Oleic acid-bound FABP7 drives glioma cell proliferation through regulation of nuclear lipid droplet formation.

Fatty acid-binding protein 7 (FABP7), one of the fatty acid (FA) chaperones involved in the modulation of intracellular FA metabolism, is highly expressed in glioblastoma, and its expression is associated with decreased patients' prognosis. Previously, we demonstrated that FABP7 requires its binding partner to exert its function and that a mutation in the FA-binding site of FABP7 affects tumour biology. Here, we explored the role of FA ligand binding for FABP7 function in tumour proliferation and examined the mechanism of FABP7 and ligand interaction in tumour biology. We discovered that among several FA treatment, oleic acid (OA) boosted cell proliferation of FABP7-expressing cells. In turn, OA increased FABP7 nuclear localization, and the accumulation of FABP7-OA complex in the nucleus induced the formation of nuclear lipid droplet (nLD), as well as an increase in colocalization of nLD with promyelocytic leukaemia (PML) nuclear bodies. Furthermore, OA increased mRNA levels of proliferation-related genes in FABP7-expressing cells through histone acetylation. Interestingly, these OA-boosted functions were abrogated in FABP7-knockout cells and mutant FABP7-overexpressing cells. Thus, our findings suggest that FABP7-OA intracellular interaction may modulate nLD formation and the epigenetic status thereby enhancing transcription of proliferation-regulating genes, ultimately driving tumour cell proliferation.

Macro and microanatomy of some organs of a juvenile male Ganges River dolphin (Platanista gangetica spp. gangetica).

Ganges River dolphins (Platanista gangetica spp. gangetica) are air-breathing, warm-blooded mammals endemic to the Ganges and Karnaphuli rivers of the Indian subcontinent. Nevertheless, very little basic histomorphological research has been conducted on this endangered species. Therefore, this study aimed to describe the morphological features of different organs of P. gangetica. Despite becoming aquatic animals, they showed similarities with terrestrial mammals, such as the pair of lungs and an apical bronchus in the respiratory system, which are pretty standard in ruminants and pigs. However, unlike the terrestrial animal, the tracheobronchial tree was stiffer due to circularly arranged anastomosing plates of the hyaline cartilaginous ring in the trachea, cartilaginous plates in the bronchiole, and thick alveolar septa. The digestive system showed a three-chambered mechanical and glandular stomach similar to the artiodactyles. However, the intestine showed smaller caecum like the monogastric mammal. The urogenital system showed lobulated kidneys, a urinary bladder, a fibroelastic penis with sigmoid flexure, and a long urethral process similar to some terrestrial ruminants. Considering the aquatic environment, all those modifications, unlike terrestrial mammals, are necessary for their adaptation. Thus, this research will broadly help our clinicians and conservationist to take further steps toward disease diagnosis and monitoring of marine health of this endangered species.

Nuclear FABP7 regulates cell proliferation of wild-type IDH1 glioma through caveolae formation.

Isocitrate dehydrogenase 1 (IDH1) is a key enzyme in cellular metabolism. IDH1 mutation (IDH1mut) is the most important genetic alteration in lower grade glioma, whereas glioblastoma (GB), the most common malignant brain tumor, often has wild-type IDH1 (IDH1wt). Although there is no effective treatment yet for neither IDH1wt nor IDHmut GB, it is important to note that the survival span of IDH1wt GB patients is significantly shorter than those with IDH1mut GB. Thus, understanding IDH1wt GB biology and developing effective molecular-targeted therapies is of paramount importance. Fatty acid-binding protein 7 (FABP7) is highly expressed in GB, and its expression level is negatively correlated with survival in malignant glioma patients; however, the underlying mechanisms of FABP7 involvement in tumor proliferation are still unknown. In this study, we demonstrate that FABP7 is highly expressed and localized in nuclei in IDH1wt glioma. Wild-type FABP7 (FABP7wt) overexpression in IDH1wt U87 cells increased cell proliferation rate, caveolin-1 expression, and caveolae/caveosome formation. In addition, FABP7wt overexpression increased the levels of H3K27ac on the caveolin-1 promoter through controlling the nuclear acetyl-CoA level via the interaction with ACLY. Consistent results were obtained using a xenograft model transplanted with U87 cells overexpressing FABP7. Interestingly, in U87 cells with mutant FABP7 overexpression, both in vitro and in vivo phenotypes shown by FABP7wt overexpression were disrupted. Furthermore, IDH1wt patient GB showed upregulated caveolin-1 expression, increased levels of histone acetylation, and increased levels of acetyl-CoA compared with IDH1mut patient GB. Taken together, these data suggest that nuclear FABP7 is involved in cell proliferation of GB through caveolae function/formation regulated via epigenetic regulation of caveolin-1, and this mechanism is critically important for IDH1wt tumor biology.

