Intermittent Ex Vivo Lung Perfusion in a Porcine Model for Prolonged Lung Preservation

BACKGROUND

Ex vivo lung perfusion expands the lung transplant donor pool and extends preservation time beyond cold static preservation. We hypothesized that repeated regular ex vivo lung perfusion would better maintain lung grafts.

METHODS

Ten pig lungs were randomized into 2 groups. The control underwent 16 h of cold ischemic time and 2 h of cellular ex vivo lung perfusion. The intermittent ex vivo lung perfusion group underwent cold ischemic time for 4 h, ex vivo lung perfusion (first) for 2 h, cold ischemic time for 10 h, and 2 h of ex vivo lung perfusion (second). Lungs were assessed, and transplant suitability was determined after 2 h of ex vivo lung perfusion.

RESULTS

The second ex vivo lung perfusion was significantly associated with better oxygenation, limited extravascular water, higher adenosine triphosphate, reduced intraalveolar edema, and well-preserved mitochondria compared with the control, despite proinflammatory cytokine elevation. No significant difference was observed in the first and second perfusion regarding oxygenation and adenosine triphosphate, whereas the second was associated with lower dynamic compliance and higher extravascular lung water than the first. Transplant suitability was 100% for the first and 60% for the second ex vivo lung perfusion, and 0% for the control.

CONCLUSIONS

The second ex vivo lung perfusion had a slight deterioration in graft function compared to the first. Intermittent ex vivo lung perfusion created a better condition for lung grafts than cold static preservation, despite cytokine elevation. These results suggested that intermittent ex vivo lung perfusion may help prolong lung preservation.

Intraneuronal β-amyloid impaired mitochondrial proteostasis through the impact on LONP1

Mitochondrial dysfunction plays a critical role in the pathogenesis of Alzheimer's disease (AD). Mitochondrial proteostasis regulated by chaperones and proteases in each compartment of mitochondria is critical for mitochondrial function, and it is suspected that mitochondrial proteostasis deficits may be involved in mitochondrial dysfunction in AD. In this study, we identified LONP1, an ATP-dependent protease in the matrix, as a top Aβ42 interacting mitochondrial protein through an unbiased screening and found significantly decreased LONP1 expression and extensive mitochondrial proteostasis deficits in AD experimental models both in vitro and in vivo, as well as in the brain of AD patients. Impaired METTL3-m6A signaling contributed at least in part to Aβ42-induced LONP1 reduction. Moreover, Aβ42 interaction with LONP1 impaired the assembly and protease activity of LONP1 both in vitro and in vivo. Importantly, LONP1 knockdown caused mitochondrial proteostasis deficits and dysfunction in neurons, while restored expression of LONP1 in neurons expressing intracellular Aβ and in the brain of CRND8 APP transgenic mice rescued Aβ-induced mitochondrial deficits and cognitive deficits. These results demonstrated a critical role of LONP1 in disturbed mitochondrial proteostasis and mitochondrial dysfunction in AD and revealed a mechanism underlying intracellular Aβ42-induced mitochondrial toxicity through its impact on LONP1 and mitochondrial proteostasis.

Bezafibrate confers neuroprotection in the 5xFAD mouse model of Alzheimer's disease

Mitochondrial dysfunction plays an important role in the pathogenesis of Alzheimer's disease (AD), the most common neurodegenerative disease. Prior studies suggested impaired mitochondrial biogenesis likely contributes to mitochondrial dysfunction in AD. Bezafibrate, a peroxisome proliferator-activated receptor (PPAR) pan-agonist, has been shown to enhance mitochondrial biogenesis and increase oxidative phosphorylation capacity. In the present study, we investigated whether bezafibrate could rescue mitochondrial dysfunction and other AD-related deficits in 5xFAD mice. Bezafibrate was well tolerated by 5xFAD mice. Indeed, it rescued the expression of key mitochondrial proteins as well as mitochondrial dynamics and function in the brain of 5xFAD mice. Importantly, bezafibrate treatment led to significant improvement of cognitive/memory function in 5xFAD mice accompanied by alleviation of amyloid pathology and neuronal loss as well as reduced oxidative stress and neuroinflammation. Overall, this study suggests that bezafibrate improves mitochondrial function, mitigates neuroinflammation and improves cognitive functions in 5xFAD mice, thus supporting the notion that enhancing mitochondrial biogenesis/function is a promising therapeutic strategy for AD.

Fluorescent Nanoparticle Uptake by Myzocytosis and Endocytosis in Colpodella sp. ATCC 50594

Colpodella sp. (ATCC 50594) is a free-living biflagellate predator closely related to pathogenic Apicomplexa such as Plasmodium, Cryptosporidium and Toxoplasma gondii. Colpodella sp. (ATCC 50594) obtain nutrients by preying on Parabodo caudatus using myzocytosis. The organization of the myzocytic apparatus and the mechanism of nutrient uptake into the posterior food vacuole of Colpodella species is unknown. In this study, we investigated myzocytosis using light and transmission electron microscopy. We investigated the uptake of 40 nm and 100 nm fluorescent nanoparticles and E. coli BioParticles by Colpodella sp. (ATCC 50594) in a diprotist culture. Transmission electron microscopy was used to investigate the morphology of the tubular tether formed during myzocytosis. E. coli BioParticles were taken up by P. caudatus but not by Colpodella sp. (ATCC 50594). Both protists took up the 100 nm and 40 nm beads, which were observed distributed in the cytoplasm of free unattached Colpodella sp. (ATCC 50594) trophozoites, and also in feeding Colpodella sp. (ATCC 50594) trophozoites and in the pre-cysts. Fragments of the nucleus and kinetoplast of P. caudatus and the nanoparticles were identified in the tubular tether being aspirated into the posterior food vacuole of Colpodella sp. (ATCC 50594). Unattached Colpodella sp. (ATCC 50594) endocytose nutrients from the culture medium independently from myzocytosis. The mechanisms of myzocytosis and endocytosis among Colpodella species may provide important insights into nutrient uptake among the pathogenic apicomplexans.

Damaged mitochondria coincide with presynaptic vesicle loss and abnormalities in alzheimer's disease brain

Loss of synapses is the most robust pathological correlate of Alzheimer's disease (AD)-associated cognitive deficits, although the underlying mechanism remains incompletely understood. Synaptic terminals have abundant mitochondria which play an indispensable role in synaptic function through ATP provision and calcium buffering. Mitochondrial dysfunction is an early and prominent feature in AD which could contribute to synaptic deficits. Here, using electron microscopy, we examined synapses with a focus on mitochondrial deficits in presynaptic axonal terminals and dendritic spines in cortical biopsy samples from clinically diagnosed AD and age-matched non-AD control patients. Synaptic vesicle density within the presynaptic axon terminals was significantly decreased in AD cases which appeared largely due to significantly decreased reserve pool, but there were significantly more presynaptic axons containing enlarged synaptic vesicles or dense core vesicles in AD. Importantly, there was reduced number of mitochondria along with significantly increased damaged mitochondria in the presynapse of AD which correlated with changes in SV density. Mitochondria in the post-synaptic dendritic spines were also enlarged and damaged in the AD biopsy samples. This study provided evidence of presynaptic vesicle loss as synaptic deficits in AD and suggested that mitochondrial dysfunction in both pre- and post-synaptic compartments contribute to synaptic deficits in AD.

