Baseline Unfolded Protein Response Signaling Adjusts the Timing of the Mammalian Cell Cycle

The endoplasmic reticulum (ER) is a single-copy organelle that cannot be generated de novo, suggesting coordination between the mechanisms overseeing ER integrity and those controlling the cell cycle to maintain organelle inheritance. The Unfolded Protein Response (UPR) is a conserved signaling network that regulates ER homeostasis. Here, we show that pharmacological and genetic inhibition of the UPR sensors IRE1, ATF6, and PERK in unstressed cells delays the cell cycle, with PERK inhibition showing the most penetrant effect, which was associated with a slowdown of the G1-to-S/G2 transition. Treatment with the small molecule ISRIB to bypass the effects of PERK-dependent phosphorylation of the translation initiation factor eIF2⍺ had no such effect, suggesting that cell cycle timing depends on PERK's kinase activity but is independent of eIF2⍺ phosphorylation. Using complementary light and electron microscopy and flow cytometry-based analyses, we also demonstrate that the ER enlarges before mitosis. Together, our results suggest coordination between UPR signaling and the cell cycle to maintain ER physiology during cell division.

Role of trafficking protein particle complex 2 in medaka development

The skeletal dysplasia spondyloepiphyseal dysplasia tarda (SEDT) is caused by mutations in the TRAPPC2 gene, which encodes Sedlin, a component of the trafficking protein particle (TRAPP) complex that we have shown previously to be required for the export of type II collagen (Col2) from the endoplasmic reticulum. No vertebrate model for SEDT has been generated thus far. To address this gap, we generated a Sedlin knockout animal by mutating the orthologous TRAPPC2 gene (olSedl) of Oryzias latipes (medaka) fish. OlSedl deficiency leads to embryonic defects, short size, diminished skeletal ossification and altered Col2 production and secretion, resembling human defects observed in SEDT patients. Moreover, SEDT knock-out animals display photoreceptor degeneration and gut morphogenesis defects, suggesting a key role for Sedlin in the development of these organs. Thus, by studying Sedlin function in vivo, we provide evidence for a mechanistic link between TRAPPC2-mediated membrane trafficking, Col2 export, and developmental disorders.

Increased expression or activation of TRPML1 reduces hepatic storage of toxic Z alpha-1 antitrypsin

Mutant Z alpha-1 antitrypsin (ATZ) accumulates in globules in the liver and is the prototype of proteotoxic hepatic disease. Therapeutic strategies aiming at clearance of polymeric ATZ are needed. Transient receptor potential mucolipin-1 (TRPML1) is a lysosomal Ca2+ channel that maintains lysosomal homeostasis. In this study, we show that by increasing lysosomal exocytosis, TRPML1 gene transfer or small-molecule-mediated activation of TRPML1 reduces hepatic ATZ globules and fibrosis in PiZ transgenic mice that express the human ATZ. ATZ globule clearance induced by TRPML1 occurred without increase in autophagy or nuclear translocation of TFEB. Our results show that targeting TRPML1 and lysosomal exocytosis is a novel approach for treatment of the liver disease due to ATZ and potentially other diseases due to proteotoxic liver storage.

The HSPB1-p62/SQSTM1 functional complex regulates the unconventional secretion and transcellular spreading of the HD-associated mutant huntingtin protein

Conformational diseases, such as Alzheimer, Parkinson and Huntington diseases, are part of a common class of neurological disorders characterized by the aggregation and progressive accumulation of proteins bearing aberrant conformations. Huntington disease (HD) has autosomal dominant inheritance and is caused by mutations leading to an abnormal expansion in the polyglutamine (polyQ) tract of the huntingtin (HTT) protein, leading to the formation of HTT inclusion bodies in neurons of affected patients. Interestingly, recent experimental evidence is challenging the conventional view by which the disease pathogenesis is solely a consequence of the intracellular accumulation of mutant protein aggregates. These studies reveal that transcellular transfer of mutated huntingtin protein is able to seed oligomers involving even the wild-type (WT) forms of the protein. To date, there is still no successful strategy to treat HD. Here, we describe a novel functional role for the HSPB1-p62/SQSTM1 complex, which acts as a cargo loading platform, allowing the unconventional secretion of mutant HTT by extracellular vesicles. HSPB1 interacts preferentially with polyQ-expanded HTT compared with the WT protein and affects its aggregation. Furthermore, HSPB1 levels correlate with the rate of mutant HTT secretion, which is controlled by the activity of the PI3K/AKT/mTOR signalling pathway. Finally, we show that these HTT-containing vesicular structures are biologically active and able to be internalized by recipient cells, therefore providing an additional mechanism to explain the prion-like spreading properties of mutant HTT. These findings might also have implications for the turn-over of other disease-associated, aggregation-prone proteins.

Loss of the batten disease protein CLN3 leads to mis-trafficking of M6PR and defective autophagic-lysosomal reformation

Batten disease, one of the most devastating types of neurodegenerative lysosomal storage disorders, is caused by mutations in CLN3. Here, we show that CLN3 is a vesicular trafficking hub connecting the Golgi and lysosome compartments. Proteomic analysis reveals that CLN3 interacts with several endo-lysosomal trafficking proteins, including the cation-independent mannose 6 phosphate receptor (CI-M6PR), which coordinates the targeting of lysosomal enzymes to lysosomes. CLN3 depletion results in mis-trafficking of CI-M6PR, mis-sorting of lysosomal enzymes, and defective autophagic lysosomal reformation. Conversely, CLN3 overexpression promotes the formation of multiple lysosomal tubules, which are autophagy and CI-M6PR-dependent, generating newly formed proto-lysosomes. Together, our findings reveal that CLN3 functions as a link between the M6P-dependent trafficking of lysosomal enzymes and lysosomal reformation pathway, explaining the global impairment of lysosomal function in Batten disease.

Genistein improves renal disease in a mouse model of nephropathic cystinosis: a comparison study with cysteamine

Cysteamine is currently the only therapy for nephropathic cystinosis. It significantly improves life expectancy and delays progression to end-stage kidney disease; however, it cannot prevent it. Unfortunately, compliance to therapy is often weak, particularly during adolescence. Therefore, finding better treatments is a priority in the field of cystinosis. Previously, we found that genistein, an isoflavone particularly enriched in soy, can revert part of the cystinotic cellular phenotype that is not sensitive to cysteamine in vitro. To test the effects of genistein in vivo, we fed 2-month-old wild-type and Ctns-/- female mice with either a control diet, a genistein-containing diet or a cysteamine-containing diet for 14 months. Genistein (160 mg/kg/day) did not affect the growth of the mice or hepatic functionality. Compared with untreated mice at 16 months, Ctns-/- mice fed with genistein had lower cystine concentrations in their kidneys, reduced formation of cystine crystals, a smaller number of LAMP1-positive structures and an overall better-preserved parenchymal architecture. Cysteamine (400 mg/kg/day) was efficient in reverting the lysosomal phenotype and in preventing the development of renal lesions. These preclinical data indicate that genistein ameliorates kidney injury resulting from cystinosis with no side effects. Genistein therapy represents a potential treatment to improve the outcome for patients with cystinosis.