Ndufs4 ablation decreases synaptophysin expression in hippocampus.

Altered function of mitochondrial respiratory chain in brain cells is related to many neurodegenerative diseases. NADH Dehydrogenase (Ubiquinone) Fe-S protein 4 (Ndufs4) is one of the subunits of mitochondrial complex I and its mutation in human is associated with Leigh syndrome. However, the molecular biological role of Ndufs4 in neuronal function is poorly understood. In this study, upon Ndufs4 expression confirmation in NeuN-positive neurons, and GFAP-positive astrocytes in WT mouse hippocampus, we found significant decrease of mitochondrial respiration in Ndufs4-KO mouse hippocampus. Although there was no change in the number of NeuN positive neurons in Ndufs4-KO hippocampus, the expression of synaptophysin, a presynaptic protein, was significantly decreased. To investigate the detailed mechanism, we silenced Ndufs4 in Neuro-2a cells and we observed shorter neurite lengths with decreased expression of synaptophysin. Furthermore, western blot analysis for phosphorylated extracellular regulated kinase (pERK) revealed that Ndufs4 silencing decreases the activity of ERK signalling. These results suggest that Ndufs4-modulated mitochondrial activity may be involved in neuroplasticity via regulating synaptophysin expression.

Ligand Bound Fatty Acid Binding Protein 7 (FABP7) Drives Melanoma Cell Proliferation Via Modulation of Wnt/ß-Catenin Signaling.

PURPOSE: Fatty acid-binding protein 7 (FABP7) involved in intracellular lipid dynamics, is highly expressed in melanomas and associated with decreased patient survival. Several studies put FABP7 at the center of melanoma cell proliferation. However, the underlying mechanisms are not well deciphered. This study examines the effects of FABP7 on Wnt/ß-catenin signaling that enhances proliferation in melanoma cells. METHODS: Skmel23 cells with FABP7 silencing and Mel2 cells overexpressed with wild-type FABP7 (FABP7wt) and mutated FABP7 (FABP7mut) were used. Cell proliferation and migration were analyzed by proliferation and wound-healing assay, respectively. Transcriptional activation of the Wnt/ß-catenin signaling was measured by luciferase reporter assay. The effects of a specific FABP7 inhibitor, MF6, on proliferation, migration, and modulation of the Wnt/ß-catenin signaling were examined. RESULTS: FABP7 siRNA knockdown in Skmel23 decreased proliferation and migration, cyclin D1 expression, as well as Wnt/ß-catenin activity. Similarly, FABP7wt overexpression in Mel2 cells increased these effects, but FABP7mut abrogated these effects. Pharmacological inhibition of FABP7 function with MF6 suppressed FABP7-regulated proliferation of melanoma cells. CONCLUSION: These results suggest the importance of the interaction between FABP7 and its ligands in melanoma proliferation modulation, and the beneficial implications of therapeutic targeting of FABP7 for melanoma treatment.

Mitochondrial dysfunction in GnRH neurons impaired GnRH production.

