Development of Auer bodies from giant inclusions associated with rough endoplasmic reticulum in acute promyelocytic leukemia

Giant inclusions and Auer bodies in promyeloblasts were investigated in a study which included transmission electron microscopy(TEM)for morphology and ultrastructural cytochemistry for myeloperoxidase in 10 patients with acute promyelocytic leukemia(APL).Ultrastructural cytochemistry demonstrated positive myeloperoxidase reactivity in giant inclusions,expanded rER cisternae,Auer bodies and primary granules.TEM revealed that giant inclusions were adorned by degenerated rER membrane,some of them sharing features with Auer bodies.We hypothesize a novel origin for Auer body development in promyeloblasts of APL,namely that they originate from peroxidase-positive and expanded rER cisternae,and that primary granules were directly released from these expanded rER elements,bypassing the Golgi apparatus.

Bone marrow mesenchymal cells: polymorphism associated with transformation of rough endoplasmic reticulum

To understand the behavior and function of bone-marrow mesenchymal cells(BMMCs),we overviewed the morphological presentation of BMMCs in bone-marrow granules(b-BMMCs),isolated BMMCs(i-BMMCs),and BMMCs(c-BMMCs)cultured in H4434 methylcellulose semisolid and MEM media.All samples were derived from bone-marrow aspirates of 30 patients with hematocytopenia.Light microscopy exhibited b-BMMCs and i-BMMCs characterized by abundant cytoplasm and irregular shape in bone-marrow smears,as well as c-BMMCs in culture conditions.Scanning electron microscopy demonstrated cultured c-BMMCs with a sheet-like feature enveloping hematopoietic cells.Transmission electron microscopy revealed b-BMMCs constructing a honeycomb-like structure by thin bifurcate processes among hematopoietic cells.Furthermore,i-BMMCs had bifurcate parapodiums on the surface and prominent rough endoplasmic reticulum(rER)connected with the plasmalemma of the parapodiums.The detailed images suggested that rER may serve as a membrane resource for plasmalemmal expansion in BMMCs in bone marrow.

Repeated febrile convulsions impair hippocampal neurons and cause synaptic damage in immature rats: neuroprotective effect of fructose-1,6-diphosphate

Fructose-1,6-diphosphate is a metabolic intermediate that promotes cell metabolism. We hypothesize that fructose-1,6-diphosphate can protect against neuronal damage induced by febrile convulsions. Hot-water bathing was used to establish a repetitive febrile convulsion model in rats aged 21 days, equivalent to 3–5 years in humans. Ninety minutes before each seizure induction, rats received an intraperitoneal injection of low- or high-dose fructose-1,6-diphosphate（500 or 1,000 mg/kg, respectively）. Low- and high-dose fructose-1,6-diphosphate prolonged the latency and shortened the duration of seizures. Furthermore, high-dose fructose-1,6-diphosphate effectively reduced seizure severity. Transmission electron microscopy revealed that 24 hours after the last seizure, high-dose fructose-1,6-diphosphate reduced mitochondrial swelling, rough endoplasmic reticulum degranulation, Golgi dilation and synaptic cleft size, and increased synaptic active zone length, postsynaptic density thickness, and synaptic interface curvature in the hippocampal CA1 area. The present findings suggest that fructose-1,6-diphosphate is a neuroprotectant against hippocampal neuron and synapse damage induced by repeated febrile convulsion in immature rats.

Peripheral nerve axons contain machinery for co-translational secretion of axonally-generated proteins

The axonal compartment of developing neurons and mature peripheral nervous system （PNS） neurons has the capacity to locally synthesize proteins. Axonally-synthesized proteins have been shown to facilitate axonal pathfinding and maintenance in developing central nervous system （CNS） and PNS neurons, and to facilitate the regeneration of mature PNS neurons. RNA-profiling studies of the axons of cultured neurons have shown a surprisingly complex population of mRNAs that encode proteins for a myriad of functions. Although classic-appearing rough endoplasmic reticulum （RER）, smooth endoplasmic reticulum （ER） and Golgi apparatus have not been documented in axons by ultrastructural studies, axonal RNA profiling studies show several membrane and secreted protein-encoding mRNAs whose translation products would need access to a localized secretory mechanism. We previously showed that the axons of cultured neurons contain functional equivalents of RER and Golgi apparatus. Here, we show that markers for the signal-recognition particle, RER, ER, and Golgi apparatus are present in PNS axons in vivo. Co-localization of these proteins mirrors that seen for cultured axons where locally-translated proteins are localized to the axoplasmic membrane. Moreover, nerve injury increases the levels and/or aggregation of these proteins, suggesting that the regenerating axon has an increased capacity for membrane targeting of locally synthesized proteins.