Liver-directed gene therapy for ornithine aminotransferase deficiency

Gyrate atrophy of choroid and retina (GACR) is a chorioretinal degeneration caused by pathogenic variants in the gene encoding ornithine aminotransferase (OAT), an enzyme mainly expressed in liver. Affected patients have increased ornithine concentrations in blood and other body fluids and develop progressive constriction of vision fields leading to blindness. Current therapies are unsatisfactory and better treatments are highly needed. In two mouse models of OAT deficiency that recapitulates biochemical and retinal changes of GACR, we investigated the efficacy of an intravenously injected serotype 8 adeno-associated (AAV8) vector expressing OAT under the control of a hepatocyte-specific promoter. Following injections, OAT-deficient mice showed reductions of ornithine concentrations in blood and eye cups compared with control mice injected with a vector expressing green fluorescent protein. AAV-injected mice showed improved electroretinogram response and partial restoration of retinal structure up to one-year post-injection. In summary, hepatic OAT expression by AAV8 vector was effective at correction of hyperornithinemia and improved function and structure of the retina. In conclusion, this study provides proof-of-concept of efficacy of liver-directed AAV-mediated gene therapy of GACR.

TPC2 rescues lysosomal storage in mucolipidosis type IV, Niemann-Pick type C1, and Batten disease

Lysosomes are cell organelles that degrade macromolecules to recycle their components. If lysosomal degradative function is impaired, e.g., due to mutations in lysosomal enzymes or membrane proteins, lysosomal storage diseases (LSDs) can develop. LSDs manifest often with neurodegenerative symptoms, typically starting in early childhood, and going along with a strongly reduced life expectancy and quality of life. We show here that small molecule activation of the Ca²⁺‐permeable endolysosomal two‐pore channel 2 (TPC2) results in an amelioration of cellular phenotypes associated with LSDs such as cholesterol or lipofuscin accumulation, or the formation of abnormal vacuoles seen by electron microscopy. Rescue effects by TPC2 activation, which promotes lysosomal exocytosis and autophagy, were assessed in mucolipidosis type IV (MLIV), Niemann–Pick type C1, and Batten disease patient fibroblasts, and in neurons derived from newly generated isogenic human iPSC models for MLIV and Batten disease. For in vivo proof of concept, we tested TPC2 activation in the MLIV mouse model. In sum, our data suggest that TPC2 is a promising target for the treatment of different types of LSDs, both in vitro and in‐vivo.

Magnetic therapy in acute and subacute non-specific back pain: Results of an open multicenter study

Magnetic therapy (MT) is a non-drug method that improves the effectiveness of treatment of musculoskeletal pain, including:acute non-specific back pain (NBP). Objective of our study was to evaluate the results of complex treatment of patients with acute/subacute NBP at home using MT. The study group consisted of 339 patients with severe acute/subacute NBP. All patients received nonsteroidal anti-inflammatory drugs (NSAIDs). 166 patients (Group 1) received a course of MT (ALMAG+ device), 173 patients or a control group (Group 2) who did not receive MT. The dynamics of pain was significantly higher in group 1 than in group 2. So, the intensity of pain during movement (NRS) decreased from 7 [5;8] and 7 [5;8] to 0 [0;13] and 2 [1;3] after 1 month. (p<0.001). Significant differences between Groups 1 and 2 were observed in the dynamics of pain at rest and at night, overall health assessment (OHA), and sleep function and disorders. The average duration of NSAIDs use in Group 1 was 8.8±3.9, Group 2 – 11.8±5.7 days (p<0.001). The use of MT increases the effectiveness of treatment of acute/subacute NBP and reduces the need for NSAIDs use.

Induction of Autophagy Promotes Clearance of RHOP23H Aggregates and Protects From Retinal Degeneration

Autophagy is a critical metabolic process that acts as a major self-digestion and recycling pathway contributing to maintain cellular homeostasis. An emerging field of research supports the therapeutic modulation of autophagy for treating human neurodegenerative disorders, in which toxic aggregates are accumulated in neurons. Our previous study identified Ezrin protein as an inhibitor of autophagy and lysosomal functions in the retina; thus, in turn, identifying it as a potential pharmacological target for increasing retinal cell clearance to treat inherited retinal dystrophies in which misfolded proteins have accumulated. This study aimed to verify the therapeutic inhibition of Ezrin to induce clearance of toxic aggregates in a mouse model for a dominant form of retinitis pigmentosa (i.e., RHOP23H/+). We found that daily inhibition of Ezrin significantly decreased the accumulation of misfolded RHOP23H aggregates. Remarkably, induction of autophagy, by a drug-mediated pulsatile inhibition of Ezrin, promoted the lysosomal clearance of disease-linked RHOP23H aggregates. This was accompanied with a reduction of endoplasmic reticulum (ER)-stress, robust decrease of photoreceptors' cell death, amelioration in both retinal morphology and function culminating in a better preservation of vision. Our study opens new perspectives for a pulsatile pharmacological induction of autophagy as a mutation-independent therapy paving the way toward a more effective therapeutic strategy to treat these devastating retinal disorders due to an accumulation of intracellular toxic aggregates.

POS1134 THE EFFECT OF ETORICOXIB ON PAIN AND SIGNS OF CENTRAL SENSITIZATION IN PATIENTS WITH OSTEOARTHRITIS

Background

Central sensitization (CS) plays an important role in the development of chronic pain in osteoarthritis (OA).

Objectives

to evaluate the effect of etoricoxib on pain and signs of CS in patients with OA.

Methods

790 patients with OA (knee or hip) were included in an open observational study. Most of them (71.6%) were female, mean age 54.5 ± 13.0 years. All patients received etoricoxib 60 mg/day for 2 weeks. The dynamics of pain was assessed on a numerical rating scale (NRS 0-10), the dynamics of the sign of CS was assessed using the Central Sensitization Inventory (CSI). CSI ≥ 40 was observed in 35.3% of patients.

Results

After 2 weeks of treatment with etoricoxib, the intensity of pain at movement, at rest and at night decreased by 58.8±24.1%, 69.7±32.6% and 70.1±32.8. There was a decrease in CSI values ​​by 33.1±14.5% (p<0.001), as well as a decrease in the number of patients with CSI ≥40: from 35.3% to 10.3% (p<0.001). There were no serious complications during the treatment. The total number of adverse events was 5.9%, mainly dyspepsia and arterial hypertension.

Conclusion

Etoricoxib improved pain in OA patients and reduces the severity of signs of CS, supporting the central mode-of-action of the drug.

Disclosure of Interests

None declared

AB0996 The possibility of long-term pain control in patients with osteoarthritis

Background

In some patients with osteoarthritis (OA), moderate or severe joint pain may persist for a long time and functional limitations may increase, which requires long-term administration of nonsteroidal anti-inflammatory drugs (NSAIDs).

Objectives

To evaluate the efficacy and safety of long-term use of NSAIDs in patients with OA in real clinical practice.

Methods

611 patients with OA (knee or hip) were included in an open observational study. 64.5% were female, mean age 58.3±11.0years. All patients received aceclofenac at a dose of 200 mg / day. Pain at movement was determined on a 10-cm visual analog scale (VAS). The number of patients with severe pain (≥6 cm by VAS) and the number of patients with pain reduction ≥50% were evaluated. The assessment was carried out 2 weeks, 3, 6, 9 and 12 months after the start of therapy. Adverse events were noted at each visit.