The onset establishment and maintenance of gonadotropin-releasing hormone (GnRH) secretion is an important phenomenon regulating pubertal development and reproduction. GnRH neurons as well as other neurons in the hypothalamus have high-energy demands and require a constant energy supply from their mitochondria machinery to maintain active functioning. However, the involvement of mitochondrial function in GnRH neurons is still unclear. In this study, we examined the role of NADH Dehydrogenase (Ubiquinone) Fe-S protein 4 (Ndufs4), a member of the mitochondrial complex 1, on GnRH neurons using Ndufs4-KO mice and Ndufs4-KO GT1-7 cells. Ndufs4 was highly expressed in GnRH neurons in the medial preoptic area (MPOA) and NPY/AgRP and POMC neurons in the arcuate (ARC) nucleus in WT mice. Conversely, there was a significant decrease in GnRH expression in MPOA and median eminence of Ndufs4-KO mice, followed by impaired peripheral endocrine system. In Ndufs4-KO GT1-7 cells, Gnrh1 expression was significantly decreased with or without stimulation with either kisspeptin or NGF, whereas, stimulation significantly increased Gnrh1 expression in control cells. In contrast, there was no difference in cell signaling activity including ERK and CREB as well as the expression of GPR54, TrkA and p75NTR, suggesting that Ndufs4 is involved in the transcriptional regulation system for GnRH production. These findings may be useful in understanding the mitochondrial function in GnRH neuron.

FABP7 Regulates Acetyl-CoA Metabolism Through the Interaction with ACLY in the Nucleus of Astrocytes.

Fatty acid binding protein 7 (FABP7) is an intracellular fatty acid chaperon that is highly expressed in astrocytes, oligodendrocyte-precursor cells, and malignant glioma. Previously, we reported that FABP7 regulates the response to extracellular stimuli by controlling the expression of caveolin-1, an important component of lipid raft. Here, we explored the detailed mechanisms underlying FABP7 regulation of caveolin-1 expression using primary cultured FABP7-KO astrocytes as a model of loss of function and NIH-3T3 cells as a model of gain of function. We discovered that FABP7 interacts with ATP-citrate lyase (ACLY) and is important for acetyl-CoA metabolism in the nucleus. This interaction leads to epigenetic regulation of several genes, including caveolin-1. Our novel findings suggest that FABP7-ACLY modulation of nuclear acetyl-CoA has more influence on histone acetylation than cytoplasmic acetyl-CoA. The changes to histone structure may modify caveolae-related cell activity in astrocytes and tumors, including malignant glioma.

The role of fatty acid binding protein 7 in spinal cord astrocytes in a mouse model of experimental autoimmune encephalomyelitis.

Fatty acid binding protein 7 (FABP7) is expressed in astrocytes of the developing and mature central nervous system, and modulates astrocyte function by controlling intracellular fatty acid homeostasis. Astrocytes in the spinal cord have an important role in the process of myelin degeneration and regeneration. In the present study, the authors examined the role of FABP7 in astrocytes in a mouse model of experimental autoimmune encephalomyelitis (EAE), which is an established model of multiple sclerosis (MS). FABP7 was expressed in the white matter astrocytes and increased after EAE onset; particularly strong expression was observed in demyelinating regions. In FABP7-knockout (KO) mice, the onset of EAE symptoms occurred earlier than in wild type (WT) mice, and mRNA expression levels of inflammatory cytokines (IL-17 and TNF-α) were higher in FABP7-KO lumbar spinal cord than in WT lumbar spinal cord at early stage of EAE. Interestingly, however, the clinical score was significantly reduced in FABP7-KO mice compared with WT mice in the late phase of EAE. Moreover, the area exhibiting expression of fibronectin, which is an extracellular matrix protein mainly produced by astrocytes and inhibits remyelination of oligodendrocytes, was significantly decreased in FABP7-KO compared with WT mice. Collectively, FABP7 in astrocyte may have a role to protect from the induction of inflammation leading to demyelination in CNS at early phase of EAE. Moreover, FABP7 may be involved in the regulation of fibronectin production through the modification of astrocyte activation at late phase of EAE.