α-Crystallin chaperone mimetic drugs inhibit lens γ-crystallin aggregation: potential role for cataract prevention

Γ-Crystallins play a major role in age-related lens transparency. Their destabilization by mutations and physical chemical insults are associated with cataract formation. Therefore, drugs that increase their stability should have anticataract properties. To this end, we screened 2560 Federal Drug Agency–approved drugs and natural compounds for their ability to suppress or worsen H₂O₂ and/or heat-mediated aggregation of bovine γ-crystallins. The top two drugs, closantel (C), an antihelminthic drug, and gambogic acid (G), a xanthonoid, attenuated thermal-induced protein unfolding and aggregation as shown by turbidimetry fluorescence spectroscopy dynamic light scattering and electron microscopy of human or mouse recombinant crystallins. Furthermore, binding studies using fluorescence inhibition and hydrophobic pocket–binding molecule bis-8-anilino-1-naphthalene sulfonic acid revealed static binding of C and G to hydrophobic sites with medium-to-low affinity. Molecular docking to HγD and other γ-crystallins revealed two binding sites, one in the “NC pocket” (residues 50–150) of HγD and one spanning the “NC tail” (residues 56–61 to 168–174 in the C-terminal domain). Multiple binding sites overlap with those of the protective mini αA-crystallin chaperone MAC peptide. Mechanistic studies using bis-8-anilino-1-naphthalene sulfonic acid as a proxy drug showed that it bound to MAC sites, improved T_m of both H₂O₂ oxidized and native human gamma D, and suppressed turbidity of oxidized HγD, most likely by trapping exposed hydrophobic sites. The extent to which these drugs act as α-crystallin mimetics and reduce cataract progression remains to be demonstrated. This study provides initial insights into binding properties of C and G to γ-crystallins.

Mitochondrial uncoupling attenuates sarcopenic obesity by enhancing skeletal muscle mitophagy and quality control

BACKGROUND

Sarcopenic obesity is a highly prevalent disease with poor survival and ineffective medical interventions. Mitochondrial dysfunction is purported to be central in the pathogenesis of sarcopenic obesity by impairing both organelle biogenesis and quality control. We have previously identified that a mitochondrial-targeted furazano[3,4-b]pyrazine named BAM15 is orally available and selectively lowers respiratory coupling efficiency and protects against diet-induced obesity in mice. Here, we tested the hypothesis that mitochondrial uncoupling simultaneously attenuates loss of muscle function and weight gain in a mouse model of sarcopenic obesity.

METHODS

Eighty-week-old male C57BL/6J mice with obesity were randomized to 10 weeks of high fat diet (CTRL) or BAM15 (BAM15; 0.1% w/w in high fat diet) treatment. Body weight and food intake were measured weekly. Body composition, muscle function, energy expenditure, locomotor activity, and glucose tolerance were determined after treatment. Skeletal muscle was harvested and evaluated for histology, gene expression, protein signalling, and mitochondrial structure and function.

RESULTS

BAM15 decreased body weight (54.0 ± 2.0 vs. 42.3 ± 1.3 g, P < 0.001) which was attributable to increased energy expenditure (10.1 ± 0.1 vs. 11.3 ± 0.4 kcal/day, P < 0.001). BAM15 increased muscle mass (52.7 ± 0.4 vs. 59.4 ± 1.0%, P < 0.001), strength (91.1 ± 1.3 vs. 124.9 ± 1.2 g, P < 0.0001), and locomotor activity (347.0 ± 14.4 vs. 432.7 ± 32.0 m, P < 0.001). Improvements in physical function were mediated in part by reductions in skeletal muscle inflammation (interleukin 6 and gp130, both P < 0.05), enhanced mitochondrial function, and improved endoplasmic reticulum homeostasis. Specifically, BAM15 activated mitochondrial quality control (PINK1-ubiquitin binding and LC3II, P < 0.01), increased mitochondrial activity (citrate synthase and complex II activity, all P < 0.05), restricted endoplasmic reticulum (ER) misfolding (decreased oligomer A11 insoluble/soluble ratio, P < 0.0001) while limiting ER stress (decreased PERK signalling, P < 0.0001), apoptotic signalling (decreased cytochrome C release and Caspase-3/9 activation, all P < 0.001), and muscle protein degradation (decreased 14-kDa actin fragment insoluble/soluble ratio, P < 0.001).

CONCLUSIONS

Mitochondrial uncoupling by agents such as BAM15 may mitigate age-related decline in muscle mass and function by molecular and cellular bioenergetic adaptations that confer protection against sarcopenic obesity.

Measurements of Strong-Interaction Effects in Kaonic-Helium Isotopes at Sub-eV Precision with X-Ray Microcalorimeters

We have measured the 3d→2p transition x rays of kaonic ^{3}He and ^{4}He atoms using superconducting transition-edge-sensor microcalorimeters with an energy resolution better than 6 eV (FWHM). We determined the energies to be 6224.5±0.4(stat)±0.2(syst)  eV and 6463.7±0.3(stat)±0.1(syst)  eV, and widths to be 2.5±1.0(stat)±0.4(syst)  eV and 1.0±0.6(stat)±0.3(stat)  eV, for kaonic ^{3}He and ^{4}He, respectively. These values are nearly 10 times more precise than in previous measurements. Our results exclude the large strong-interaction shifts and widths that are suggested by a coupled-channel approach and agree with calculations based on optical-potential models.

Preparation status of missing-mass spectroscopy for 𝚵 hypernuclei with S-2S magnetic spectrometer

J-PARC E70 experiment measures the missing-mass of Ξ hypernuclei (12ΞBe) in Hadron Experimental Facility at J-PARC. We aim to reach the best missing-mass resolution of 2 MeV/c2 in FWHM with a new magnetic spectrometer S-2S. The high-resolution spectroscopy of Ξ hypernuclei will play an important role to understand the unknown ΞN interaction. The experiment will start at the beginning of 2023. This article presents the preparation status.

Translational regulation in the brain by TDP-43 phase separation

The in vivo physiological function of liquid-liquid phase separation (LLPS) that governs non-membrane-bound structures remains elusive. Among LLPS-prone proteins, TAR DNA-binding protein of 43 kD (TDP-43) is under intense investigation because of its close association with neurological disorders. Here, we generated mice expressing endogenous LLPS-deficient murine TDP-43. LLPS-deficient TDP-43 mice demonstrate impaired neuronal function and behavioral abnormalities specifically related to brain function. Brain neurons of these mice, however, did not show TDP-43 proteinopathy or neurodegeneration. Instead, the global rate of protein synthesis was found to be greatly enhanced by TDP-43 LLPS loss. Mechanistically, TDP-43 LLPS ablation increased its association with PABPC4, RPS6, RPL7, and other translational factors. The physical interactions between TDP-43 and translational factors relies on a motif, the deletion of which abolished the impact of LLPS-deficient TDP-43 on translation. Our findings show a specific physiological role for TDP-43 LLPS in the regulation of brain function and uncover an intriguing novel molecular mechanism of translational control by LLPS.

