Osteoarthritis (OA) is the leading form of arthritis in the elderly, causing pain, disability, and immobility. OA has been associated with accumulation of senescent cells in or near joints. However, evidence for a causal link between OA and cellular senescence is lacking. Here, we present a novel senescent cell transplantation model involving injection of small numbers of senescent or nonsenescent cells from the ear cartilage of luciferase-expressing mice into the knee joint area of wild-type mice. By using bioluminescence and 18FDG PET imaging, we could track the injected cells in vivo for more than 10 days. Transplanting senescent cells into the knee region caused leg pain, impaired mobility, and radiographic and histological changes suggestive of OA. Transplanting nonsenescent cells had less of these effects. Thus, senescent cells can induce an OA-like state and targeting senescent cells could be a promising strategy for treating OA.

Impaired brain clearance of amyloid-beta peptides (Aβ) 40 and 42 across the blood-brain barrier (BBB) is believed to be one of the pathways responsible for Alzheimer's disease (AD) pathogenesis. Hyperinsulinemia prevalent in type II diabetes was shown to damage cerebral vasculature and increase Aβ accumulation in AD brain. However, there is no clarity on how aberrations in peripheral insulin levels affect Aβ accumulation in the brain. This study describes, for the first time, an intricate relation between plasma insulin and Aβ transport at the BBB. Upon peripheral insulin administration in wild-type mice: the plasma clearance of Aβ40 increased, but Aβ42 clearance reduced; the plasma-to-brain influx of Aβ40 increased, and that of Aβ42 reduced; and the clearance of intracerebrally injected Aβ40 decreased, whereas Aβ42 clearance increased. In hCMEC/D3 monolayers (in vitro BBB model) exposed to insulin, the luminal uptake and luminal-to-abluminal permeability of Aβ40 increased and that of Aβ42 reduced; the abluminal-to-luminal permeability of Aβ40 decreased, whereas Aβ42 permeability increased. Moreover, Aβ cellular trafficking machinery was altered. In summary, Aβ40 and Aβ42 demonstrated distinct distribution kinetics in plasma and brain compartments, and insulin differentially modulated their distribution. Cerebrovascular disease and metabolic disorders may disrupt this intricate homeostasis and aggravate AD pathology.

BackgroundTherapeutic intervention of numerous brain-associated disorders currently remains unrealized due to serious limitations imposed by the blood-brain-barrier (BBB). The BBB generally allows transport of small molecules, typically <600 daltons with high octanol/water partition coefficients, but denies passage to most larger molecules. However, some receptors present on the BBB allow passage of cognate proteins to the brain. Utilizing such receptor-ligand systems, several investigators have developed methods for delivering proteins to the brain, a critical requirement of which involves covalent linking of the target protein to a carrier entity. Such covalent modifications involve extensive preparative and post-preparative chemistry that poses daunting limitations in the context of delivery to any organ. Here, we report creation of a 36-amino acid peptide transporter, which can transport a protein to the brain after routine intravenous injection of the transporter-protein mixture. No covalent linkage of the protein with the transporter is necessary.ApproachA peptide transporter comprising sixteen lysine residues and 20 amino acids corresponding to the LDLR-binding domain of apolipoprotein E (ApoE) was synthesized. Transport of beta-galactosidase, IgG, IgM, and antibodies against amyloid plques to the brain upon iv injection of the protein-transporter mixture was evaluated through staining for enzyme activity or micro single photon emission tomography (micro-SPECT) or immunostaining. Effect of the transporter on the integrity of the BBB was also investigated.Principal FindingsThe transporter enabled delivery to the mouse brain of functional beta-galactosidase, human IgG and IgM, and two antibodies that labeled brain-associated amyloid beta plaques in a mouse model of Alzheimer's disease.SignificanceThe results suggest the transporter is able to transport most or all proteins to the brain without the need for chemically linking the transporter to a protein. Thus, the approach offers an avenue for rapid clinical evaluation of numerous candidate drugs against neurological diseases including cancer. (299 words).