FABP7 Protects Astrocytes Against ROS Toxicity via Lipid Droplet Formation.

Fatty acid-binding proteins (FABPs) bind and internalize long-chain fatty acids, controlling lipid dynamics. Recent studies have proposed the involvement of FABPs, particularly FABP7, in lipid droplet (LD) formation in glioma, but the physiological significance of LDs is poorly understood. In this study, we sought to examine the role of FABP7 in primary mouse astrocytes, focusing on its protective effect against reactive oxygen species (ROS) stress. In FABP7 knockout (KO) astrocytes, ROS induction significantly decreased LD accumulation, elevated ROS toxicity, and impaired thioredoxin (TRX) but not peroxiredoxin 1 (PRX1) signalling compared to ROS induction in wild-type astrocytes. Consequently, activation of apoptosis signalling molecules, including p38 mitogen-activated protein kinase (MAPK) and stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK), and increased expression of cleaved caspase 3 were observed in FABP7 KO astrocytes under ROS stress. N-acetyl L-cysteine (NAC) application successfully rescued the ROS toxicity in FABP7 KO astrocytes. Furthermore, FABP7 overexpression in U87 human glioma cell line revealed higher LD accumulation and higher antioxidant defence enzyme (TRX, TRX reductase 1 [TRXRD1]) expression than mock transfection and protected against apoptosis signalling (p38 MAPK, SAPK/JNK and cleaved caspase 3) activation. Taken together, these data suggest that FABP7 protects astrocytes from ROS toxicity through LD formation, providing new insights linking FABP7, lipid homeostasis, and neuropsychiatric/neurodegenerative disorders, including Alzheimer's disease and schizophrenia.

Role of FABP7 in tumor cell signaling.

Lipids are major molecules for the function of organisms and are involved in the pathophysiology of various diseases. Fatty acids (FAs) signaling and their metabolism are some of the most important pathways in tumor development, as lipids serve as energetic sources during carcinogenesis. Fatty acid binding proteins (FABPs) facilitate FAs transport to different cell organelles, modulating their metabolism along with mediating other physiological activities. FABP7, brain-typed FABP, is thought to be an important molecule for cell proliferation in healthy as well as diseased organisms. Several studies on human tumors and tumor-derived cell lines put FABP7 in the center of tumorigenesis, and its high expression level has been reported to correlate with poor prognosis in different tumor types. Several types of FABP7-expressing tumors have shown an up-regulation of cell signaling activity, but molecular mechanisms of FABP7 involvement in tumorigenesis still remain elusive. In this review, we focus on the expression and function of FABP7 in different tumors, and possible mechanisms of FABP7 in tumor proliferation and migration.

Macroanatomy of the ones of thoracic limb of an Asian elephant (Elephas maximus) / Macroanatomía de los huesos del miembro torácico de un elefante asiático (Elephas maximus)

Bones of forelimb were studied from a prepared skeleton of an adult female Asian elephant (Elephas maximus) in Anatomy Museum of Chittagong Veterinary and Animal Sciences University to understand the morphological form and structure of Asian elephant forelimb. The angle was approximately 123 between caudal border of scapula and caudal border of humerus. The scapula, humerus and bones of the antebrachium (particularly the ulna) were massive bones. The bones of manus were the short and relatively small. The dorsal border of scapula extended from the level of proximal extremity of first rib to the middle of the 6th rib. Ventral angle of scapula articulated with humerus by elongated shaped glenoid cavity (cavitas glenoidalis) of scapula and head of humerus (caput humeri). The major tubercle (tuberculum majus) of humerus was situated laterally to the head, which had smaller cranial part with large caudal part and extended cranially to the head. The crest of minor tubercle (tuberculum minus) was present as the rough line on the mediocaudal surface of humerus that ends in a slight depressed or elevated area, known as teres major tuberosity (tuberositas teres major). The lateral supracondyler crest (crista supra condylaris lateralis) at the caudal surface of the shaft limit the musculo-spiral groove in body of humerus. The radius and ulna are twin bones of forearm and the attachment between ulna and radius occurs in such a way, the radius articulates craniomedially with the ulna in the proximal part. But the shaft spirals laterally over the cranial surface of the ulna to articulate distally with the medial aspect of the ulna. There were 8 carpal bones, 5 metacarpal bones and 5 digits. The comparative size of the proximal and distal raw of carpal bones were ulnar carpal > radial > intermediate > accessory carpal and IV > III > II > I respectively. The gradual lengths of the metacarpal bones were III > IV > II > V > I. Digits I and V were vertical and digit II, III and IV were horizontal.