Mitochondrial Fusion Suppresses Tau Pathology-Induced Neurodegeneration and Cognitive Decline

BACKGROUND

Abnormalities of mitochondrial fission and fusion, dynamic processes known to be essential for various aspects of mitochondrial function, have repeatedly been reported to be altered in Alzheimer's disease (AD). Neurofibrillary tangles are known as a hallmark feature of AD and are commonly considered a likely cause of neurodegeneration in this devastating disease.

OBJECTIVE

To understand the pathological role of mitochondrial dynamics in the context of tauopathy.

METHODS

The widely used P301S transgenic mice of tauopathy (P301S mice) were crossed with transgenic TMFN mice with the forced expression of Mfn2 specifically in neurons to obtain double transgenic P301S/TMFN mice. Brain tissues from 11-month-old non-transgenic (NTG), TMFN, P301S, and P301S/TMFN mice were analyzed by electron microscopy, confocal microscopy, immunoblot, histological staining, and immunostaining for mitochondria, tau pathology, and tau pathology-induced neurodegeneration and gliosis. The cognitive function was assessed by the Barnes maze.

RESULTS

P301S mice exhibited mitochondrial fragmentation and a consistent decrease in Mfn2 compared to age-matched NTG mice. When P301S mice were crossed with TMFN mice (P301S/TMFN mice), neuronal loss, as well as mitochondria fragmentation were significantly attenuated. Greatly alleviated tau hyperphosphorylation, filamentous aggregates, and thioflavin-S positive tangles were also noted in P301S/TMFN mice. Furthermore, P301S/TMFN mice showed marked suppression of neuroinflammation and improved cognitive performance in contrast to P301S mice.

CONCLUSION

These in vivo findings suggest that promoted mitochondrial fusion suppresses toxic tau accumulation and associated neurodegeneration, which may protect against the progression of AD and related tauopathies.

Dynamin-related protein 1 regulates substrate oxidation in skeletal muscle by stabilizing cellular and mitochondrial calcium dynamics

Mitochondria undergo continuous cycles of fission and fusion to promote inheritance, regulate quality control, and mitigate organelle stress. More recently, this process of mitochondrial dynamics has been demonstrated to be highly sensitive to nutrient supply, ultimately conferring bioenergetic plasticity to the organelle. However, whether regulators of mitochondrial dynamics play a causative role in nutrient regulation remains unclear. In this study, we generated a cellular loss-of-function model for dynamin-related protein 1 (DRP1), the primary regulator of outer membrane mitochondrial fission. Loss of DRP1 (shDRP1) resulted in extensive ultrastructural and functional remodeling of mitochondria, characterized by pleomorphic enlargement, increased electron density of the matrix, and defective NADH and succinate oxidation. Despite increased mitochondrial size and volume, shDRP1 cells exhibited reduced cellular glucose uptake and mitochondrial fatty acid oxidation. Untargeted transcriptomic profiling revealed severe downregulation of genes required for cellular and mitochondrial calcium homeostasis, which was coupled to loss of ATP-stimulated calcium flux and impaired substrate oxidation stimulated by exogenous calcium. The insights obtained herein suggest that DRP1 regulates substrate oxidation by altering whole-cell and mitochondrial calcium dynamics. These findings are relevant to the targetability of mitochondrial fission and have clinical relevance in the identification of treatments for fission-related pathologies such as hereditary neuropathies, inborn errors in metabolism, cancer, and chronic diseases.

Lipids activate skeletal muscle mitochondrial fission and quality control networks to induce insulin resistance in humans

BACKGROUND AND AIMS

A diminution in skeletal muscle mitochondrial function due to ectopic lipid accumulation and excess nutrient intake is thought to contribute to insulin resistance and the development of type 2 diabetes. However, the functional integrity of mitochondria in insulin-resistant skeletal muscle remains highly controversial.

METHODS

19 healthy adults (age:28.4 ± 1.7 years; BMI:22.7 ± 0.3 kg/m²) received an overnight intravenous infusion of lipid (20% Intralipid) or saline followed by a hyperinsulinemic-euglycemic clamp to assess insulin sensitivity using a randomized crossover design. Skeletal muscle biopsies were obtained after the overnight lipid infusion to evaluate activation of mitochondrial dynamics proteins, ex-vivo mitochondrial membrane potential, ex-vivo oxidative phosphorylation and electron transfer capacity, and mitochondrial ultrastructure.

RESULTS

Overnight lipid infusion increased dynamin related protein 1 (DRP1) phosphorylation at serine 616 and PTEN-induced kinase 1 (PINK1) expression (P = 0.003 and P = 0.008, respectively) in skeletal muscle while reducing mitochondrial membrane potential (P = 0.042). The lipid infusion also increased mitochondrial-associated lipid droplet formation (P = 0.011), the number of dilated cristae, and the presence of autophagic vesicles without altering mitochondrial number or respiratory capacity. Additionally, lipid infusion suppressed peripheral glucose disposal (P = 0.004) and hepatic insulin sensitivity (P = 0.014).

CONCLUSIONS

These findings indicate that activation of mitochondrial fission and quality control occur early in the onset of insulin resistance in human skeletal muscle. Targeting mitochondrial dynamics and quality control represents a promising new pharmacological approach for treating insulin resistance and type 2 diabetes.

CLINICAL TRIAL REGISTRATION

NCT02697201, ClinicalTrials.gov.

Colpodella sp. (ATCC 50594) Life Cycle: Myzocytosis and Possible Links to the Origin of Intracellular Parasitism

Colpodella species are free living bi-flagellated protists that prey on algae and bodonids in a process known as myzocytosis. Colpodella species are phylogenetically related to Apicomplexa. We investigated the life cycle of Colpodella sp. (ATCC 50594) to understand the timing, duration and the transition stages of Colpodella sp. (ATCC 50594). Sam-Yellowe’s trichrome stains for light microscopy, confocal and differential interference contrast (DIC) microscopy was performed to identify cell morphology and determine cross reactivity of Plasmodium species and Toxoplasma gondii specific antibodies against Colpodella sp. (ATCC 50594) proteins. The ultrastructure of Colpodella sp. (ATCC 50594) was investigated by transmission electron microscopy (TEM). The duration of Colpodella sp. (ATCC 50594) life cycle is thirty-six hours. Colpodella sp. (ATCC 50594) were most active between 20–28 h. Myzocytosis is initiated by attachment of the Colpodella sp. (ATCC 50594) pseudo-conoid to the cell surface of Parabodo caudatus, followed by an expansion of microtubules at the attachment site and aspiration of the prey’s cytoplasmic contents. A pre-cyst formed at the conclusion of feeding differentiates into a transient or resting cyst. Both DIC and TEM microscopy identified asynchronous and asymmetric mitosis in Colpodella sp. (ATCC 50594) cysts. Knowledge of the life cycle and stages of Colpodella sp. (ATCC 50594) will provide insights into the development of intracellular parasitism among the apicomplexa.