Breast cancer radiotherapy increases the risk of heart failure with preserved ejection fraction (HFpEF). Cardiomyocytes are highly radioresistant, but radiation specifically affects coronary microvascular endothelial cells, with subsequent microvascular inflammation and rarefaction. The effects of radiation on left ventricular (LV) diastolic function are poorly characterized. We hypothesized that cardiac radiation exposure may result in diastolic dysfunction without reduced EF. Global cardiac expression of the sodium-iodide symporter (NIS) was induced by cardiotropic gene (adeno-associated virus serotype 9) delivery to 5-wk-old rats. SPECT/CT (I) measurement of cardiac iodine uptake allowed calculation of the I doses needed to deliver 10- or 20-Gy cardiac radiation at 10 wk of age. Radiated (Rad; 10 or 20 Gy) and control rats were studied at 30 wk of age. Body weight, blood pressure, and heart rate were similar in control and Rad rats. Compared with control rats, Rad rats had impaired exercise capacity, increased LV diastolic stiffness, impaired LV relaxation, and elevated filling pressures but similar LV volume, EF, end-systolic elastance, preload recruitable stroke work, and peak +dP/d Pathology revealed reduced microvascular density, mild concentric cardiomyocyte hypertrophy, and increased LV fibrosis in Rad rats compared with control rats. In the Rad myocardium, oxidative stress was increased and in vivo PKG activity was decreased. Experimental cardiac radiation exposure resulted in diastolic dysfunction without reduced EF. These data provide insight into the association between cardiac radiation exposure and HFpEF risk and lend further support for the importance of inflammation-related coronary microvascular compromise in HFpEF. Cardiac radiation exposure during radiotherapy increases the risk of heart failure with preserved ejection fraction. In a novel rodent model, cardiac radiation exposure resulted in coronary microvascular rarefaction, oxidative stress, impaired PKG signaling, myocardial fibrosis, mild cardiomyocyte hypertrophy, left ventricular diastolic dysfunction, and elevated left ventricular filling pressures despite preserved ejection fraction.

Several clinical trials have shown that oncolytic herpes simplex virus type 1 (oHSV-1) can be safely administered to patients. However, virus replication in tumor tissue has generally not been monitored in these oHSV clinical trials, and the data suggest that its oncolytic potency needs to be improved. To facilitate noninvasive monitoring of the in vivo spread of an oHSV and to increase its antitumor efficacy, the gene coding for human sodium iodide symporter (NIS) was incorporated into a recombinant oHSV genome and the corresponding virus (oHSV-NIS) rescued in our laboratory. Our data demonstrate that a human prostate cancer cell line, LNCap, efficiently concentrates radioactive iodine after the cells have been infected in vitro or in vivo. In vivo replication of oHSV-NIS in tumors was noninvasively monitored by computed tomography/single-photon emission computed tomography imaging of the biodistribution of pertechnetate and was confirmed. LNCap xenografts in nude mice were eradicated by intratumoral administration of oHSV-NIS. Systemic administration of oHSV-NIS prolonged the survival of tumor-bearing mice, and the therapeutic effect was further enhanced by administration of 131I after the intratumoral spread of the virus had peaked. oHSV-NIS has the potential to substantially enhance the outcomes of standard therapy for patients with prostate cancer.

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Background Decreased brain insulin levels exacerbate cognitive decline in AD. Insulin in the brain is derived from systemic circulation via the blood‐brain barrier (BBB). We hypothesize that type II diabetes (T2D) sequelae and Aβ peptide exposure disrupt insulin signaling at the BBB and inhibit insulin delivery to brain. Further, we propose insulin signaling defects at the BBB contribute to Aβ accumulation in AD brain. Methods The following studies were performed in wild‐type (WT) mice on regular chow (RC) diet, WT mice on high fat (HF) diet (manifest insulin resistance), APP/PS1 transgenic mice on RC diet (overexpress Aβ), and APP/PS1 mice on HF diet (overexpress Aβ + insulin resistance). After femoral injection of 125I‐insulin or 125I‐Aβ42, the brain accumulation was monitored between 0‐40 min by dynamic SPECT/CT imaging. The brain influx clearance was estimated by the slope obtained from Gjedde‐Patlak graphical analysis. Cerebral microvessels were harvested, and reverse phase protein array (RPPA) was performed to examine insulin signaling changes. Differentially expressed targets were subsequently confirmed by western blot. The brain influx of 125I‐insulin and 125I‐Aβ42 were further assessed in WT‐RC mice after internal carotid infusion with AG1024, a kinase inhibitor of the insulin receptor (IR) and insulin‐like growth factor receptor (IGF‐1R). Results Compared to WT‐RC, 125I‐insulin influx was decreased in WT‐HF and APP/PS1‐RC, and was further decreased in APP/PS1‐HF (4.1, 3.4, 3.5 and 2.6*10‐4 mL/min, respectively). Compared to WT‐RC, 125I‐Aβ42 influx was increased in WT‐HF and APP/PS1‐RC (8.6, 28 and 23*10‐4 mL/min, respectively). RPPA analysis revealed global disruptions in BBB insulin signaling pathways. Western blots confirmed reduced expression of IR‐β, p‐AKT and p‐GSK3β in WT‐HF and APP/PS1‐RC compared to WT‐RC. Moreover, the largest decreases were observed in APP/PS1‐HF. Infusion with AG1024 was shown to decrease 125I‐insulin influx, but increase 125I‐Aβ42 influx. Conclusions Both T2D and AD mice exhibited decreased brain influx of insulin and increased influx of Aβ42. This was associated with altered expression/activity of insulin signaling kinases at the BBB. Further, IR and/or IGF‐1R kinase activity were shown to differentially regulate BBB trafficking of insulin and Aβ42. Thus, BBB insulin signaling is important for delivering insulin to brain and restricting pathological uptake of Aβ.