Results

By 12 months of follow-up, 53.3% of patients had completed the study. The mean pain severity at baseline, after 2 weeks, 3, 6, 9 and 12 months was 6,5±1,2; 4,8±1,4; 3,2±1,4; 2,6±1,4; 2,2±1,1; 1,4±1,1 cm VAS (p<0.05). The number of patients with severe pain decreased from 77.8% to 24,9%, 2,9%, 2,3%, 0,9% and 0%. The number of patients with pain reduction ≥50% was 12,0%, 65,1%, 81,0%, 88,5% and 84.0%. Adverse events were observed in about 30% of patients, mainly mild or moderate dyspepsia (11.1%- 23.3%) and arterial hypertension (7.1% - 10.9%). No serious complications were recorded.

Conclusion

Taking into account the large number of drop-outs from the study (46.7%), approximately half of the patients can have long-term pain control with NSAIDs in real clinical practice. Aceclofenac is effective and well tolerated and can be used for long-term pain control in patients with OA.

Disclosure of Interests

None declared

Down Syndrome Fetal Fibroblasts Display Alterations of Endosomal Trafficking Possibly due to SYNJ1 Overexpression

Endosomal trafficking is essential for cellular homeostasis. At the crossroads of distinct intracellular pathways, the endolysosomal system is crucial to maintain critical functions and adapt to the environment. Alterations of endosomal compartments were observed in cells from adult individuals with Down syndrome (DS), suggesting that the dysfunction of the endosomal pathway may contribute to the pathogenesis of DS. However, the nature and the degree of impairment, as well as the timing of onset, remain elusive. Here, by applying imaging and biochemical approaches, we demonstrate that the structure and dynamics of early endosomes are altered in DS cells. Furthermore, we found that recycling trafficking is markedly compromised in these cells. Remarkably, our results in 18–20 week-old human fetal fibroblasts indicate that alterations in the endolysosomal pathway are already present early in development. In addition, we show that overexpression of the polyphosphoinositide phosphatase synaptojanin 1 (Synj1) recapitulates the alterations observed in DS cells, suggesting a role for this lipid phosphatase in the pathogenesis of DS, likely already early in disease development. Overall, these data strengthen the link between the endolysosomal pathway and DS, highlighting a dangerous liaison among Synj1, endosomal trafficking and DS.

Correction of oxidative stress enhances enzyme replacement therapy in Pompe disease

Pompe disease is a metabolic myopathy due to acid alpha-glucosidase deficiency. In addition to glycogen storage, secondary dysregulation of cellular functions, such as autophagy and oxidative stress, contributes to the disease pathophysiology. We have tested whether oxidative stress impacts on enzyme replacement therapy with recombinant human alpha-glucosidase (rhGAA), currently the standard of care for Pompe disease patients, and whether correction of oxidative stress may be beneficial for rhGAA therapy. We found elevated oxidative stress levels in tissues from the Pompe disease murine model and in patients' cells. In cells, stress levels inversely correlated with the ability of rhGAA to correct the enzymatic deficiency. Antioxidants (N-acetylcysteine, idebenone, resveratrol, edaravone) improved alpha-glucosidase activity in rhGAA-treated cells, enhanced enzyme processing, and improved mannose-6-phosphate receptor localization. When co-administered with rhGAA, antioxidants improved alpha-glucosidase activity in tissues from the Pompe disease mouse model. These results indicate that oxidative stress impacts on the efficacy of enzyme replacement therapy in Pompe disease and that manipulation of secondary abnormalities may represent a strategy to improve the efficacy of therapies for this disorder.

Role of FAM134 paralogues in endoplasmic reticulum remodeling, ER-phagy, and Collagen quality control

Degradation of the endoplasmic reticulum (ER) via selective autophagy (ER‐phagy) is vital for cellular homeostasis. We identify FAM134A/RETREG2 and FAM134C/RETREG3 as ER‐phagy receptors, which predominantly exist in an inactive state under basal conditions. Upon autophagy induction and ER stress signal, they can induce significant ER fragmentation and subsequent lysosomal degradation. FAM134A, FAM134B/RETREG1, and FAM134C are essential for maintaining ER morphology in a LC3‐interacting region (LIR)‐dependent manner. Overexpression of any FAM134 paralogue has the capacity to significantly augment the general ER‐phagy flux upon starvation or ER‐stress. Global proteomic analysis of FAM134 overexpressing and knockout cell lines reveals several protein clusters that are distinctly regulated by each of the FAM134 paralogues as well as a cluster of commonly regulated ER‐resident proteins. Utilizing pro‐Collagen I, as a shared ER‐phagy substrate, we observe that FAM134A acts in a LIR‐independent manner and compensates for the loss of FAM134B and FAM134C, respectively. FAM134C instead is unable to compensate for the loss of its paralogues. Taken together, our data show that FAM134 paralogues contribute to common and unique ER‐phagy pathways.

Beclin-1-mediated activation of autophagy improves proximal and distal urea cycle disorders

Urea cycle disorders (UCD) are inherited defects in clearance of waste nitrogen with high morbidity and mortality. Novel and more effective therapies for UCD are needed. Studies in mice with constitutive activation of autophagy unravelled Beclin-1 as druggable candidate for therapy of hyperammonemia. Next, we investigated efficacy of cell-penetrating autophagy-inducing Tat-Beclin-1 (TB-1) peptide for therapy of the two most common UCD, namely ornithine transcarbamylase (OTC) and argininosuccinate lyase (ASL) deficiencies. TB-1 reduced urinary orotic acid and improved survival under protein-rich diet in spf-ash mice, a model of OTC deficiency (proximal UCD). In AslNeo/Neo mice, a model of ASL deficiency (distal UCD), TB-1 increased ureagenesis, reduced argininosuccinate, and improved survival. Moreover, it alleviated hepatocellular injury and decreased both cytoplasmic and nuclear glycogen accumulation in AslNeo/Neo mice. In conclusion, Beclin-1-dependent activation of autophagy improved biochemical and clinical phenotypes of proximal and distal defects of the urea cycle.

The incidence of dry chlorhexidine gluconate transfer from skin to surgical gloves: a simulation and in vitro study

BACKGROUND

To prevent alcohol-based chlorhexidine from reaching the cerebrospinal fluid, it is recommended that the antiseptic solution be allowed to dry before skin palpation or puncture. However, no guidelines specify a drying time interval. Manufacturers recommend 3 min of air drying, based upon the isopropyl alcohol component. Therefore, to fill this knowledge gap, we designed a simulation study to investigate the incidence of primary chlorhexidine transfer from skin to gloves following three drying time intervals. We also investigated the incidence of secondary chlorhexidine transfer from gloves to another surface following one drying time interval.

METHODS

An alcohol-based chlorhexidine antiseptic solution with dye, ChloraPrep®, was applied to the skin of the lumbar region of 20 volunteers. Cotton-tipped applicators wrapped in material from gloves were taken from the application area at 3, 4, 5, and 10 min following application. Transfer of chlorhexidine from skin to gloves, and gloves to another medium, was assessed through a chemical assay that produced a color change when chlorhexidine was present on the sample.

RESULTS

The incidence of primary chlorhexidine transfer from skin to gloves at 3, 4 and 10 min following application was 99.5%, 99.4%, and 99.6%, respectively. The incidence of secondary chlorhexidine transfer from gloves to another surface was 68.9%.