The role of Mfn2 in the structure and function of endoplasmic reticulum-mitochondrial tethering in vivo

Mitochondria-endoplasmic reticulum contacts (MERCs) play an essential role in multiple cell physiological processes. Although Mfn2 was the first protein implicated in the formation of MERCs, there is debate as to whether it acts as a tether or antagonizer, largely based on in vitro studies. To understand the role of Mfn2 in MERCs in vivo, we characterized ultrastructural and biochemical changes of MERCs in pyramidal neurons of hippocampus in Mfn2 conditional knockout mice and in Mfn2 overexpressing mice, and found that Mfn2 ablation caused reduced close contacts, whereas Mfn2 overexpression caused increased close contacts between the endoplasmic reticulum (ER) and mitochondria in vivo. Functional studies on SH-SY5Y cells with Mfn2 knockout or overexpression demonstrating similar biochemical changes found that mitochondrial calcium uptake along with IP3R3-Grp75 interaction was decreased in Mfn2 knockout cells but increased in Mfn2 overexpressing cells. Lastly, we found Mfn2 knockout decreased and Mfn2 overexpression increased the interaction between the ER-mitochondria tethering pair of VAPB-PTPIP51. In conclusion, our study supports the notion that Mfn2 plays a critical role in ER-mitochondrial tethering and the formation of close contacts in neuronal cells in vivo.

VPS35 D620N knockin mice recapitulate cardinal features of Parkinson's disease

D620N mutation in the vacuolarproteinsorting35ortholog (VPS35) gene causes late‐onset, autosomal dominant familial Parkinson's disease (PD) and contributes to idiopathic PD. However, how D620N mutation leads to PD‐related deficits in vivo remains unclear. In the present study, we thoroughly characterized the biochemical, pathological, and behavioral changes of a VPS35 D620N knockin (KI) mouse model with chronic aging. We reported that this VPS35 D620N KI model recapitulated a spectrum of cardinal features of PD at 14 months of age which included age‐dependent progressive motor deficits, significant changes in the levels of dopamine (DA) and DA metabolites in the striatum, and robust neurodegeneration of the DA neurons in the SNpc and DA terminals in the striatum, accompanied by increased neuroinflammation, and accumulation and aggregation of α‐synuclein in DA neurons. Mechanistically, D620N mutation induced mitochondrial fragmentation and dysfunction in aged mice likely through enhanced VPS35‐DLP1 interaction and increased turnover of mitochondrial DLP1 complexes in vivo. Finally, the VPS35 D620N KI mice displayed greater susceptibility to MPTP‐mediated degeneration of nigrostriatal pathway, indicating that VPS35 D620N mutation increased vulnerability of DA neurons to environmental toxins. Overall, this VPS35 D620N KI mouse model provides a powerful tool for future disease modeling and pharmacological studies of PD. Our data support the involvement of VPS35 in the development of α‐synuclein pathology in vivo and revealed the important role of mitochondrial fragmentation/dysfunction in the pathogenesis of VPS35 D620N mutation‐associated PD in vivo.

The effect of viscoelasticity in an airway closure model

The closure of a human lung airway is modeled as a pipe coated internally with a liquid that takes into account the viscoelastic properties of mucus. For a thick enough coating, the Plateau-Rayleigh instability blocks the airway by the creation of a liquid plug, and the pre-closure phase is dominated by the Newtonian behavior of the liquid. Our previous study with a Newtonian-liquid model demonstrated that the bifrontal plug growth consequent to airway closure induces a high level of stress and stress gradients on the airway wall, which is large enough to damage the epithelial cells, causing sub-lethal or lethal responses. In this study, we explore the effect of the viscoelastic properties of mucus by means of the Oldroyd-B and FENE-CR model. Viscoelasticity is shown to be very relevant in the post-coalescence process, introducing a second peak of the wall shear stresses. This second peak is related to an elastic instability due to the presence of the polymeric extra stresses. For high-enough Weissenberg and Laplace numbers, this second shear stress peak is as severe as the first one. Consequently, a second lethal or sub-lethal response of the epithelial cells is induced.

Novel life cycle stages of Colpodella sp. (Apicomplexa) identified using Sam-Yellowe's trichrome stains and confocal and electron microscopy

Colpodella spp. are free-living flagellates closely related to the apicomplexans. Human infections by Colpodella sp. have been reported. A biflagellated trophozoite and cyst stage comprise the known life cycle stages of Colpodella sp. However, the process of encystation and excystation within the life cycle is unclear. Life cycle stages initiating human infections are unknown. We performed a detailed investigation of the life cycle of Colpodella sp. (ATCC 50594) in culture using Sam-Yellowe's trichrome stains and differential interference contrast (DIC) for light microscopy and fluorescence microscopy of Congo red-stained cells and investigated ultrastructure using transmission electron microscopy (TEM). We report previously undocumented stages of Colpodella sp. Asymmetric and asynchronous division was detected inside cysts by trichrome staining and by TEM. Odd-numbered juveniles and cysts containing more than four juvenile trophozoites were identified. Live imaging of active cultures captured the excystation and egress of juvenile trophozoites and confirmed the presence of multinucleate cysts. The ultrastructure of the multinucleate cyst is reminiscent of apicomplexan schizonts. Insights gained from the life cycle stages observed in culture allowed the construction of the life cycle of Colpodella sp. Knowledge of the life cycle will aid biochemical and molecular characterization of Colpodella sp. and help identify stages in human infections.

Oligodendroglial glycolytic stress triggers inflammasome activation and neuropathology in Alzheimer's disease

Myelin degeneration and white matter loss resulting from oligodendrocyte (OL) death are early events in Alzheimer's disease (AD) that lead to cognitive deficits; however, the underlying mechanism remains unknown. Here, we find that mature OLs in both AD patients and an AD mouse model undergo NLR family pyrin domain containing 3 (NLRP3)-dependent Gasdermin D-associated inflammatory injury, concomitant with demyelination and axonal degeneration. The mature OL-specific knockdown of dynamin-related protein 1 (Drp1; a mitochondrial fission guanosine triphosphatase) abolishes NLRP3 inflammasome activation, corrects myelin loss, and improves cognitive ability in AD mice. Drp1 hyperactivation in mature OLs induces a glycolytic defect in AD models by inhibiting hexokinase 1 (HK1; a mitochondrial enzyme that initiates glycolysis), which triggers NLRP3-associated inflammation. These findings suggest that OL glycolytic deficiency plays a causal role in AD development. The Drp1-HK1-NLRP3 signaling axis may be a key mechanism and therapeutic target for white matter degeneration in AD.

