Comorbidities and survival of multiple myeloma patients diagnosed in Finland between 2000 and 2021.

Advances in treatment have improved the survival of multiple myeloma (MM) patients, but the disease remains incurable. Here, in this nationwide retrospective real-world evidence (RWE) study, we report the patient characteristics, incidence, overall survival outcomes, comorbidities, and healthcare resource utilization (HCRU) of all adult MM patients diagnosed between 2000 and 2021 in Finland. A total of 7070 MM patients and their 21,210 age-, sex- and region-matched controls were included in the analysis. The average MM incidence doubled from 4.11 to 8.33 per 100,000 people during the follow-up. The average age-standardized incidence also showed a significant increase over time (2.51 in 2000 to 3.53 in 2021). An increase in incidence was particularly seen in older population, indicative of improved diagnosis praxis. The median overall survival (mOS) of the MM patients and their matched controls was 3.6 and 15.6 years, respectively. The mOS of all MM patients increased significantly from 2.8 years (2000-2004) to 4.4 years (2017-2021) during the follow-up period. Distinctively, in patients who received autologous stem cell transplantation (ASCT), the mOS was 9.2 years, while in patients who did not receive ASCT, the mOS was only 2.7 years. MM patients showed more comorbidities at index and increased HCRU than their matched controls. The longer median survival and decreased risk of death indicate improved treatment outcomes in MM patients in Finland.

Real-world results of first-line immunotherapy or targeted therapy for metastatic melanoma in Finland: a cohort study.

Aim: First-line (1L) immunotherapy has yielded superior overall survival (OS) in metastatic melanoma (MM) but some patients are ineligible for immunotherapy or need rapid response with 1L targeted therapy (TT).Materials & methods: Retrospective cohort study of real-world patients treated with 1L immunotherapy (144 BRAF wild type, 85 BRAF-mutated) or 1L TT (143 BRAF-mutated) for MM in Finland during 2014-2021.Results: Baseline brain metastases, liver metastases and elevated LDH were less common, 2-year OS rates were higher (60.3-63.5% vs. 33.8%) and more patients were alive without the next-line treatment (38.0-43.8% vs. 23.3%) in patients with 1L immunotherapy.Conclusion: Real-world patients with 1L immunotherapy for MM had favorable baseline characteristics and better treatment outcomes than observed in patients with 1L TT.

Real-world results of immunotherapy or targeted therapy as the first treatment option for metastatic melanoma in Finland: During the last ten years, immunotherapy and targeted therapy have improved the survival of patients with metastatic melanoma. We have studied 372 patients who had received immunotherapy or targeted therapy as the first treatment option for metastatic melanoma in Finland during 2014­2021. We found that the patients treated with immunotherapy had smaller disease burden and less commonly liver and brain metastases than the patients treated with targeted therapy. This could partly explain longer time to next treatment and longer survival achieved with immunotherapy. Over 40% of all patients received next treatment after the first treatment failed to keep their disease under control. These patients need urgently new treatment options.

Altered SOD1 maturation and post-translational modification in amyotrophic lateral sclerosis spinal cord.

