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Query: UNIPROT:P02794 (
ferritin
)
17,525
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Anionic microdomains within the aortic smooth muscle cell (SMC) surface glycocalyx represent a potential barrier to the endocytosis of anionic plasma proteins. Cultured SMCs exposed briefly to cationized
ferritin
(CF) exhibit ultrastructural aggregations of surface anionic sites resulting in intervening areas essentially devoid of anionic charge. Preincubation of cultured aortic medial SMCs with 0.2 mg/ml CF for 1 minute at 37 C resulted in a 4-fold increase in binding and a 13-fold increase in internalization of 125I-human serum albumin (125I-HSA) relative to cells pretreated with native
ferritin
. When both the CF preincubation and the endocytosis were performed at 4 C, the influence of CF was abolished. Studies at 4 C indicated that CF pretreatment of SMC at 37 C induced high affinity (Kd = 1.5 nM) saturable 125I-
HSA
binding, in addition to low-affinity nonsaturable binding. These results were further confirmed by binding competition studies using increasing concentrations of unlabeled
HSA
. In contrast, low-density lipoprotein, a large anionic molecule, failed to compete with 125I-
HSA
for binding sites on CF-pretreated SMCs at either 4 or 37 C. Pulse-chase studies at 37 C indicated that 20-30% of internalized 125I-
HSA
was degraded, and 40-50% exocytosed within 24 hours in CF-treated cells. CF pretreatment of the SMCs did not significantly enhance the uptake of 14C-sucrose as a measure of fluid-phase endocytosis at 30 and 60 minutes. The results of these studies emphasize the potentially important regulatory roles of cell-surface anionic charge distribution and cationic molecules in cellular endocytosis.
...
PMID:Stimulation of albumin endocytosis by cationized ferritin in cultured aortic smooth muscle cells. 407 18
We have suggested that renal tubular synthesis of C3 and its activation in the cortical interstitium is a mechanism for the progression of glomerulonephritis to interstitial injury. To test this hypothesis, immune complex glomerulonephritis was induced in C57BL/6 mice by intraperitoneal injections of horse spleen
apoferritin
and lipopolysaccharide (
HSA
/LPS). When compared to wild-type (WT) animals, C3 knockout (C3KO) mice had glomerular changes that were identical. Morphometric analysis of the cortical interstitium, however, showed marked differences. WT mice had more interstitial inflammation, edema, and tubular atrophy, when compared to C3KO mice. At the end of the experiment, WT animals also had significantly more proteinuria than did C3KOs. These experiments provide further evidence of a role of locally synthesized complement in the progression of glomerular disease.
...
PMID:C3 is central to the interstitial component of experimental immune complex glomerulonephritis. 1587 25
Skeletal demineralization is a frequent accompaniment of chronic renal disease and is likely multifactorial. We studied the role of inflammation in stimulating bone resorption in a rat model of glomerulonephritis (GN). Three-week-old Sprague-Dawley rats received either saline (n = 8) or horse spleen
apoferritin
and lipopolysaccharide (
HSA
/LPS, n = 8) by intraperitoneal injection, for 6 weeks; afterward, they were observed for either an additional 3 weeks (9 weeks total; n = 4 from each group) or 14 weeks (20 weeks total; n = 4 from each group). Kidneys were analyzed by histomorphometry, and blood and urine samples were obtained to assess bone resorption. Whole-body and isolated femur Dual-Energy X-ray Absorptiometry (DEXA) scans were performed at the end of each study.
HSA
/LPS-treated animals developed a proliferative GN by 9 weeks, which is associated with proteinuria but no change in renal function. Between 9 and 20 weeks, there was evidence of an increasing interstitial inflammation (1381 +/- 67 interstitial cells/mm(2) at 9 weeks and 1818 +/- 28 interstitial cells/mm(2) at 20 weeks.) There was also evidence of bone resorbing activity as assessed by experimental/control (E/C) < 1.0 at 9 (E/C plasma = 0.66 +/- 0.05) and 20 (E/C plasma = 0.52 +/- 0.04) weeks. Parathyroid hormone (PTH) levels were normal at all time points, and no differences in bone mineral density were found. This model produces not only an immune glomerular/tubular injury, but also a stimulus for bone resorption that is related to objective measures of inflammation severity. The bone resorption is not caused by renal insufficiency, hyperparathyroidism, or steroid therapy. This model will prove useful in other studies of the role of renal inflammation in skeletal disorders.
...