BAM15-mediated mitochondrial uncoupling protects against obesity and improves glycemic control

Obesity is a leading cause of preventable death worldwide. Despite this, current strategies for the treatment of obesity remain ineffective at achieving long-term weight control. This is due, in part, to difficulties in identifying tolerable and efficacious small molecules or biologics capable of regulating systemic nutrient homeostasis. Here, we demonstrate that BAM15, a mitochondrially targeted small molecule protonophore, stimulates energy expenditure and glucose and lipid metabolism to protect against diet-induced obesity. Exposure to BAM15 in vitro enhanced mitochondrial respiratory kinetics, improved insulin action, and stimulated nutrient uptake by sustained activation of AMPK. C57BL/6J mice treated with BAM15 were resistant to weight gain. Furthermore, BAM15-treated mice exhibited improved body composition and glycemic control independent of weight loss, effects attributable to drug targeting of lipid-rich tissues. We provide the first phenotypic characterization and demonstration of pre-clinical efficacy for BAM15 as a pharmacological approach for the treatment of obesity and related diseases.

Massive release of CD9+ microvesicles in HIV infection, regardless of virologic control

Background

The role of extracellular vesicles (EVs) in human immunodeficiency virus (HIV) pathogenesis is unknown. We examine the cellular origin of plasma microvesicles (MVs), a type of ectocytosis-derived EV, the presence of mitochondria in MVs, and their relationship to circulating cell-free mitochondrial deoxyribonucleic acid (ccf-mtDNA) in HIV-infected patients and controls.

Methods

Five participant groups were defined: 30 antiretroviral therapy (ART)-naive; 30 ART-treated with nondetectable viremia; 30 elite controllers; 30 viremic controllers; and 30 HIV-uninfected controls. Microvesicles were quantified and characterized from plasma samples by flow cytometry. MitoTrackerDeepRed identified MVs containing mitochondria and ccf-mtDNA was quantified by real-time polymerase chain reaction.

Results

Microvesicle numbers were expanded at least 10-fold in all HIV-infected groups compared with controls. More than 79% were platelet-derived MVs. Proportions of MVs containing mitochondria (22.3% vs 41.6%) and MV mitochondrial density (706 vs 1346) were significantly lower among HIV-infected subjects than controls, lowest levels for those on ART. Microvesicle numbers correlated with ccf-mtDNA levels that were higher among HIV-infected patients.

Conclusions

A massive release of platelet-derived MVs occurs during HIV infection. Some MVs contain mitochondria, but their proportion and mitochondrial densities were lower in HIV infection than in controls. Platelet-derived MVs may be biomarkers of platelet activation, possibly reflecting pathogenesis even in absence of HIV replication.

FAM222A encodes a protein which accumulates in plaques in Alzheimer's disease

Alzheimer's disease (AD) is characterized by amyloid plaques and progressive cerebral atrophy. Here, we report FAM222A as a putative brain atrophy susceptibility gene. Our cross-phenotype association analysis of imaging genetics indicates a potential link between FAM222A and AD-related regional brain atrophy. The protein encoded by FAM222A is predominantly expressed in the CNS and is increased in brains of patients with AD and in an AD mouse model. It accumulates within amyloid deposits, physically interacts with amyloid-β (Aβ) via its N-terminal Aβ binding domain, and facilitates Aβ aggregation. Intracerebroventricular infusion or forced expression of this protein exacerbates neuroinflammation and cognitive dysfunction in an AD mouse model whereas ablation of this protein suppresses the formation of amyloid deposits, neuroinflammation and cognitive deficits in the AD mouse model. Our data support the pathological relevance of protein encoded by FAM222A in AD.

Mfn2 Ablation in the Adult Mouse Hippocampus and Cortex Causes Neuronal Death

It is believed that mitochondrial fragmentation cause mitochondrial dysfunction and neuronal deficits in Alzheimer's disease. We recently reported that constitutive knockout of the mitochondria fusion protein mitofusin2 (Mfn2) in the mouse brain causes mitochondrial fragmentation and neurodegeneration in the hippocampus and cortex. Here, we utilize an inducible mouse model to knock out Mfn2 (Mfn2 iKO) in adult mouse hippocampal and cortical neurons to avoid complications due to developmental changes. Electron microscopy shows the mitochondria become swollen with disorganized and degenerated cristae, accompanied by increased oxidative damage 8 weeks after induction, yet the neurons appear normal at the light level. At later timepoints, increased astrocyte and microglia activation appear and nuclei become shrunken and pyknotic. Apoptosis (Terminal deoxynucleotidyl transferase dUTP nick end labeling, TUNEL) begins to occur at 9 weeks, and by 12 weeks, most hippocampal neurons are degenerated, confirmed by loss of NeuN. Prior to the loss of NeuN, aberrant cell-cycle events as marked by proliferating cell nuclear antigen (PCNA) and pHistone3 were evident in some Mfn2 iKO neurons but do not colocalize with TUNEL signals. Thus, this study demonstrated that Mfn2 ablation and mitochondrial fragmentation in adult neurons cause neurodegeneration through oxidative stress and neuroinflammation in vivo via both apoptosis and aberrant cell-cycle-event-dependent cell death pathways.

Liquid plug formation in an airway closure model

The closure of a human lung airway is modeled as an instability of a two-phase flow in a pipe coated internally with a Newtonian liquid. For a thick enough coating, the Plateau-Rayleigh instability creates a liquid plug which blocks the airway, halting distal gas exchange. Owing to a bi-frontal plug growth, this airway closure flow induces high stress levels on the wall, which is the location of airway epithelial cells. A parametric numerical study is carried out simulating relevant conditions for human lungs, either in ordinary or pathological situations. Our simulations can represent the physical process from pre- to post-coalescence phases. Previous studies have been limited to pre-coalescence only. The topological change during coalescence induces a high level of stress and stress gradients on the epithelial cells, which are large enough to damage them, causing sub-lethal or lethal responses. We find that post-coalescence wall stresses can be in the range of 300% to 600% greater than pre-coalescence values, so introduce a new important source of mechanical perturbation to the cells.

Effects of surfactant on propagation and rupture of a liquid plug in a tube

Surfactant-laden liquid plug propagation and rupture occurring in lower lung airways are studied computationally using a front-tracking method. The plug is driven by an applied constant pressure in a rigid axisymmetric tube whose inner surface is coated by a thin liquid film. The evolution equations of the interfacial and bulk surfactant concentrations coupled with the incompressible Navier-Stokes equations are solved in the front-tracking framework. The numerical method is first validated for a surfactant-free case and the results are found to be in good agreement with the earlier simulations of Fujioka et al. (2008) and Hassan et al. (2011). Then extensive simulations are performed to investigate the effects of surfactant on the mechanical stresses that could be injurious to epithelial cells such as pressure and shear stress. It is found that the liquid plug ruptures violently to induce large pressure and shear stress on airway walls and even a tiny amount of surfactant significantly reduces the pressure and shear stress and thus improves cell survivability. However, addition of surfactant also delays the plug rupture and thus airway reopening.