Aberrant self-assembly and toxicity of wild-type and mutant superoxide dismutase 1 (SOD1) has been widely examined in silico, in vitro and in transgenic animal models of amyotrophic lateral sclerosis. Detailed examination of the protein in disease-affected tissues from amyotrophic lateral sclerosis patients, however, remains scarce. We used histological, biochemical and analytical techniques to profile alterations to SOD1 protein deposition, subcellular localization, maturation and post-translational modification in post-mortem spinal cord tissues from amyotrophic lateral sclerosis cases and controls. Tissues were dissected into ventral and dorsal spinal cord grey matter to assess the specificity of alterations within regions of motor neuron degeneration. We provide evidence of the mislocalization and accumulation of structurally disordered, immature SOD1 protein conformers in spinal cord motor neurons of SOD1-linked and non-SOD1-linked familial amyotrophic lateral sclerosis cases, and sporadic amyotrophic lateral sclerosis cases, compared with control motor neurons. These changes were collectively associated with instability and mismetallation of enzymatically active SOD1 dimers, as well as alterations to SOD1 post-translational modifications and molecular chaperones governing SOD1 maturation. Atypical changes to SOD1 protein were largely restricted to regions of neurodegeneration in amyotrophic lateral sclerosis cases, and clearly differentiated all forms of amyotrophic lateral sclerosis from controls. Substantial heterogeneity in the presence of these changes was also observed between amyotrophic lateral sclerosis cases. Our data demonstrate that varying forms of SOD1 proteinopathy are a common feature of all forms of amyotrophic lateral sclerosis, and support the presence of one or more convergent biochemical pathways leading to SOD1 proteinopathy in amyotrophic lateral sclerosis. Most of these alterations are specific to regions of neurodegeneration, and may therefore constitute valid targets for therapeutic development.

Comorbidity characteristics of multiple myeloma patients diagnosed in Finland 2005-2016.

Multiple myeloma (MM) patients are predominantly elderly with comorbidities that have an impact on patient mortality and treatment decisions. We previously reported the patient characteristics and overall survival outcomes of the Finnish MM cohort diagnosed between 2005 and 2016 in a nationwide retrospective registry study comprising 3,851 adults. Here, we report detailed comorbidity characteristics for this real-world Finnish MM population at cohort entry and during follow-up. Data on diagnoses and causes of death were obtained from Finnish healthcare data registries and interrogated using various multistate time-to-event models. In the year preceding MM diagnosis, comorbidities (as per Charlson Comorbidity Index definition) were recorded in 38.0% of the cohort, of which 27.9% presented with pre-existing cardiovascular disease (CVD) and 4.8% had suffered a major adverse cardiac event (MACE). At 2 years post-MM diagnosis, cumulative incidence for CVD and MACE more than doubled to 57.1% and 11.4%, respectively, and only 31.9% of the cohort remained CVD-free. Prevalent secondary malignancies were recorded in 16.8% of the patient population at MM diagnosis, with cumulative incidence increasing steadily to 27.5% at 2 years and 33% at 5 years post-diagnosis. The main cause of mortality attributed to MM, CVD, secondary malignancy, or other causes remained stable throughout the follow-up, at an average of 74.2%, 9.4%, 9.8%, and 6.5%, respectively. Prevalence of CVDs and secondary malignancies is high in Finnish patients at MM diagnosis, with older male patients suffering from higher MACE and mortality risk. Proper recording and management of comorbidities alongside novel treatments remain crucial for optimal MM management.

SLN124, a GalNac-siRNA targeting transmembrane serine protease 6, in combination with deferiprone therapy reduces ineffective erythropoiesis and hepatic iron-overload in a mouse model of ß-thalassaemia.

Beta-thalassaemia is an inherited blood disorder characterised by ineffective erythropoiesis and anaemia. Consequently, hepcidin expression is reduced resulting in increased iron absorption and primary iron overload. Hepcidin is under the negative control of transmembrane serine protease 6 (TMPRSS6) via cleavage of haemojuvelin (HJV), a co-receptor for the bone morphogenetic protein (BMP)-mothers against decapentaplegic homologue (SMAD) signalling pathway. Considering the central role of the TMPRSS6/HJV/hepcidin axis in iron homeostasis, the inhibition of TMPRSS6 expression represents a promising therapeutic strategy to increase hepcidin production and ameliorate anaemia and iron overload in ß-thalassaemia. In the present study, we investigated a small interfering RNA (siRNA) conjugate optimised for hepatic targeting of Tmprss6 (SLN124) in ß-thalassaemia mice (Hbbth3/+ ). Two subcutaneous injections of SLN124 (3 mg/kg) were sufficient to normalise hepcidin expression and reduce anaemia. We also observed a significant improvement in erythroid maturation, which was associated with a significant reduction in splenomegaly. Treatment with the iron chelator, deferiprone (DFP), did not impact any of the erythroid parameters. However, the combination of SLN124 with DFP was more effective in reducing hepatic iron overload than either treatment alone. Collectively, we show that the combination therapy can ameliorate several disease symptoms associated with chronic anaemia and iron overload, and therefore represents a promising pharmacological modality for the treatment of ß-thalassaemia and related disorders.