CONCLUSION

Gloves are routinely contaminated with chlorhexidine during central neuraxial blockade. The high incidence of secondary transfer in our simulation suggests a pathway by which chlorhexidine may gain access to the neuraxial space.

MiT/TFE factors control ER-phagy via transcriptional regulation of FAM134B

Lysosomal degradation of the endoplasmic reticulum (ER) via autophagy (ER-phagy) is emerging as a critical regulator of cell homeostasis and function. The recent identification of ER-phagy receptors has shed light on the molecular mechanisms underlining this process. However, the signaling pathways regulating ER-phagy in response to cellular needs are still largely unknown. We found that the nutrient responsive transcription factors TFEB and TFE3-master regulators of lysosomal biogenesis and autophagy-control ER-phagy by inducing the expression of the ER-phagy receptor FAM134B. The TFEB/TFE3-FAM134B axis promotes ER-phagy activation upon prolonged starvation. In addition, this pathway is activated in chondrocytes by FGF signaling, a critical regulator of skeletal growth. FGF signaling induces JNK-dependent proteasomal degradation of the insulin receptor substrate 1 (IRS1), which in turn inhibits the PI3K-PKB/Akt-mTORC1 pathway and promotes TFEB/TFE3 nuclear translocation and enhances FAM134B transcription. Notably, FAM134B is required for protein secretion in chondrocytes, and cartilage growth and bone mineralization in medaka fish. This study identifies a new signaling pathway that allows ER-phagy to respond to both metabolic and developmental cues.

Intein-mediated protein trans-splicing expands adeno-associated virus transfer capacity in the retina

Retinal gene therapy with adeno-associated viral (AAV) vectors holds promises for treating inherited and noninherited diseases of the eye. Although clinical data suggest that retinal gene therapy is safe and effective, delivery of large genes is hindered by the limited AAV cargo capacity. Protein trans-splicing mediated by split inteins is used by single-cell organisms to reconstitute proteins. Here, we show that delivery of multiple AAV vectors each encoding one of the fragments of target proteins flanked by short split inteins results in protein trans-splicing and full-length protein reconstitution in the retina of mice and pigs and in human retinal organoids. The reconstitution of large therapeutic proteins using this approach improved the phenotype of two mouse models of inherited retinal diseases. Our data support the use of split intein-mediated protein trans-splicing in combination with AAV subretinal delivery for gene therapy of inherited blindness due to mutations in large genes.

Light-responsive microRNA miR-211 targets Ezrin to modulate lysosomal biogenesis and retinal cell clearance

Vertebrate vision relies on the daily phagocytosis and lysosomal degradation of photoreceptor outer segments (POS) within the retinal pigment epithelium (RPE). However, how these events are controlled by light is largely unknown. Here, we show that the light-responsive miR-211 controls lysosomal biogenesis at the beginning of light-dark transitions in the RPE by targeting Ezrin, a cytoskeleton-associated protein essential for the regulation of calcium homeostasis. miR-211-mediated down-regulation of Ezrin leads to Ca²⁺ influx resulting in the activation of calcineurin, which in turn activates TFEB, the master regulator of lysosomal biogenesis. Light-mediated induction of lysosomal biogenesis and function is impaired in the RPE from miR-211^-/- mice that show severely compromised vision. Pharmacological restoration of lysosomal biogenesis through Ezrin inhibition rescued the miR-211^-/- phenotype, pointing to a new therapeutic target to counteract retinal degeneration associated with lysosomal dysfunction.

TRPML1 links lysosomal calcium to autophagosome biogenesis through the activation of the CaMKKβ/VPS34 pathway

The lysosomal calcium channel TRPML1, whose mutations cause the lysosomal storage disorder (LSD) mucolipidosis type IV (MLIV), contributes to upregulate autophagic genes by inducing the nuclear translocation of the transcription factor EB (TFEB). Here we show that TRPML1 activation also induces autophagic vesicle (AV) biogenesis through the generation of phosphatidylinositol 3-phosphate (PI3P) and the recruitment of essential PI3P-binding proteins to the nascent phagophore in a TFEB-independent manner. Thus, TRPML1 activation of phagophore formation requires the calcium-dependent kinase CaMKKβ and AMPK, which increase the activation of ULK1 and VPS34 autophagic protein complexes. Consistently, cells from MLIV patients show a reduced recruitment of PI3P-binding proteins to the phagophore during autophagy induction, suggesting that altered AV biogenesis is part of the pathological features of this disease. Together, we show that TRPML1 is a multistep regulator of autophagy that may be targeted for therapeutic purposes to treat LSDs and other autophagic disorders.

It was known that prolonged TRMPL1 activation induces TFEB translocation and upregulates autophagic gene regulation. Here, the authors show that acute TRMPL1 activation also induces autophagy through VPS34 and by lysosomal calcium release independent of TFEB.

The TRAPP complex mediates secretion arrest induced by stress granule assembly

The TRAnsport Protein Particle (TRAPP) complex controls multiple membrane trafficking steps and is strategically positioned to mediate cell adaptation to diverse environmental conditions, including acute stress. We have identified the TRAPP complex as a component of a branch of the integrated stress response that impinges on the early secretory pathway. The TRAPP complex associates with and drives the recruitment of the COPII coat to stress granules (SGs) leading to vesiculation of the Golgi complex and arrest of ER export. The relocation of the TRAPP complex and COPII to SGs only occurs in cycling cells and is CDK1/2-dependent, being driven by the interaction of TRAPP with hnRNPK, a CDK substrate that associates with SGs when phosphorylated. In addition, CDK1/2 inhibition impairs TRAPP complex/COPII relocation to SGs while stabilizing them at ER exit sites. Importantly, the TRAPP complex controls the maturation of SGs. SGs that assemble in TRAPP-depleted cells are smaller and are no longer able to recruit RACK1 and Raptor, two TRAPP-interactive signaling proteins, sensitizing cells to stress-induced apoptosis.

Skin fibroblasts of patients with geleophysic dysplasia due to FBN1 mutations have lysosomal inclusions and losartan improves their microfibril deposition defect

Background

Geleophysic dysplasia (GPHYSD) is a disorder characterized by dysmorphic features, stiff joints and cardiac involvement due to defects of TGF‐β signaling. GPHYSD can be caused by mutations in FBN1, ADAMTLS2, and LTBP3 genes.

Methods and Results

Consistent with previous reports, we found intracellular inclusions of unknown material by electron microscopy (EM) in skin fibroblasts of two GPHYSD individuals carrying FBN1 mutations. Moreover, we found that the storage material is enclosed within lysosomes and is associated with the upregulation of several lysosomal genes. Treatment of GPHYSD fibroblasts carrying FBN1 mutations with the angiotensin II receptor type 1 inhibitor losartan that inhibits TGF‐β signaling did not reduce the storage but improved the extracellular deposition of fibrillin‐1 microfibrils.

Conclusion

Losartan is a promising candidate drug for treatment of GPHYSD due to FBN1 defects.