Isolation of mitochondrial subpopulations from skeletal muscle: Optimizing recovery and preserving integrity

AIM

The subsarcolemmal (SSM) and interfibrillar (IFM) mitochondria in skeletal muscle appear to have distinct biochemical properties affecting metabolism in health and disease. The isolation of mitochondrial subpopulations has been a long-time challenge while the presence of a continuous mitochondrial reticulum challenges the view of distinctive SSM and IFM bioenergetics. Here, a comprehensive approach is developed to identify the best conditions to separate mitochondrial fractions.

METHODS

The main modifications to the protocol to isolate SSM and IFM from rat skeletal muscle were: (a) decreased dispase content and homogenization speed; (b) trypsin treatment of SSM fractions; (c) recentrifugation of mitochondrial fractions at low speed to remove subcellular components. To identify the conditions preserving mitochondrial function, integrity, and maximizing their recovery, microscopy (light and electron) were used to monitor effectiveness and efficiency in separating mitochondrial subpopulations while respiratory and enzyme activities were employed to evaluate function, recovery, and integrity.

RESULTS

With the modifications described, the total mitochondrial yield increased with a recovery of 80% of mitochondria contained in the original skeletal muscle sample. The difference between SSM and IFM oxidative capacity (10%) with complex-I substrate was significant only with a saturated ADP concentration. The inner and outer membrane damage for both subpopulations was <1% and 8%, respectively, while the respiratory control ratio was 16.

CONCLUSION

Using a multidisciplinary approach, conditions were identified to maximize SSM and IFM recovery while preserving mitochondrial integrity, biochemistry, and morphology. High quality and recovery of mitochondrial subpopulations allow to study the relationship between these organelles and disease.

Dominance of Tensor Correlations in High-Momentum Nucleon Pairs Studied by (p,pd) Reaction

The isospin character of p-n pairs at large relative momentum has been observed for the first time in the ^{16}O ground state. A strong population of the J,T=1,0 state and a very weak population of the J,T=0,1 state were observed in the neutron pickup domain of ^{16}O(p,pd) at 392 MeV. This strong isospin dependence at large momentum transfer is not reproduced by the distorted-wave impulse approximation calculations with known spectroscopic amplitudes. The results indicate the presence of high-momentum protons and neutrons induced by the tensor interactions in the ground state of ^{16}O.

Mitofusin 2 Regulates Axonal Transport of Calpastatin to Prevent Neuromuscular Synaptic Elimination in Skeletal Muscles

Skeletal muscles undergo atrophy in response to diseases and aging. Here we report that mitofusin 2 (Mfn2) acts as a dominant suppressor of neuromuscular synaptic loss to preserve skeletal muscles. Mfn2 is reduced in spinal cords of transgenic SOD1^G93A and aged mice. Through preserving neuromuscular synapses, increasing neuronal Mfn2 prevents skeletal muscle wasting in both SOD1^G93A and aged mice, whereas deletion of neuronal Mfn2 produces neuromuscular synaptic dysfunction and skeletal muscle atrophy. Neuromuscular synaptic loss after sciatic nerve transection can also be alleviated by Mfn2. Mfn2 coexists with calpastatin largely in mitochondria-associated membranes (MAMs) to regulate its axonal transport. Genetic inactivation of calpastatin abolishes Mfn2-mediated protection of neuromuscular synapses. Our results suggest that, as a potential key component of a novel and heretofore unrecognized mechanism of cytoplasmic protein transport, Mfn2 may play a general role in preserving neuromuscular synapses and serve as a common therapeutic target for skeletal muscle atrophy.

Mitophagy is required for brown adipose tissue mitochondrial homeostasis during cold challenge

Brown adipose tissue (BAT) is a specialized thermogenic organ in mammals. The ability of BAT mitochondria to generate heat in response to cold-challenge to maintain core body temperature is essential for organismal survival. While cold activated BAT mitochondrial biogenesis is recognized as critical for thermogenic adaptation, the contribution of mitochondrial quality control to this process remains unclear. Here, we show mitophagy is required for brown adipocyte mitochondrial homeostasis during thermogenic adaptation. Mitophagy is significantly increased in BAT from cold-challenged mice (4 °C) and in β-agonist treated brown adipocytes. Blockade of mitophagy compromises brown adipocytes mitochondrial oxidative phosphorylation (OX-PHOS) capacity, as well as BAT mitochondrial integrity. Mechanistically, cold-challenge induction of BAT mitophagy is UCP1-dependent. Furthermore, our results indicate that mitophagy coordinates with mitochondrial biogenesis, maintaining activated BAT mitochondrial homeostasis. Collectively, our in vivo and in vitro findings identify mitophagy as critical for brown adipocyte mitochondrial homeostasis during cold adaptation.

Spectroscopy of Pionic Atoms in ^{122}Sn(d,^{3}He) Reaction and Angular Dependence of the Formation Cross Sections

We observed the atomic 1s and 2p states of π^{-} bound to ^{121}Sn nuclei as distinct peak structures in the missing mass spectra of the ^{122}Sn(d,^{3}He) nuclear reaction. A very intense deuteron beam and a spectrometer with a large angular acceptance let us achieve a potential of discovery, which includes the capability of determining the angle-dependent cross sections with high statistics. The 2p state in a Sn nucleus was observed for the first time. The binding energies and widths of the pionic states are determined and found to be consistent with previous experimental results of other Sn isotopes. The spectrum is measured at finite reaction angles for the first time. The formation cross sections at the reaction angles between 0° and 2° are determined. The observed reaction-angle dependence of each state is reproduced by theoretical calculations. However, the quantitative comparison with our high-precision data reveals a significant discrepancy between the measured and calculated formation cross sections of the pionic 1s state.

Inhibition of mitochondrial fragmentation protects against Alzheimer's disease in rodent model

Mitochondrial dysfunction is an early prominent feature in susceptible neurons in the brain of patients with Alzheimer's disease, which likely plays a critical role in the pathogenesis of disease. Increasing evidence suggests abnormal mitochondrial dynamics as important underlying mechanisms. In this study, we characterized marked mitochondrial fragmentation and abnormal mitochondrial distribution in the pyramidal neurons along with mitochondrial dysfunction in the brain of Alzheimer's disease mouse model CRND8 as early as 3 months of age before the accumulation of amyloid pathology. To establish the pathogenic significance of these abnormalities, we inhibited mitochondrial fragmentation by the treatment of mitochondrial division inhibitor 1 (mdivi-1), a mitochondrial fission inhibitor. Mdivi-1 treatment could rescue both mitochondrial fragmentation and distribution deficits and improve mitochondrial function in the CRND8 neurons both in vitro and in vivo. More importantly, the amelioration of mitochondrial dynamic deficits by mdivi-1 treatment markedly decreased extracellular amyloid deposition and Aβ1-42/Aβ1-40 ratio, prevented the development of cognitive deficits in Y-maze test and improved synaptic parameters. Our findings support the notion that abnormal mitochondrial dynamics plays an early and causal role in mitochondrial dysfunction and Alzheimer's disease-related pathological and cognitive impairments in vivo and indicate the potential value of restoration of mitochondrial dynamics as an innovative therapeutic strategy for Alzheimer's disease.