Regular Physical Exercise Modulates Iron Homeostasis in the 5xFAD Mouse Model of Alzheimer's Disease.

Dysregulation of brain iron metabolism is one of the pathological features of aging and Alzheimer's disease (AD), a neurodegenerative disease characterized by progressive memory loss and cognitive impairment. While physical inactivity is one of the risk factors for AD and regular exercise improves cognitive function and reduces pathology associated with AD, the underlying mechanisms remain unclear. The purpose of the study is to explore the effect of regular physical exercise on modulation of iron homeostasis in the brain and periphery of the 5xFAD mouse model of AD. By using inductively coupled plasma mass spectrometry and a variety of biochemical techniques, we measured total iron content and level of proteins essential in iron homeostasis in the brain and skeletal muscles of sedentary and exercised mice. Long-term voluntary running induced redistribution of iron resulted in altered iron metabolism and trafficking in the brain and increased iron content in skeletal muscle. Exercise reduced levels of cortical hepcidin, a key regulator of iron homeostasis, coupled with interleukin-6 (IL-6) decrease in cortex and plasma. We propose that regular exercise induces a reduction of hepcidin in the brain, possibly via the IL-6/STAT3/JAK1 pathway. These findings indicate that regular exercise modulates iron homeostasis in both wild-type and AD mice.

Potential Diagnostic Imaging of Alzheimer's Disease with Copper-64 Complexes That Bind to Amyloid-ß Plaques.

Amyloid-ß plaques, consisting of aggregated amyloid-ß peptides, are one of the pathological hallmarks of Alzheimer's disease. Copper complexes formed using positron-emitting copper radionuclides that cross the blood-brain barrier and bind to specific molecular targets offer the possibility of noninvasive diagnostic imaging using positron emission tomography. New thiosemicarbazone-pyridylhydrazone based ligands that incorporate pyridyl-benzofuran functional groups designed to bind amyloid-ß plaques have been synthesized. The ligands form stable complexes with copper(II) ( Kd = 10-18 M) and can be radiolabeled with copper-64 at room temperature. Subtle changes to the periphery of the ligand backbone alter the metabolic stability of the complexes in mouse and human liver microsomes, and influenced the ability of the complexes to cross the blood-brain barrier in mice. A lead complex was selected based on possessing the best metabolic stability and brain uptake in mice. Synthesis of this lead complex with isotopically enriched copper-65 allowed us to show that the complex bound to amyloid-ß plaques present in post-mortem human brain tissue using laser ablation-inductively coupled plasma-mass spectrometry. This work provides insight into strategies to target metal complexes to amyloid-ß plaques, and how small modifications to ligands can dramatically alter the metabolic stability of metal complexes as well as their ability to cross the blood-brain barrier.

A versatile quantitative microdroplet elemental imaging method optimised for integration in biochemical workflows for low-volume samples.

Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis of µ-droplets is becoming an attractive alternative for detecting and quantifying elements in biological samples. With minimal sample preparation required and detection limits comparable to solution nebulisation ICP-MS, µ-droplets have substantial advantages over traditional elemental detection, particularly for low volumes, such as aliquots taken from samples required for multiple independent biochemical assays, or fluids and tissues where elements of interest exist at native concentrations not suited to the necessary dilution steps required for solution nebulisation ICP-MS. However, the characteristics of µ-droplet residue deposition are heavily dependent on the matrix, and potential effects on signal suppression or enhancement have not been fully characterised. We present a validated and flexible high-throughput method for quantification of elements in µ-droplets using LA-ICP-MS imaging and matrix-matched external calibrants. Imaging the entire µ-droplet area removes analytical uncertainty arising from the often-heterogenous distribution when compared to radial or bisecting line scans that capture only a small portion of the droplet residue. We examined the effects of common matrices found in a standard biochemistry workflow, including native protein and salt contents, as well as reagents used in typical preparation steps for concurrent biochemical assays, such as total protein quantification and enzyme activity assays. We found that matrix composition results in systemic, concentration-dependent signal enhancement and suppression for carbon, whereas high sodium content has a specific space-charge-like suppression effect on high masses. We confirmed the accuracy of our method using both a certified serum standard (Seronorm™ L1) and independent measurements of analysed samples by solution nebulisation ICP-MS, then tested the specificity and reproducibility by examining spinal cord tissue homogenates from SOD1-G93A transgenic mice with a known molecular phenotype of increased copper- and zinc-binding superoxide dismutase-1 expression and altered copper-to-zinc stoichiometry. The method presented is rapid and transferable to multiple other biological matrices and allows high-throughput analysis of low-volume samples with sensitivity comparable to standard solution nebulisation ICP-MS protocols. Graphical Abstract ᅟ.

Stress-induced upregulation of VLDL receptor alters Wnt-signaling in neurons.

Lipoprotein receptor family members hold multiple roles in the brain, and alterations in lipoprotein receptor expression and function are implicated in neuronal stress, developmental disorders and neurodegenerative diseases, such as Alzheimer's disease. Berberine (BBR), a nutraceutical shown to have both neuroprotective and neurotoxic properties, is suggested to regulate lipoprotein receptor expression. We show that subtoxic concentration of BBR regulates neuronal lipoprotein receptor expression in a receptor- and time-dependent fashion in cerebellar granule neurons (CGN). Similarly to BBR, subtoxic concentrations of neuronal stressors cobalt chloride, thapsigargin and rotenone increased very-low-density lipoprotein receptor (VLDLR) mRNA and protein expression in CGN suggesting a conserved pathway for stress-induced upregulation of VLDLR in neurons. We also show that VLDLR upregulation is accompanied by transiently increased stabilization of hypoxia-induced factor 1 alpha (HIF-1α) and decreased ß-catenin levels affecting the Wnt pathway through GSK3ß phosphorylation, a crucial player in neurodegenerative processes. Our results indicate that neuronal stress differentially regulates lipoprotein receptor expression in neurons, with VLDLR upregulation as a common element as a modulator of neuronal Wnt signaling.

Crystal Structure of an Engineered LRRTM2 Synaptic Adhesion Molecule and a Model for Neurexin Binding.

Synaptic adhesion molecules are key components in development of the brain, and in the formation of neuronal circuits, as they are central in the assembly and maturation of chemical synapses. Several families of neuronal adhesion molecules have been identified such as the neuronal cell adhesion molecules, neurexins and neuroligins, and in particular recently several leucine-rich repeat proteins, e.g., Netrin G-ligands, SLITRKs, and LRRTMs. The LRRTMs form a family of four proteins. They have been implicated in excitatory glutamatergic synapse function and were specifically characterized as ligands for neurexins in excitatory synapse formation and maintenance. In addition, LRRTM3 and LRRTM4 have been found to be ligands for heparan sulfate proteoglycans, including glypican. We report here the crystal structure of a thermostabilized mouse LRRTM2, with a Tm 30 °C higher than that of the wild-type protein. We localized the neurexin binding site to the concave surface based on protein engineering, sequence conservation, and prior information about the interaction of the ligand with neurexins, which allowed us to propose a tentative model for the LRRTM-neurexin interaction complex. We also determined affinities of the thermostabilized LRRTM2 and wild-type LRRTM1 and LRRTM2 for neurexin-ß1 with and without Ca(2+). Cell culture studies and binding experiments show that the engineered protein is functional and capable of forming synapselike contacts. The structural and functional data presented here provide the first structure of an LRRTM protein and allow us to propose a model for the molecular mechanism of LRRTM function in the synaptic adhesion.