PERK-Mediated Unfolded Protein Response Activation and Oxidative Stress in PARK20 Fibroblasts

PARK20, an early onset autosomal recessive parkinsonism is due to mutations in the phosphatidylinositol-phosphatase Synaptojanin 1 (Synj1). We have recently shown that the early endosomal compartments are profoundly altered in PARK20 fibroblasts as well as the endosomal trafficking. Here, we report that PARK20 fibroblasts also display a drastic alteration of the architecture and function of the early secretory compartments. Our results show that the exit machinery from the Endoplasmic Reticulum (ER) and the ER-to-Golgi trafficking are markedly compromised in patient cells. As a consequence, PARK20 fibroblasts accumulate large amounts of cargo proteins within the ER, leading to the induction of ER stress. Interestingly, this stressful state is coupled to the activation of the PERK/eIF2α/ATF4/CHOP pathway of the Unfolded Protein Response (UPR). In addition, PARK20 fibroblasts reveal upregulation of oxidative stress markers and total ROS production with concomitant alteration of the morphology of the mitochondrial network. Interestingly, treatment of PARK20 cells with GSK2606414 (GSK), a specific inhibitor of PERK activity, restores the level of ROS, signaling a direct correlation between ER stress and the induction of oxidative stress in the PARK20 cells. All together, these findings suggest that dysfunction of early secretory pathway might contribute to the pathogenesis of the disease.

The activity of Sac1 across ER-TGN contact sites requires the four-phosphate-adaptor-protein-1

Venditti et al. identify FAPP1 as a new determinant of ER–trans-Golgi network contacts that interacts with the phosphoinositide phosphatase Sac1 and promotes its phosphatase activity. The results suggest that, by controlling PI4P levels, FAPP1 acts as a gatekeeper of cargo Golgi exit.

Phosphatidylinositol-4-phosphate (PI4P), a phosphoinositide with key roles in the Golgi complex, is made by Golgi-associated phosphatidylinositol-4 kinases and consumed by the 4-phosphatase Sac1 that, instead, is an ER membrane protein. Here, we show that the contact sites between the ER and the TGN (ERTGoCS) provide a spatial setting suitable for Sac1 to dephosphorylate PI4P at the TGN. The ERTGoCS, though necessary, are not sufficient for the phosphatase activity of Sac1 on TGN PI4P, since this needs the phosphatidyl-four-phosphate-adaptor-protein-1 (FAPP1). FAPP1 localizes at ERTGoCS, interacts with Sac1, and promotes its in-trans phosphatase activity in vitro. We envision that FAPP1, acting as a PI4P detector and adaptor, positions Sac1 close to TGN domains with elevated PI4P concentrations allowing PI4P consumption. Indeed, FAPP1 depletion induces an increase in TGN PI4P that leads to increased secretion of selected cargoes (e.g., ApoB100), indicating that FAPP1, by controlling PI4P levels, acts as a gatekeeper of Golgi exit.

Molecular determinants of ER-Golgi contacts identified through a new FRET-FLIM system

ER-TGN contact sites (ERTGoCS) have been visualized by electron microscopy, but their location in the crowded perinuclear area has hampered their analysis via optical microscopy as well as their mechanistic study. To overcome these limits we developed a FRET-based approach and screened several candidates to search for molecular determinants of the ERTGoCS. These included the ER membrane proteins VAPA and VAPB and lipid transfer proteins possessing dual (ER and TGN) targeting motifs that have been hypothesized to contribute to the maintenance of ERTGoCS, such as the ceramide transfer protein CERT and several members of the oxysterol binding proteins. We found that VAP proteins, OSBP1, ORP9, and ORP10 are required, with OSBP1 playing a redundant role with ORP9, which does not involve its lipid transfer activity, and ORP10 being required due to its ability to transfer phosphatidylserine to the TGN. Our results indicate that both structural tethers and a proper lipid composition are needed for ERTGoCS integrity.

Gallium(iii) and iron(iii) complexes of quinolone antimicrobials

Iron is an essential nutrient for many microbes. According to the "Trojan Horse Hypothesis", biological systems have difficulties distinguishing between Fe(3+) and Ga(3+), which constitutes the antimicrobial efficacy of the gallium(iii) ion. Nine novel tris(quinolono)gallium(iii) complexes and their corresponding iron(iii) analogs have been synthesized and fully characterized. Quinolone antimicrobial agents from three drug generations were used in this study: ciprofloxacin, enoxacin, fleroxacin, levofloxacin, lomefloxacin, nalidixic acid, norfloxacin, oxolinic acid, and pipemidic acid. The antimicrobial efficacy of the tris(quinolono)gallium(iii) complexes was studied against E. faecalis and S. aureus (both Gram-positive), as well as E. coli, K. pneumonia, and P. aeruginosa (all Gram-negative) in direct comparison to the tris(quinolono)iron(iii) complexes and the corresponding free quinolone ligands at various concentrations. For the tris(quinolono)gallium(iii) complexes, no combinational antimicrobial effects between Ga(3+) and the quinolone antimicrobial agents were observed.

AAV-mediated transcription factor EB (TFEB) gene delivery ameliorates muscle pathology and function in the murine model of Pompe Disease

Pompe disease (PD) is a metabolic myopathy due to acid alpha-glucosidase deficiency and characterized by extensive glycogen storage and impaired autophagy. We previously showed that modulation of autophagy and lysosomal exocytosis by overexpression of the transcription factor EB (TFEB) gene was effective in improving muscle pathology in PD mice injected intramuscularly with an AAV-TFEB vector. Here we have evaluated the effects of TFEB systemic delivery on muscle pathology and on functional performance, a primary measure of efficacy in a disorder like PD. We treated 1-month-old PD mice with an AAV2.9-MCK-TFEB vector. An animal cohort was analyzed at 3 months for muscle and heart pathology. A second cohort was followed at different timepoints for functional analysis. In muscles from TFEB-treated mice we observed reduced PAS staining and improved ultrastructure, with reduced number and increased translucency of lysosomes, while total glycogen content remained unchanged. We also observed statistically significant improvements in rotarod performance in treated animals compared to AAV2.9-MCK-eGFP-treated mice at 5 and 8 months. Cardiac echography showed significant reduction in left-ventricular diameters. These results show that TFEB overexpression and modulation of autophagy result in improvements of muscle pathology and of functional performance in the PD murine model, with delayed disease progression.

Uroplakin traffic through the Golgi apparatus induces its fragmentation: new insights from novel in vitro models

Uroplakins (UPs) play an essential role in maintaining an effective urothelial permeability barrier at the level of superficial urothelial cell (UC) layer. Although the organization of UPs in the apical plasma membrane (PM) of UCs is well known, their transport in UCs is only partially understood. Here, we dissected trafficking of UPs and its differentiation-dependent impact on Golgi apparatus (GA) architecture. We demonstrated that individual subunits UPIb and UPIIIa are capable of trafficking from the endoplasmic reticulum to the GA in UCs. Moreover, UPIb, UPIIIa or UPIb/UPIIIa expressing UCs revealed fragmentation and peripheral redistribution of Golgi-units. Notably, expression of UPIb or UPIb/UPIIIa triggered similar GA fragmentation in MDCK and HeLa cells that do not express UPs endogenously. The colocalization analysis of UPIb/UPIIIa-EGFP and COPI, COPII or clathrin suggested that UPs follow constitutively the post-Golgi route to the apical PM. Depolymerisation of microtubules leads to complete blockade of the UPIb/UPIIIa-EGFP post-Golgi transport, while disassembly of actin filaments shows significantly reduced delivery of UPIb/UPIIIa-EGFP to the PM. Our findings show the significant effect of the UPs expression on the GA fragmentation, which enables secretory Golgi-outpost to be distributed as close as possible to the sites of cargo delivery at the PM.