Conceptual Perspectives: Bacterial Antimicrobial Peptide Induction as a Novel Strategy for Symbiosis with the Human Host

Human beta defensins (hBDs) are small cationic peptides, expressed in mucosal epithelia and important agents of innate immunity, act as antimicrobial and chemotactic agents at mucosal barriers. In this perspective, we present evidence supporting a novel strategy by which the oral bacterium Fusobacterium nucleatum induces hBDs and other antimicrobial peptides (AMPs) in normal human oral epithelial cells (HOECs) and thereby protects them from other microbial pathogens. The findings stress (1) the physiological importance of hBDs, (2) that this strategy may be a mechanism that contributes to homeostasis and health in body sites constantly challenged with bacteria and (3) that novel properties identified in commensal bacteria could, one day, be harnessed as new probiotic strategies to combat colonization of opportunistic pathogens. With that in mind, we highlight and review the discovery and characterization of a novel lipo-protein, FAD-I (FusobacteriumAssociated Defensin Inducer) associated with the outer membrane of F. nucleatum that may act as a homeostatic agent by activating endogenous AMPs to re-equilibrate a dysregulated microenvironment. FAD-I has the potential to reduce dysbiosis-driven diseases at a time when resistance to antibiotics is increasing. We therefore postulate that FAD-I may offer a new paradigm in immunoregulatory therapeutics to bolster host innate defense of vulnerable mucosae, while maintaining physiologically responsive states of inflammation.

Mfn2 ablation causes an oxidative stress response and eventual neuronal death in the hippocampus and cortex

Background

Mitochondria are the organelles responsible for energy metabolism and have a direct impact on neuronal function and survival. Mitochondrial abnormalities have been well characterized in Alzheimer Disease (AD). It is believed that mitochondrial fragmentation, due to impaired fission and fusion balance, likely causes mitochondrial dysfunction that underlies many aspects of neurodegenerative changes in AD. Mitochondrial fission and fusion proteins play a major role in maintaining the health and function of these important organelles. Mitofusion 2 (Mfn2) is one such protein that regulates mitochondrial fusion in which mutations lead to the neurological disease.

Methods

To examine whether and how impaired mitochondrial fission/fusion balance causes neurodegeneration in AD, we developed a transgenic mouse model using the CAMKII promoter to knockout neuronal Mfn2 in the hippocampus and cortex, areas significantly affected in AD.

Results

Electron micrographs of neurons from these mice show swollen mitochondria with cristae damage and mitochondria membrane abnormalities. Over time the Mfn2 cKO model demonstrates a progression of neurodegeneration via mitochondrial morphological changes, oxidative stress response, inflammatory changes, and loss of MAP2 in dendrites, leading to severe and selective neuronal death. In this model, hippocampal CA1 neurons were affected earlier and resulted in nearly total loss, while in the cortex, progressive neuronal death was associated with decreased cortical size.

Conclusions

Overall, our findings indicate that impaired mitochondrial fission and fusion balance can cause many of the neurodegenerative changes and eventual neuron loss that characterize AD in the hippocampus and cortex which makes it a potential target for treatment strategies for AD.

Electronic supplementary material

The online version of this article (10.1186/s13024-018-0238-8) contains supplementary material, which is available to authorized users.

A conserved KLF-autophagy pathway modulates nematode lifespan and mammalian age-associated vascular dysfunction

Loss of protein and organelle quality control secondary to reduced autophagy is a hallmark of aging. However, the physiologic and molecular regulation of autophagy in long-lived organisms remains incompletely understood. Here we show that the Kruppel-like family of transcription factors are important regulators of autophagy and healthspan in C. elegans, and also modulate mammalian vascular age-associated phenotypes. Kruppel-like family of transcription factor deficiency attenuates autophagy and lifespan extension across mechanistically distinct longevity nematode models. Conversely, Kruppel-like family of transcription factor overexpression extends nematode lifespan in an autophagy-dependent manner. Furthermore, we show the mammalian vascular factor Kruppel-like family of transcription factor 4 has a conserved role in augmenting autophagy and improving vessel function in aged mice. Kruppel-like family of transcription factor 4 expression also decreases with age in human vascular endothelium. Thus, Kruppel-like family of transcription factors constitute a transcriptional regulatory point for the modulation of autophagy and longevity in C. elegans with conserved effects in the murine vasculature and potential implications for mammalian vascular aging.KLF family transcription factors (KLFs) regulate many cellular processes, including proliferation, survival and stress responses. Here, the authors position KLFs as important regulators of autophagy and lifespan in C. elegans, a role that may extend to the modulation of age-associated vascular phenotypes in mammals.

Soluble polymorphic bank vole prion proteins induced by co-expression of quiescin sulfhydryl oxidase in E. coli and their aggregation behaviors

Background

The infectious prion protein (PrP^Sc or prion) is derived from its cellular form (PrP^C) through a conformational transition in animal and human prion diseases. Studies have shown that the interspecies conversion of PrP^C to PrP^Sc is largely swayed by species barriers, which is mainly deciphered by the sequence and conformation of the proteins among species. However, the bank vole PrP^C (BVPrP) is highly susceptible to PrP^Sc from different species. Transgenic mice expressing BVPrP with the polymorphic isoleucine (109I) but methionine (109M) at residue 109 spontaneously develop prion disease.

Results

To explore the mechanism underlying the unique susceptibility and convertibility, we generated soluble BVPrP by co-expression of BVPrP with Quiescin sulfhydryl oxidase (QSOX) in Escherichia coli. Interestingly, rBVPrP-109M and rBVPrP-109I exhibited distinct seeded aggregation pathways and aggregate morphologies upon seeding of mouse recombinant PrP fibrils, as monitored by thioflavin T fluorescence and electron microscopy. Moreover, they displayed different aggregation behaviors induced by seeding of hamster and mouse prion strains under real-time quaking-induced conversion.

Conclusions

Our results suggest that QSOX facilitates the formation of soluble prion protein and provide further evidence that the polymorphism at residue 109 of QSOX-induced BVPrP may be a determinant in mediating its distinct convertibility and susceptibility.