Trends in clinical characteristics, medication use, and glycemic control in insulin-treated patients with type 1 and type 2 diabetes in Finland in 2012-2019: Nationwide real-world evidence study.

AIMS: To describe the clinical characteristics and medication purchases of insulin-treated adults in Finland at index (January 1, 2012 or first insulin purchase) and December 31, 2019. Additionally, to describe basal insulin (BI) treatment patterns and associated changes in hemoglobin A1c (HbA1c) values. MATERIALS AND METHODS: In this descriptive study using nationwide registries, we included adults with at least two reimbursed insulin purchases within 12 months of the first purchase between January 1, 2012 and December 31, 2019. We formed four study groups: type 1 diabetes (T1D) and type 2 diabetes (T2D)-diagnosed people who were further divided into prevalent or naïve users (start of insulin use before or after January 1, 2012). Insulin treatment patterns were estimated from medication purchase data and glycemic control from HbA1c results. RESULTS: Out of 145 020 people included, 34 359 had T1D and 110 661 T2D. By 2019, in parallel with the adaptation of new noninsulin medications, second-generation basal insulin (BI) analogues were adopted by 45.9% and 21.1% of prevalent T1D and T2D users. At index, HbA1c target (≤53 mmol/mol) was reached by 17% and 35% of T2D naïve and prevalent users, respectively, and by 17% of T1D prevalent users. At study end, the target was reached respectively by 41%, 34%, and 22% of insulin users. Insulin initiation improved and discontinuation worsened glycemic control in T2D, with lesser effects seen after treatment gaps or switches between BIs. CONCLUSIONS: Our study showed that glycemic control in insulin users has remained stable or improved between 2012 and 2019 despite aging population and in parallel with introduction of new treatment options, providing valuable insight into Finnish national diabetes care.

Evidence for disrupted copper availability in human spinal cord supports CuII(atsm) as a treatment option for sporadic cases of ALS.

The copper compound CuII(atsm) has progressed to phase 2/3 testing for treatment of the neurodegenerative disease amyotrophic lateral sclerosis (ALS). CuII(atsm) is neuroprotective in mutant SOD1 mouse models of ALS where its activity is ascribed in part to improving availability of essential copper. However, SOD1 mutations cause only ~ 2% of ALS cases and therapeutic relevance of copper availability in sporadic ALS is unresolved. Herein we assessed spinal cord tissue from human cases of sporadic ALS for copper-related changes. We found that when compared to control cases the natural distribution of spinal cord copper was disrupted in sporadic ALS. A standout feature was decreased copper levels in the ventral grey matter, the primary anatomical site of neuronal loss in ALS. Altered expression of genes involved in copper handling indicated disrupted copper availability, and this was evident in decreased copper-dependent ferroxidase activity despite increased abundance of the ferroxidases ceruloplasmin and hephaestin. Mice expressing mutant SOD1 recapitulate salient features of ALS and the unsatiated requirement for copper in these mice is a biochemical target for CuII(atsm). Our results from human spinal cord indicate a therapeutic mechanism of action for CuII(atsm) involving copper availability may also be pertinent to sporadic cases of ALS.

Evidence for decreased copper associated with demyelination in the corpus callosum of cuprizone-treated mice.