PMID:Nonparathyroid hormone-mediated calcium resorption in a rat model of immune glomerulonephritis. 1613 56
We present the synthesis and structure of various protein nanotubes comprised of an alternate layer-by-layer (LbL) assembly using a polycation as an electrostatic glue. The nanotubes were fabricated by sequential LbL depositions of positively charged polycations and negatively charged proteins into a porous polycarbonate (PC) membrane, followed by release of the cylindrical core by quick dissolution of the template with CH(2)Cl(2). This procedure provides a variety of protein nanotubes without interlayer cross-linking. The three-cycle depositions of poly-L-arginine (PLA) and human serum albumin (
HSA
, M(w)=66.5 kDa) into the porous PC template (pore diameter, D(p)=400 nm) yielded well-defined (PLA/
HSA
)(3) nanotubes with an outer diameter of 419+/-29 nm and a wall thickness of 46+/-8 nm, revealed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations. The outer diameter of the tubules can be controlled by the pore size of the template (200-800 nm), whereas the wall thickness is always constant, independent of the D(p) value. The (PEI/
HSA
)(3) (PEI: polyethylenimine) nanotubes showed a slightly thin wall of 39+/-5 nm. CD spectra of the multilayered (PEI/
HSA
)(n) film on a flat quartz plate suggested that the secondary structure of
HSA
between the polycations was almost the same as that in aqueous solution. The three-cycle LbL depositions of PLA and
ferritin
(M(w)=460 kDa) or myoglobin (Mb, M(w)=1.7 kDa) into the porous PC membrane also gave cylindrical hollow structures. The wall thickness of the (PLA/
ferritin
)(3) and (PLA/Mb)(3) nanotubes were 55+/-5 nm and 31+/-4 nm; it depends on the globular size of the protein (ferritin>HSA>Mb). The individual
ferritin
molecule was clearly seen in the tubular walls by SEM and TEM measurements.
...
PMID:Protein nanotubes comprised of an alternate layer-by-layer assembly using a polycation as an electrostatic glue. 1881 57
Occupational asthma (OA) is a complex disease that is often hard to diagnose due to difficulties in detecting relevant exposure, along with inherent differences in disease susceptibility. Numerous studies have attempted to identify relevant biological and genetic markers for OA and to devise tools capable of detecting exposure to the causative agent. Immunological markers, including skin prick test reactivity and specific IgE and IgG antibodies can be used to detect high-molecular-weight allergens in cases of baker's asthma. For OA induced by low-molecular-weight agents, such as isocyanate, potential biomarkers include serum-specific IgE and IgG antibodies to isocyanate-
HSA
conjugate and IgG to cytokeratin 19 and transglutaminase-2. For protein-based markers,
ferritin
/transferrin and vitamin D-binding protein levels have been suggested for isocyanate-OA. Genetic markers of susceptibility to isocyanate-OA include human leukocyte antigen and CTNNA3. Further investigations will be needed to identify better biomarkers for OA, which may be used to inform clinical decision.
...
PMID:Biological and genetic markers in occupational asthma. 2543 Sep 50
Slow growing stationary phase bacteria are often tolerant to multiple stressors and antimicrobials. Here, we show that the pathogen Staphylococcus aureus develops a non-specific tolerance towards oxidative stress during the stationary phase, which is mediated by the nucleotide second messenger (p)ppGpp. The (p)ppGpp
0
mutant was highly susceptible to HOCl stress during the stationary phase. Transcriptome analysis of the (p)ppGpp
0
mutant revealed an increased expression of the PerR, SigB, QsrR, CtsR and HrcA regulons during the stationary phase, indicating an oxidative stress response. The (p)ppGpp
0
mutant showed a slight oxidative shift in the bacillithiol (
BSH
) redox potential (E
BSH
) and an impaired H
2
O
2
detoxification due to higher endogenous ROS levels. The increased ROS levels in the (p)ppGpp
0
mutant were shown to be caused by higher respiratory chain activity and elevated total and free iron levels. Consistent with these results, N-acetyl cysteine and the iron-chelator dipyridyl improved the growth and survival of the (p)ppGpp
0
mutant under oxidative stress. Elevated free iron levels caused 8 to 31-fold increased transcription of Fe-storage proteins
ferritin
(ftnA) and miniferritin (dps) in the (p)ppGpp
0
mutant, while Fur-regulated uptake systems for iron, heme or siderophores (efeOBU, isdABCDEFG, sirABC and sstADBCD) were repressed. Finally, the susceptibility of the (p)ppGpp
0
mutant towards the bactericidal action of the antibiotics ciprofloxacin and tetracycline was abrogated with N-acetyl cysteine and dipyridyl. Taken together, (p)ppGpp confers tolerance to ROS and antibiotics by down-regulation of respiratory chain activity and free iron levels, lowering ROS formation to ensure redox homeostasis in S. aureus.
...
PMID:The alarmone (p)ppGpp confers tolerance to oxidative stress during the stationary phase by maintenance of redox and iron homeostasis in Staphylococcus aureus. 3314 62