Short-term administration of Nicotinamide Mononucleotide preserves cardiac mitochondrial homeostasis and prevents heart failure

Heart failure is associated with mitochondrial dysfunction so that restoring or improving mitochondrial health is of therapeutic importance. Recently, reduction in NAD⁺ levels and NAD⁺-mediated deacetylase activity has been recognized as negative regulators of mitochondrial function. Using a cardiac specific KLF4 deficient mouse line that is sensitive to stress, we found mitochondrial protein hyperacetylation coupled with reduced Sirt3 and NAD⁺ levels in the heart before stress, suggesting that the KLF4-deficient heart is predisposed to NAD⁺-associated defects. Further, we demonstrated that short-term administration of Nicotinamide Mononucleotide (NMN) successfully protected the mutant mice from pressure overload-induced heart failure. Mechanically, we showed that NMN preserved mitochondrial ultrastructure, reduced ROS and prevented cell death in the heart. In cultured cardiomyocytes, NMN treatment significantly increased long-chain fatty acid oxidation despite no direct effect on pyruvate oxidation. Collectively, these results provide cogent evidence that hyperacetylation of mitochondrial proteins is critical in the pathogenesis of cardiac disease and that administration of NMN may serve as a promising therapy.

Cetylpyridinium Chloride (CPC) Exhibits Potent, Rapid Activity Against Influenza Viruses in vitro and in vivo

Background:

There is a continued need for strategies to prevent influenza. While cetylpyridinium chloride (CPC), a broad-spectrum antimicrobial agent, has an extensive antimicrobial spectrum, its ability to affect respiratory viruses has not been studied in detail.

Objectives:

Here, we evaluate the ability of CPC to disrupt influenza viruses in vitro and in vivo.

Methods:

The virucidal activity of CPC was evaluated against susceptible and oseltamivir- resistant strains of influenza viruses. The effective virucidal concentration (EC) of CPC was determined using a hemagglutination assay and tissue culture infective dose assay. The effect of CPC on viral envelope morphology and ultrastructure was evaluated using transmission electron microscopy (TEM). The ability of influenza virus to develop resistance was evaluated after multiple passaging in sub-inhibitory concentrations of CPC. Finally, the efficacy of CPC in formulation to prevent and treat influenza infection was evaluated using the PR8 murine influenza model.

Results:

The virucidal effect of CPC occurred within 10 minutes, with mean EC₅₀ and EC_2log ranging between 5 to 20 μg/mL, for most strains of influenza tested regardless of type and resistance to oseltamivir. Examinations using TEM showed that CPC disrupted the integrity of the viral envelope and its morphology. Influenza viruses demonstrated no resistance to CPC despite prolonged exposure. Treated mice exhibited significantly increased survival and maintained body weight compared to untreated mice.

Conclusions:

The antimicrobial agent CPC possesses virucidal activity against susceptible and resistant strains of influenza virus by targeting and disrupting the viral envelope. Substantial virucidal activity is seen even at very low concentrations of CPC without development of resistance. Moreover, CPC in formulation reduces influenza-associated mortality and morbidity in vivo.

Repeated Intraportal Hepatocyte Transplantation in Analbuminemic Rats

The optimal site for implantation of isolated hepatocytes has not been established. We have developed a novel technique which allows repeated infusion of hepatocytes into the portal system via an indwelling catheter. Seven Nagase Analbuminemic rats (NAR) underwent single intra-portal infusion of 2 × 107 isolated normal albumin-producing rat hepatocytes. Another seven NAR rats underwent placement of indwelling catheters into the portal venous system via the gastroduodenal vein. Each of them received six batches of 5 × 106 normal albumin producing hepatocytes. Seven control NAR rats were infused repeatedly (intraportally) with saline only. Plasma albumin (ELISA) showed significant increase in experimental animals and was more pronounced (p < 0.05) in rats transplanted repeatedly than in those given a single dose of cells. Immunohistochemical staining of the liver sections confirmed the presence of transplanted albumin producing hepatocytes. Rats transplanted with a single large batch of isolated hepatocytes showed liver tissue damage, whereas those subjected to repeated cell infusions had normal liver histology. We have developed a novel intraportal transplantation method which allows successful engraftment of a large number of isolated hepatocytes.

KLF2 and KLF4 control endothelial identity and vascular integrity

Maintenance of vascular integrity in the adult animal is needed for survival, and it is critically dependent on the endothelial lining, which controls barrier function, blood fluidity, and flow dynamics. However, nodal regulators that coordinate endothelial identity and function in the adult animal remain poorly characterized. Here, we show that endothelial KLF2 and KLF4 control a large segment of the endothelial transcriptome, thereby affecting virtually all key endothelial functions. Inducible endothelial-specific deletion of Klf2 and/or Klf4 reveals that a single allele of either gene is sufficient for survival, but absence of both (EC-DKO) results in acute death from myocardial infarction, heart failure, and stroke. EC-DKO animals exhibit profound compromise in vascular integrity and profound dysregulation of the coagulation system. Collectively, these studies establish an absolute requirement for KLF2/4 for maintenance of endothelial and vascular integrity in the adult animal.

Association Between Germline Mutation in VSIG10L and Familial Barrett Neoplasia

Importance

Esophageal adenocarcinoma and its precursor lesion Barrett esophagus have seen a dramatic increase in incidence over the past 4 decades yet marked genetic heterogeneity of this disease has precluded advances in understanding its pathogenesis and improving treatment.

Objective

To identify novel disease susceptibility variants in a familial syndrome of esophageal adenocarcinoma and Barrett esophagus, termed familial Barrett esophagus, by using high-throughput sequencing in affected individuals from a large, multigenerational family.

Design, Setting, and Participants

We performed whole exome sequencing (WES) from peripheral lymphocyte DNA on 4 distant relatives from our multiplex, multigenerational familial Barrett esophagus family to identify candidate disease susceptibility variants. Gene variants were filtered, verified, and segregation analysis performed to identify a single candidate variant. Gene expression analysis was done with both quantitative real-time polymerase chain reaction and in situ RNA hybridization. A 3-dimensional organotypic cell culture model of esophageal maturation was utilized to determine the phenotypic effects of our gene variant. We used electron microscopy on esophageal mucosa from an affected family member carrying the gene variant to assess ultrastructural changes.

Main Outcomes and Measures

Identification of a novel, germline disease susceptibility variant in a previously uncharacterized gene.

Results

A multiplex, multigenerational family with 14 members affected (3 members with esophageal adenocarcinoma and 11 with Barrett esophagus) was identified, and whole-exome sequencing identified a germline mutation (S631G) at a highly conserved serine residue in the uncharacterized gene VSIG10L that segregated in affected members. Transfection of S631G variant into a 3-dimensional organotypic culture model of normal esophageal squamous cells dramatically inhibited epithelial maturation compared with the wild-type. VSIG10L exhibited high expression in normal squamous esophagus with marked loss of expression in Barrett-associated lesions. Electron microscopy of squamous esophageal mucosa harboring the S631G variant revealed dilated intercellular spaces and reduced desmosomes.

Conclusions and Relevance

This study presents VSIG10L as a candidate familial Barrett esophagus susceptibility gene, with a putative role in maintaining normal esophageal homeostasis. Further research assessing VSIG10L function may reveal pathways important for esophageal maturation and the pathogenesis of Barrett esophagus and esophageal adenocarcinoma.