Demyelination within the central nervous system (CNS) is a significant feature of debilitating neurological diseases such as multiple sclerosis and administering the copper-selective chelatorcuprizone to mice is widely used to model demyelination in vivo. Conspicuous demyelination within the corpus callosum is generally attributed to cuprizone's ability to restrict copper availability in this vulnerable brain region. However, the small number of studies that have assessed copper in brain tissue from cuprizone-treated mice have produced seemingly conflicting outcomes, leaving the role of CNS copper availability in demyelination unresolved. Herein we describe our assessment of copper concentrations in brain samples from mice treated with cuprizone for 40 d. Importantly, we applied an inductively coupled plasma mass spectrometry methodology that enabled assessment of copper partitioned into soluble and insoluble fractions within distinct brain regions, including the corpus callosum. Our results show that cuprizone-induced demyelination in the corpus callosum was associated with decreased soluble copper in this brain region. Insoluble copper in the corpus callosum was unaffected, as were pools of soluble and insoluble copper in other brain regions. Treatment with the blood-brain barrier permeant copper compound CuII(atsm) increased brain copper levels and this was most pronounced in the soluble fraction of the corpus callosum. This effect was associated with significant mitigation of cuprizone-induced demyelination. These results provide support for the involvement of decreased CNS copper availability in demyelination in the cuprizone model. Relevance to human demyelinating disease is discussed.

Integrated elemental analysis supports targeting copper perturbations as a therapeutic strategy in multiple sclerosis.

Multiple sclerosis (MS) is a debilitating affliction of the central nervous system (CNS) that involves demyelination of neuronal axons and neurodegeneration resulting in disability that becomes more pronounced in progressive forms of the disease. The involvement of neurodegeneration in MS underscores the need for effective neuroprotective approaches necessitating identification of new therapeutic targets. Herein, we applied an integrated elemental analysis workflow to human MS-affected spinal cord tissue utilising multiple inductively coupled plasma-mass spectrometry methodologies. These analyses revealed shifts in atomic copper as a notable aspect of disease. Complementary gene expression and biochemical analyses demonstrated that changes in copper levels coincided with altered expression of copper handling genes and downstream functionality of cuproenzymes. Copper-related problems observed in the human MS spinal cord were largely reproduced in the experimental autoimmune encephalomyelitis (EAE) mouse model during the acute phase of disease characterised by axonal demyelination, lesion formation, and motor neuron loss. Treatment of EAE mice with the CNS-permeant copper modulating compound CuII(atsm) resulted in recovery of cuproenzyme function, improved myelination and lesion volume, and neuroprotection. These findings support targeting copper perturbations as a therapeutic strategy for MS with CuII(atsm) showing initial promise.

Microglial ferroptotic stress causes non-cell autonomous neuronal death.

BACKGROUND: Ferroptosis is a form of regulated cell death characterised by lipid peroxidation as the terminal endpoint and a requirement for iron. Although it protects against cancer and infection, ferroptosis is also implicated in causing neuronal death in degenerative diseases of the central nervous system (CNS). The precise role for ferroptosis in causing neuronal death is yet to be fully resolved. METHODS: To elucidate the role of ferroptosis in neuronal death we utilised co-culture and conditioned medium transfer experiments involving microglia, astrocytes and neurones. We ratified clinical significance of our cell culture findings via assessment of human CNS tissue from cases of the fatal, paralysing neurodegenerative condition of amyotrophic lateral sclerosis (ALS). We utilised the SOD1G37R mouse model of ALS and a CNS-permeant ferroptosis inhibitor to verify pharmacological significance in vivo. RESULTS: We found that sublethal ferroptotic stress selectively affecting microglia triggers an inflammatory cascade that results in non-cell autonomous neuronal death. Central to this cascade is the conversion of astrocytes to a neurotoxic state. We show that spinal cord tissue from human cases of ALS exhibits a signature of ferroptosis that encompasses atomic, molecular and biochemical features. Further, we show the molecular correlation between ferroptosis and neurotoxic astrocytes evident in human ALS-affected spinal cord is recapitulated in the SOD1G37R mouse model where treatment with a CNS-permeant ferroptosis inhibitor, CuII(atsm), ameliorated these markers and was neuroprotective. CONCLUSIONS: By showing that microglia responding to sublethal ferroptotic stress culminates in non-cell autonomous neuronal death, our results implicate microglial ferroptotic stress as a rectifiable cause of neuronal death in neurodegenerative disease. As ferroptosis is currently primarily regarded as an intrinsic cell death phenomenon, these results introduce an entirely new pathophysiological role for ferroptosis in disease.