En el Museo de Anatomía de la Universidad de Veterinaria y Ciencias de Animales de Chittagong fueron estudiados los huesos del miembro torácico de un esqueleto preparado de un elefante asiático (Elephas maximus), hembra adulta, para analizar su morfología y estructura. El ángulo entre el margen caudal de la escápula y el margen caudal del húmero era de aproximadamente 123°. La escápula, húmero y los huesos del antebrazo (en particular la ulna) eran huesos macizos. Los huesos de las manos eran cortos y relativamente pequeños. El margen dorsal de la escápula se extendía desde el nivel de la porción proximal de la primera costilla para la parte media de la sexta costilla. El ángulo ventral de la escápula está articulado con el húmero por la cavidad glenoidea (cavitas glenoidalis), de forma alargada, de la escápula y la cabeza del húmero (caput humeri). El principal tubérculo (tuberculum majus) del húmero estaba situado lateralmente a la cabeza, que tenía una parte craneal pequeña y una mayor parte caudal, extendiéndose cranealmente en la cabeza. La cresta del tubérculo menor (tuberculum minus) estaba presente como la línea áspera sobre la superficie mediocaudal del húmero que termina en una pequeña zona deprimida o elevada, conocida como tuberosidad redonda mayor (tuberositas teres major). La cresta supracondilar lateral (crista supra condylaris lateralis) en la superficie caudal del eje limita la ranura músculo-espiral en el húmero. El radio y la ulna son huesos gemelos del antebrazo y la unión entre la ulna y el radio se produce de tal manera, que el radio articula, craneal y medialmente, con la ulna en la porción proximal. Pero el eje en espiral está ubicado lateralmente sobre la superficie craneal de la ulna para articular distalmente con la cara medial de la ulna. Se identificaron 8 huesos del carpo, 5 metacarpianos y 5 dígitos. El tamaño comparativo de las porciones proximal y distal de los huesos del carpo fue ulna > radial > Intermedio> carpiano accesorio y IV > III > II > I, respectivamente. Las longitudes graduales de los huesos metacarpianos eran III > IV > II > V > I. Dígitos I y V eran verticales y dígitos II, III y IV fueron horizontales.

Histological and morphometric analysis of testes of adult quail (Coturnix coturnix japonica) of Bangladesh / Análisis histológico y morfométrico de testiculos de codorniz adulta (Coturnix coturnix japonica) de Bangladesh

A histological and morphometric study was conducted to evaluate the seasonal testicular variations in the adult Japanese quail (Coturnix coturnix japonica) in Bangladesh. The weight of birds and testes, volume, length, circumference, seminiferous tubule diameter, circumference and height of germinal epithelium of testes were measured. Sections of testes obtained from studied birds were stained with H&E and images were taken by J software. Weight and volume of paired testes of quails significantly heavier (P<0.05) in long day period of summer and rainy season (March ­ September) than the short day period of autumn and winter (October ­ February). Seasons had no significant effect on live weight gain of quails. The weight and diameter of testes or height of the germinal epithelium of the seminiferous tubule were positively correlated (r=0.84; r=0.88). Spermatogenic activity was pronounced during summer and rainy season than that of autumn and winter (P<0.05).