ER/Golgi trafficking is facilitated by unbranched actin filaments containing Tpm4.2

We have identified novel actin filaments defined by tropomyosin Tpm4.2 at the ER. EM analysis of mouse embryo fibroblasts (MEFs) isolated from mice expressing a mutant Tpm4.2 (Tpm4^Plt53/Plt53 ), incapable of incorporating into actin filaments, revealed swollen ER structures compared with wild-type (WT) MEFs (Tpm4^+/+ ). ER-to-Golgi, but not Golgi-to-ER trafficking was altered in the Tpm4^Plt53/Plt53 MEFs following the transfection of the temperature sensitive ER-associated ts045-VSVg construct. Exogenous Tpm4.2 was able to rescue the ER-to-Golgi trafficking defect in the Tpm4^Plt53/Plt53 cells. The treatment of WT MEFs with the myosin II inhibitor, blebbistatin, blocked the Tpm4.2-dependent ER-to-Golgi trafficking. The lack of an effect on ER-to-Golgi trafficking following treatment of MEFs with CK666 indicates that branched Arp2/3-containing actin filaments are not involved in anterograde vesicle trafficking. We propose that unbranched, Tpm4.2-containing filaments have an important role in maintaining ER/Golgi structure and that these structures, in conjunction with myosin II motors, mediate ER-to-Golgi trafficking.

Metformin restores the mitochondrial network and reverses mitochondrial dysfunction in Down syndrome cells

Alterations in mitochondrial activity and morphology have been demonstrated in human cells and tissues from individuals with Down syndrome (DS), as well as in DS mouse models. An impaired activity of the transcriptional coactivator PGC-1α/PPARGC1A due to the overexpression of chromosome 21 genes, such as NRIP1/RIP140, has emerged as an underlying cause of mitochondrial dysfunction in DS. We tested the hypothesis that the activation of the PGC-1α pathway might indeed reverse this mitochondrial dysfunction. To this end, we investigated the effects of metformin, a PGC-1α-activating drug, on mitochondrial morphology and function in DS foetal fibroblasts. Metformin induced both the expression of PGC-1α and an augmentation of its activity, as demonstrated by the increased expression of target genes, strongly promoting mitochondrial biogenesis. Furthermore, metformin enhanced oxygen consumption, ATP production, and overall mitochondrial activity. Most interestingly, this treatment reversed the fragmentation of mitochondria observed in DS and induced the formation of a mitochondrial network with a branched and elongated tubular morphology. Concomitantly, cristae remodelling occurred and the alterations observed by electron microscopy were significantly reduced. We finally demonstrated that the expression of genes of the fission/fusion machinery, namely OPA1 and MFN2, was reduced in trisomic cells and increased by metformin treatment. These results indicate that metformin promotes the formation of a mitochondrial network and corrects the mitochondrial dysfunction in DS cells. We speculate that alterations in the mitochondrial dynamics can be relevant in the pathogenesis of DS and that metformin can efficiently counteract these alterations, thus exerting protective effects against DS-associated pathologies.

Activation of the transcription factor EB rescues lysosomal abnormalities in cystinotic kidney cells

Nephropathic cystinosis is a rare autosomal recessive lysosomal storage disease characterized by accumulation of cystine into lysosomes secondary to mutations in the cystine lysosomal transporter, cystinosin. The defect initially causes proximal tubular dysfunction (Fanconi syndrome) which in time progresses to end-stage renal disease. Cystinotic patients treated with the cystine-depleting agent, cysteamine, have improved life expectancy, delayed progression to chronic renal failure, but persistence of Fanconi syndrome. Here, we have investigated the role of the transcription factor EB (TFEB), a master regulator of the autophagy-lysosomal pathway, in conditionally immortalized proximal tubular epithelial cells derived from the urine of a healthy volunteer or a cystinotic patient. Lack of cystinosin reduced TFEB expression and induced TFEB nuclear translocation. Stimulation of endogenous TFEB activity by genistein, or overexpression of exogenous TFEB lowered cystine levels within 24 hours in cystinotic cells. Overexpression of TFEB also stimulated delayed endocytic cargo processing within 24 hours. Rescue of other abnormalities of the lysosomal compartment was observed but required prolonged expression of TFEB. These abnormalities could not be corrected with cysteamine. Thus, these data show that the consequences of cystinosin deficiency are not restricted to cystine accumulation and support the role of TFEB as a therapeutic target for the treatment of lysosomal storage diseases, in particular of cystinosis.

Abnormal cell-clearance and accumulation of autophagic vesicles in lymphocytes from patients affected with Ataxia-Teleangiectasia

Ataxia-Teleangiectasia (A-T) is a neurodegenerative disorder due to mutations in ATM gene. ATM in the nucleus ensures DNA repair, while its role in the cytosol is still poorly clarified. Abnormal autophagy has been documented in other neurodegenerative disorders, thus we evaluated whether alteration in this process may be involved in the pathogenesis of A-T by analyzing the autophagic vesicles and the genes implicated in the different stages of autophagy. Through transmission electron microscopy (TEM) and immunofluorescence analysis we observed an accumulation of APs associated with a LC3 puncta pattern, and a reduced number of ALs. We also documented an increased expression of genes involved in AP and lysosome biogenesis and function, and a decrease of Vps18 expression, involved in their vesicular trafficking and fusion. mTORC1-controlled proteins were hyperphosphorylated in A-T, in keeping with an increased mTOR inhibitory influence of autophagy. Betamethasone is able to promote the degradation of SQSTM1, a biomarker of autophagy. Collectively, our results indicate that in cells from A-T patients, the APs maturation is active, while the fusion between APs and lysosomes is inappropriate, thus implying abnormalities in the cell-clearance process. We also documented a positive effect of Betamethasone on molecules implicated in autophagosome degradation.

ER reorganization is remarkably induced in COS-7 cells accumulating transmembrane protein receptors not competent for export from the endoplasmic reticulum

The newly synthesized mutant L501fsX533 Frizzled-4 form and the alpha3beta4 nicotinic acetylcholine receptor expressed in the absence of nicotine accumulate in the endoplasmic reticulum of COS-7 cells and induce the formation of large areas of smooth and highly convoluted cisternae. This results in a generalized block of the transport to the Golgi complex of newly synthesized proteins. Intriguingly, both effects happen peculiarly in COS-7 cells; HeLa, Huh-7, and HEK293 cells expressing the two receptors at similar level than COS-7 cells show normal ER and normal transport toward the plasma membrane. These results question the conclusion that a dominant-negative mechanism would explain the dominance of the mutant L501fsX533 Fz4 allele in the transmission of a form of Familial exudative vitreoretinopathy. Moreover, they indicate that the coordination of endoplasmic reticulum homeostasis in COS-7 cells is particularly error prone. This finding suggests that COS-7 cells may be extremely useful to study the molecular mechanisms regulating endoplasmic reticulum size and architecture.