γ-Aminobutyric acid type A (GABAA) receptor activation modulates tau phosphorylation.

Abnormal phosphorylation and aggregation of the microtubule-associated protein Tau are hallmarks of various neurodegenerative diseases, such as Alzheimer disease. Molecular mechanisms that regulate Tau phosphorylation are complex and currently incompletely understood. We have developed a novel live cell reporter system based on protein-fragment complementation assay to study dynamic changes in Tau phosphorylation status. In this assay, fusion proteins of Tau and Pin1 (peptidyl-prolyl cis-trans-isomerase 1) carrying complementary fragments of a luciferase protein serve as a sensor of altered protein-protein interaction between Tau and Pin1, a critical regulator of Tau dephosphorylation at several disease-associated proline-directed phosphorylation sites. Using this system, we identified several structurally distinct GABA(A) receptor modulators as novel regulators of Tau phosphorylation in a chemical library screen. GABA(A) receptor activation promoted specific phosphorylation of Tau at the AT8 epitope (Ser-199/Ser-202/Thr-205) in cultures of mature cortical neurons. Increased Tau phosphorylation by GABA(A) receptor activity was associated with reduced Tau binding to protein phosphatase 2A and was dependent on Cdk5 but not GSK3ß kinase activity.

PCSK9 regulates neuronal apoptosis by adjusting ApoER2 levels and signaling.

The secreted protease proprotein convertase subtilisin/kexin type 9 (PCSK9) binds to low-density lipid (LDL) receptor family members LDLR, very low density lipoprotein receptor (VLDLR) and apolipoprotein receptor 2 (ApoER2), and promotes their degradation in intracellular acidic compartments. In the liver, LDLR is a major controller of blood LDL levels, whereas VLDLR and ApoER2 in the brain mediate Reelin signaling, a critical pathway for proper development of the nervous system. Expression level of PCSK9 in the brain is highest in the cerebellum during perinatal development, but is also increased in the adult brain after ischemia. The mechanism of PCSK9 function and its involvement in neuronal apoptosis is poorly understood. We show here that RNAi-mediated knockdown of PCSK9 significantly reduced the death of potassium-deprived cerebellar granule neurons (CGN), as shown by reduced levels of nuclear phosphorylated c-Jun and activated caspase-3, as well as condensed apoptotic nuclei. ApoER2 protein levels were increased in PCSK9 RNAi cells. Knockdown of ApoER2 but not of VLDLR was sufficient to reverse the protection provided by PCSK9 RNAi, suggesting that proapoptotic signaling of PCSK9 is mediated by altered ApoER2 function. Pharmacological inhibition of signaling pathways associated with lipoprotein receptors suggested that PCSK9 regulates neuronal apoptosis independently of NMDA receptor function but in concert with ERK and JNK signaling pathways. PCSK9 RNAi also reduced staurosporine-induced CGN apoptosis and axonal degeneration in the nerve growth factor-deprived dorsal root ganglion neurons. We conclude that PCSK9 potentiates neuronal apoptosis via modulation of ApoER2 levels and related anti-apoptotic signaling pathways.

Transdermal Application of Soluble CuII(atsm) Increases Brain and Spinal Cord Uptake Compared to Gavage with an Insoluble Suspension.

