an appropriate level of lysosome fusion to guard the normal function and survival of neurons.