Myosin7a deficiency results in reduced retinal activity which is improved by gene therapy

Mutations in MYO7A cause autosomal recessive Usher syndrome type IB (USH1B), one of the most frequent conditions that combine severe congenital hearing impairment and retinitis pigmentosa. A promising therapeutic strategy for retinitis pigmentosa is gene therapy, however its pre-clinical development is limited by the mild retinal phenotype of the shaker1 (sh1^−/−) murine model of USH1B which lacks both retinal functional abnormalities and degeneration. Here we report a significant, early-onset delay of sh1^−/− photoreceptor ability to recover from light desensitization as well as a progressive reduction of both b-wave electroretinogram amplitude and light sensitivity, in the absence of significant loss of photoreceptors up to 12 months of age. We additionally show that subretinal delivery to the sh1^−/− retina of AAV vectors encoding the large MYO7A protein results in significant improvement of sh1^−/− photoreceptor and retinal pigment epithelium ultrastructural anomalies which is associated with improvement of recovery from light desensitization. These findings provide new tools to evaluate the efficacy of experimental therapies for USH1B. In addition, although AAV vectors expressing large genes might have limited clinical applications due to their genome heterogeneity, our data show that AAV-mediated MYO7A gene transfer to the sh1^−/− retina is effective.

A highly secreted sulphamidase engineered to cross the blood-brain barrier corrects brain lesions of mice with mucopolysaccharidoses type IIIA

Mucopolysaccharidoses type IIIA (MPS-IIIA) is a neurodegenerative lysosomal storage disorder (LSD) caused by inherited defects of the sulphamidase gene. Here, we used a systemic gene transfer approach to demonstrate the therapeutic efficacy of a chimeric sulphamidase, which was engineered by adding the signal peptide (sp) from the highly secreted iduronate-2-sulphatase (IDS) and the blood-brain barrier (BBB)-binding domain (BD) from the Apolipoprotein B (ApoB-BD). A single intravascular administration of AAV2/8 carrying the modified sulphamidase was performed in adult MPS-IIIA mice in order to target the liver and convert it to a factory organ for sustained systemic release of the modified sulphamidase. We showed that while the IDS sp replacement results in increased enzyme secretion, the addition of the ApoB-BD allows efficient BBB transcytosis and restoration of sulphamidase activity in the brain of treated mice. This, in turn, resulted in an overall improvement of brain pathology and recovery of a normal behavioural phenotype. Our results provide a novel feasible strategy to develop minimally invasive therapies for the treatment of brain pathology in MPS-IIIA and other neurodegenerative LSDs.

Gene transfer of master autophagy regulator TFEB results in clearance of toxic protein and correction of hepatic disease in alpha-1-anti-trypsin deficiency

Alpha-1-anti-trypsin deficiency is the most common genetic cause of liver disease in children and liver transplantation is currently the only available treatment. Enhancement of liver autophagy increases degradation of mutant, hepatotoxic alpha-1-anti-trypsin (ATZ). We investigated the therapeutic potential of liver-directed gene transfer of transcription factor EB (TFEB), a master gene that regulates lysosomal function and autophagy, in PiZ transgenic mice, recapitulating the human hepatic disease. Hepatocyte TFEB gene transfer resulted in dramatic reduction of hepatic ATZ, liver apoptosis and fibrosis, which are key features of alpha-1-anti-trypsin deficiency. Correction of the liver phenotype resulted from increased ATZ polymer degradation mediated by enhancement of autophagy flux and reduced ATZ monomer by decreased hepatic NFκB activation and IL-6 that drives ATZ gene expression. In conclusion, TFEB gene transfer is a novel strategy for treatment of liver disease of alpha-1-anti-trypsin deficiency. This study may pave the way towards applications of TFEB gene transfer for treatment of a wide spectrum of human disorders due to intracellular accumulation of toxic proteins.

Molecular events initiating exit of a copper-transporting ATPase ATP7B from the trans-Golgi network

The copper-transporting ATPase ATP7B has a dual intracellular localization: the trans-Golgi network (TGN) and cytosolic vesicles. Changes in copper levels, kinase-mediated phosphorylation, and mutations associated with Wilson disease alter the steady-state distribution of ATP7B between these compartments. To identify a primary molecular event that triggers ATP7B exit from the TGN, we characterized the folding, activity, and trafficking of the ATP7B variants with mutations within the regulatory N-terminal domain (N-ATP7B). We found that structural changes disrupting the inter-domain contacts facilitate ATP7B exit from the TGN. Mutating Ser-340/341 in the N-ATP7B individually or together to Ala, Gly, Thr, or Asp produced active protein and shifted the steady-state localization of ATP7B to vesicles, independently of copper levels. The Ser340/341G mutant had a lower kinase-mediated phosphorylation under basal conditions and no copper-dependent phosphorylation. Thus, negative charges introduced by copper-dependent phosphorylation are not obligatory for ATP7B trafficking from the TGN. The Ser340/341A mutation did not alter the overall fold of N-ATP7B, but significantly decreased interactions with the nucleotide-binding domain, mimicking consequences of copper binding to N-ATP7B. We propose that structural changes that specifically alter the inter-domain contacts initiate exit of ATP7B from the TGN, whereas increased phosphorylation may be needed to maintain an open interface between the domains.

Abnormal mannose-6-phosphate receptor trafficking impairs recombinant alpha-glucosidase uptake in Pompe disease fibroblasts

Background

Pompe disease (PD) is a metabolic myopathy caused by α-glucosidase (GAA) deficiency and characterized by generalized glycogen storage. Heterogeneous GAA gene mutations result in wide phenotypic variability, ranging from the severe classic infantile presentation to the milder intermediate and late-onset forms. Enzyme replacement therapy (ERT) with recombinant human GAA (rhGAA), the only treatment available for PD, intriguingly shows variable efficacy in different PD patients. To investigate the mechanisms underlying the variable response to ERT, we studied cell morphology of PD fibroblasts, the distribution and trafficking of the cation-independent mannose-6-phosphate receptor (CI-MPR) that mediates rhGAA uptake, and rhGAA uptake itself.

Results

We observed abnormalities of cell morphology in PD cells. Electron microscopy analysis showed accumulation of multivesicular bodies and expansion of the Golgi apparatus, and immunolocalization and western blot analysis of LC3 showed activation of autophagy. Immunofluorescence analysis showed abnormal intracellular distribution of CI-MPR in PD fibroblasts, increased co-localization with LC3 and reduced availability of the receptor at the plasma membrane. The recycling of CI-MPR from the plasma membrane to the trans-Golgi network was also impaired. All these abnormalities were more prominent in severe and intermediate PD fibroblasts, correlating with disease severity. In severe and intermediate PD cells rhGAA uptake and processing were less efficient and correction of GAA activity was reduced.

Conclusion

These results indicate a role for disrupted CI-MPR trafficking in the variable response to ERT in PD and have implications for ERT efficacy and optimization of treatment protocols.

Glycosphingolipid synthesis requires FAPP2 transfer of glucosylceramide

The molecular machinery responsible for the generation of transport carriers moving from the Golgi complex to the plasma membrane relies on a tight interplay between proteins and lipids. Among the lipid-binding proteins of this machinery, we previously identified the four-phosphate adaptor protein FAPP2, the pleckstrin homology domain of which binds phosphatidylinositol 4-phosphate and the small GTPase ARF1. FAPP2 also possesses a glycolipid-transfer-protein homology domain. Here we show that human FAPP2 is a glucosylceramide-transfer protein that has a pivotal role in the synthesis of complex glycosphingolipids, key structural and signalling components of the plasma membrane. The requirement for FAPP2 makes the whole glycosphingolipid synthetic pathway sensitive to regulation by phosphatidylinositol 4-phosphate and ARF1. Thus, by coupling the synthesis of glycosphingolipids with their export to the cell surface, FAPP2 emerges as crucial in determining the lipid identity and composition of the plasma membrane.