Se realizó un estudio histológico y morfométrico para evaluar las variaciones testiculares estacionales de la codorniz japonesa adulta (Coturnix coturnix japonica) en Bangladesh. Se midieron el peso de las aves y sus testículos; el volumen, longitud, circunferencia y diámetro de los túbulos seminíferos, y la circunferencia y altura del epitelio germinal testicular. Secciones de testículos obtenidos de las aves estudiadas fueron teñidas con H&E y las imágenes fueron analizadas con el programa ImageJ. Se registró un aumento significativo en peso y volumen de los testículos de codornices (P<0,05) en el periodo día de verano y en la temporada de lluvia (marzo-septiembre) al período del día corto de otoño e invierno (octubre-febrero). El período estacionario no tuvo efecto significativo sobre el aumento de peso vivo de las codornices. El peso y el diámetro de los testículos, y la altura del epitelio germinal del túbulo seminífero se correlacionaron positivamente (r=0,84; r=0,88). La actividad espermatogénica fue más pronunciada durante el verano y durante la temporada de lluvias que en otoño e invierno (p<0,05).

Macroanatomy of the bones of pelvis and hind limb of an asian elephant (elephas maximus) / Macroanatomía de los huesos de la pelvis y del miembro posterior de un elefante asiático (elephas maximus)

Recent excavated skeleton of an adult female Asian Elephant (Elephas maximus), died in dystokia in Bangladesh was used for macro anatomical study. Some unique morphological features of bones of hind limb were observed. Pelvic canal was more oval and the wings of ilium were wider. Rump slope was about 36°. Angle between femur and tibia was close to 180°. In Femur, the major trochanter was located at the lower level of head. Minor trochanter, fovea capitis and trochanteric ridge were absent. Supracondyloid fossa was shallow but the intercondyloid fossa was deep. Posterior surface of patella possessed a blunt vertical ridge. The articular surfaces of both tibial condyles were clearly concave. The tibia and the fibula were articulated proximally and distally with keeping a wide interosseous space. Instead of tibial tuberosity, there was an elongated triangular depression in proximal part. There were six tarsal bones arranged in three rows. The comparative size of the distal tarsal bones were III+IV > I > II. The comparative lengths of the metatarsal bones were III > II > IV > V> I. Digits I and V were the most vertical and digit III was the most horizontal. The proximal phalanx was the biggest of all.

Fue utilizado para su estudio anatómico macrocroscópico, el esqueleto de un elefante asiático (Elephas maximus) hembra adulta, excavado recientemente y con muerte por distocia en Bangladesh. Se observaron algunas características morfológicas únicas de los huesos de los miembros posteriores. El canal pélvico era más ovalado y las alas del ilion eran más amplias. La pendiente de la rabadilla era de unos 36° aproximadamente; el ángulo entre el fémur y la tibia era próximo a los 180°. En el fémur, el trocánter mayor se encontraba en el nivel inferior de la cabeza. El trocánter menor, la fovea capitis y cresta del trocánter estuvieron ausentes. La fosa supracondílea era superficial, mientras que la fosa intercondílea era profunda. La superficie posterior de la patela poseía una cresta vertical sobresaliente. Las superficies articulares de ambos cóndilos tibiales eran claramente cóncavas. La tibia y la fíbula se articulan proximal y distalmente, manteniendo un amplio espacio interóseo. En lugar de la tuberosidad tibial, había una depresión triangular alargada en parte proximal. Se observaron seis huesos del tarso dispuestos en tres filas. El tamaño relativo de los huesos del tarso distal eran III + IV > I > II. Las longitudes comparativas de los huesos metatarsianos fueron III > II > IV > V > I. Los dígitos I y V fueron los más verticales y el dígito III fue el más horizontal. La falange proximal fue la de mayor tamaño.