CuII(atsm) is a blood-brain barrier permeant copper(II) compound that is under investigation in human clinical trials for the treatment of neurodegenerative diseases of the central nervous system (CNS). Imaging in humans by positron emission tomography shows the compound accumulates in affected regions of the CNS in patients. Most therapeutic studies to date have utilised oral administration of CuII(atsm) in an insoluble form, as either solid tablets or a liquid suspension. However, two pre-clinical studies have demonstrated disease-modifying outcomes following transdermal application of soluble CuII(atsm) prepared in dimethyl sulphoxide. Whether differences in the method of administration lead to different degrees of tissue accumulation of the compound has never been examined. Here, we compare the two methods of administration in wild-type mice by assessing changes in tissue concentrations of copper. Both administration methods resulted in elevated copper concentrations in numerous tissues, with the largest increases evident in the liver, brain and spinal cord. In all instances where treatment with CuII(atsm) resulted in elevated tissue copper, transdermal application of soluble CuII(atsm) led to higher concentrations of copper. In contrast to CuII(atsm), an equivalent dose of copper(II) chloride resulted in minimal changes to tissue copper concentrations, regardless of the administration method. Data presented herein provide quantitative insight to transdermal application of soluble CuII(atsm) as a potential alternative to oral administration of the compound in an insoluble formulation.

Iron overload and impaired iron handling contribute to the dystrophic pathology in models of Duchenne muscular dystrophy.

BACKGROUND: Oxidative stress is implicated in the pathophysiology of Duchenne muscular dystrophy (DMD, caused by mutations in the dystrophin gene), which is the most common and severe of the muscular dystrophies. To our knowledge, the distribution of iron, an important modulator of oxidative stress, has not been assessed in DMD. We tested the hypotheses that iron accumulation occurs in mouse models of DMD and that modulation of iron through the diet or chelation could modify disease severity. METHODS: We assessed iron distribution and total elemental iron using LA-ICP-MS on skeletal muscle cross-sections of 8-week-old Bl10 control mice and dystrophic mdx mice (with moderate dystrophy) and dystrophin/utrophin-null mice (dko, with severe dystrophy). In addition, mdx mice (4 weeks) were treated with either an iron chelator (deferiprone 150 mg/kg/day) or iron-enriched feed (containing 1% added iron as carbonyl iron). Immunoblotting was used to determine the abundance of iron- and mitochondria-related proteins. (Immuno)histochemical and mRNA assessments of fibrosis and inflammation were also performed. RESULTS: We observed a significant increase in total elemental iron in hindlimb muscles of dko mice (+50%, P < 0.05) and in the diaphragm of mdx mice (+80%, P < 0.05), with both tissues exhibiting severe pathology. Iron dyshomeostasis was further evidenced by an increase in the storage protein ferritin (dko: +39%, P < 0.05) and ferroportin compared with Bl10 control mice (mdx: +152% and dko: +175%, P < 0.05). Despite having features of iron overload, dystrophic muscles had lower protein expression of ALAS-1, the rate-limiting enzyme for haem synthesis (dko -44%, P < 0.05), and the haem-containing protein myoglobin (dko -54%, P < 0.05). Deferiprone treatment tended to decrease muscle iron levels in mdx mice (-30%, P < 0.1), which was associated with lower oxidative stress and fibrosis, but suppressed haem-containing proteins and mitochondrial content. Increasing iron via dietary intervention elevated total muscle iron (+25%, P < 0.05) but did not aggravate the pathology. CONCLUSIONS: Muscles from dystrophic mice have increased iron levels and dysregulated iron-related proteins that are associated with dystrophic pathology. Muscle iron levels were manipulated by iron chelation and iron enriched feed. Iron chelation reduced fibrosis and reactive oxygen species (ROS) but also suppressed haem-containing proteins and mitochondrial activity. Conversely, iron supplementation increased ferritin and haem-containing proteins but did not alter ROS, fibrosis, or mitochondrial activity. Further studies are required to investigate the contribution of impaired ferritin breakdown in the dysregulation of iron homeostasis in DMD.