Synthesis, Structure, and Biological Activity of Ferrocenyl Carbohydrate Conjugates

Seven ferrocenyl carbohydrate conjugates were synthesized. Coupling reactions of monosaccharide derivatives with ferrocene carbonyl chloride produced {6-N-(methyl 2,3,4-tri-O-acetyl-6-amino-6-deoxy-alpha-D-glucopyranoside)}-1-ferrocene carboxamide (3), {1-O-(2,3,4,6-tetra-O-benzyl-D-glucopyranose)}-1-ferrocene carboxylate (4), and {6-O-(1,2,3,4-tetra-O-acetyl-beta-D-glucopyranose)}-1-ferrocene carboxylate (5). Similarly, 1,1'-bis(carbonyl chloride)ferrocene was coupled with the appropriate sugars to produce the disubstituted analogues bis{6-N-(methyl 2,3,4-tri-O-acetyl-6-amino-6-deoxy-alpha-D-glucopyranoside)}-1,1'-ferrocene carboxamide (8), bis{1-O-(2,3,4,6-tetra-O-benzyl-D-glucopyranose)}-1,1'-ferrocene carboxylate (9), and bis{6-O-(1,2,3,4-tetra-O-acetyl-beta-D-glucopyranose)}-1,1'-ferrocene carboxylate (10). {6-N-(Methyl-6-amino-6-deoxy-alpha-D-glucopyranoside)}-1-ferrocene carboxamide monohydrate (12) was synthesized via amide coupling of an activated ferrocenyl ester with the corresponding carbohydrate. All compounds were characterized by elemental analysis, 1H NMR spectroscopy, and mass spectrometry. X-ray crystallography confirmed the solid-state structure of three ferrocenyl carbohydrate conjugates: 2-N-(1,3,4,6-tetra-O-acetyl-2-amino-2-deoxy-D-glucopyranose)-1-ferrocene carboxamide (1), 1-S-(2,3,4,6-tetra-O-acetyl-1-deoxy-1-thio-D-glucopyranose)-1-ferrocene carboxylate (2), and 12. The above compounds, along with bis{2-N-(1,3,4,6-tetra-O-acetyl-2-amino-2-deoxy-D-glucopyranose)}-1,1'-ferrocene carboxamide (6), bis{1-S-(2,3,4,6-tetra-O-acetyl-1-deoxy-1-thio-D-glucopyranose)}-1,1'-ferrocene carboxylate (7), and 2-N-(2-amino-2-deoxy-D-glucopyranose)-1-ferrocene carboxamide (11) were examined for cytotoxicity in cell lines (L1210 and HTB-129) and for antimalarial activity in Plasmodium falciparum strains (D10, 3D7, and K1, a chloroquine-resistant strain). In general, the compounds were nontoxic in the human cell line tested (HTB-129), and compounds 4, 7, and 9 showed moderate antimalarial activity in one or more of the P. falciparum strains.

Synthesis and characterization of dual function vanadyl, gallium and indium curcumin complexes for medicinal applications

Novel bis[4-hydroxy-3-methoxyphenyl]-1,6-heptadiene-3,5-dione (curcumin) complexes with the formula, ML(3), where M is Ga(III) or In(III), or of the formula, ML(2) where M is [VO](2+), have been synthesized and characterized by mass spectrometry, infrared and absorption spectroscopies, and elemental analysis. A new ligand, bis[4-acetyl-3-hydroxyphenyl]-1,6-heptadiene-3,5-dione (diacetylbisdemethoxycurcumin, DABC) was similarly characterized; an X-ray structure analysis was performed. Vanadyl complexes tested in an acute i.p. testing protocol in STZ-diabetic rats showed a lack of insulin enhancing potential. Vanadyl complexes were, however, more cytotoxic than were the ligands alone in standard MTT (3-[4,5-dimethylthiazole-2-yl]ate, -2,5-diphenyl-tetrazolium bromide) cytotoxicity testing, using mouse lymphoma cells. With the exception of DABC, that was not different from VO(DABC)(2), the complexes were not significantly different from one another, with IC(50) values in the 5-10 microM range. Gallium and indium curcumin complexes had IC(50) values in the same 5-10 microM range; whereas Ga(DAC)(3) and In(DAC)(3) (where DAC=diacetylcurcumin) were much less cytotoxic (IC(50)=20-30 microM). Antioxidant capacity was decreased in VO(DAC)(2), Ga(DAC)(3), and In(DAC)(3), compared to vanadyl, gallium and indium curcumin, corroborating the importance of curcumin's free phenolic OH groups for scavenging oxidants, and correlated with reduced cytotoxic potential.

Complementary inhibition of synoviocyte, smooth muscle cell or mouse lymphoma cell proliferation by a vanadyl curcumin complex compared to curcumin alone

A novel vanadyl curcumin complex (VO(cur)2) has been synthesized and and its physicochemical properties characterized. Biological characterization included in vitro testing for anti-rheumatic activity in synoviocytes, angiogenesis inhibition in smooth muscle cells and anti-cancer potential in mouse lymphoma cells; as well as in vivo testing for hypoglycemic activity by oral gavage in streptozotocin (STZ)-diabetic rats. VO(cur)2 was more effective as an anti-cancer agent, compared to uncomplexed curcumin or vanadyl ion alone, was more than twice as effective as curcumin alone as an anti-arthritic agent, and was more than four times as effective as curcumin alone in inhibiting smooth muscle cell proliferation. In both acute and chronic screening tests, VO(cur)2 was ineffective as an insulin mimetic agent; however, it also proved to be exceptionally non-toxic, with no evidence of negative symptomatology during a month-long treatment period, at doses up to and including 2.0 mmol kg(-1) day(-1).

Arsenic methylation by micro-organisms isolated from sheepskin bedding materials

Sudden infant death syndrome (SIDS) has been associated with the volatilization of arsenic, antimony or phosphorus compounds from infants' bedding material by micro-organisms, the so-called 'toxic gas hypothesis'. The volatilization of arsenic by aerobic micro-organisms isolated from new sheepskin bedding material, as well as on material used by a healthy infant and by an infant who perished of SIDS, was examined. Three fungi were isolated from a piece of sheepskin bedding material on which an infant perished of SIDS, which methylated arsenic to form trimethylarsenic(V) species, precursors to volatile trimethylarsine. These three fungi were identified as Scopulariopsis koningii, Fomitopsis pinicola and Penicillium gladioli by their 26S-ribosomal RNA polymerase chain reaction products. These fungi were not previously known to methylate arsenic. The volatilization of arsenic by these three fungi was then examined. Only P. gladioli volatilized arsenic and only under conditions such that the production of sufficient trimethylarsine to be acutely toxic to an infant is unlikely. S. brevicaulis grew on the sheepskin bedding material and evolved a trace amount of trimethylarsine. Known human pathogens such as Mycobacterium neoaurum and Acinetobacter junii were isolated from used bedding.