Circadian Locomotor Research Articles

Abstract 669: Interrogating circadian clock compounds as an adjuvant to chemoradiation against GBM

Abstract Despite the extensive efforts of researchers and physicians over the past two decades, glioblastoma (GBM) remains the most prevalent brain tumor type with a grim average survival time of 8 months following diagnosis irrespective of treatment. Additionally, the current standard-of-care has not changed from maximal surgical resection followed by concurrent chemoradiation from its establishment in 2005. One of the major challenges that limits progress in treating GBM is the presence of GBM stem cells (GSCs) that are highly invasive, reaching far past the tumor margins, are resistant to both chemotherapy and radiation, and can recapitulate the primary tumor following resection. Recent studies have found that GSCs, however, are highly sensitive to targeting of core circadian clock components, particularly positive regulators of the clock Brain and Muscle ARNTL-Like 1 (BMAL1) and Circadian Locomoter Output Cycles Protein Kaput (CLOCK). Here we employ the use of small molecule compounds that upregulate the activity of the negative regulators of the clock in order to suppress BMAL1::CLOCK transcriptional activity or repress BMAL1 transcription. We find that these compounds not only have a much more potent effect against GSCs compared to temozolomide (TMZ) chemotherapy but also, they display combination effect against both GSCs and differentiated GSCs (DGCs) when combined with TMZ. These results suggest that the blood brain barrier (BBB) penetrant circadian clock compounds can be utilized as an adjuvant to current GBM therapies as they can effectively target both the primary tumor cells and GSCs. Citation Format: Priscilla Chan, Qiulian Wu, Anahit Hovsepyan, Seda Mkhitaryan, Gevorg Karapetyan, Khalid Shah, Hiroaki Wakimoto, Theodore Kamenecka, Laura A. Solt, Jamie Cope, Tsuyoshi Hirota, Rex A. Moats, Jeremy N. Rich, Steve A. Kay. Interrogating circadian clock compounds as an adjuvant to chemoradiation against GBM [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 669.

DDDR-07. TARGETING THE CIRCADIAN CLOCK WITH SMALL MOLECULE COMPOUNDS RESULTS IN ANTI-TUMOR EFFECTS SPECIFICALLY IN GLIOBLASTOMA STEM CELLS

Abstract Glioblastoma multiforme (GBM) is the most common primary brain tumor, with an average survival time of less than one year following diagnosis. Treatment success remains challenging despite aggressive, multimodal current standard-of-care consisting of maximal surgical resection followed by concurrent temozolomide (TMZ) chemotherapy and radiation. The presence of GBM stem cells (GSCs) is thought to make treatment exceptionally difficult as they are highly invasive, resistant to chemoradiation, promote angiogenesis, support an immune suppressive environment, and can recapitulate the primary tumor following surgical resection. We have reported that GSCs, however, are dependent on core circadian clock proteins, Brain and Muscle ARNTL-Like 1 (BMAL1) and Circadian Locomoter Output Cycles Protein Kaput (CLOCK), which is not observed in differentiated GBM cells or normal neuronal stem cells. In this study, we explore the anti-GSC effects of multiple families of novel small molecule circadian clock compounds that either lower BMAL1 transcription (REV-ERB agonists) or inhibit BMAL1::CLOCK heterodimer transcriptional activity (Cryptochrome (CRY) stabilizers or Casein Kinase (CK) 1/2 inhibitors). Here we report that compared to compared to non-cancerous cells, U2OS human osteosarcoma cells, and differentiated GSCs (DGCs), GSCs display increased sensitivity to clock compounds at single agent and combinatory doses of clock compounds. Additionally, clock compounds are significantly more effective in targeting GSCs than TMZ and combinations of clock compounds with TMZ can lower TMZ IC50 value in different GBM cell lines and types. Application of the CRY stabilizer SHP1705 in GBM PDX patient derived xenograft (PDX) models resulted in decreased tumor growth rate and increased survival time compared to vehicle control. These results highlight the therapeutic potential of circadian clock compounds as single agents, in combinations and as adjuvants to existing therapies by specifically targeting the GSC population in GBM.

Transcriptome sequencing of the central nervous system to identify the neuropeptides and neuropeptide receptors of Antheraea pernyi

Neuropeptides and neuropeptide receptors are crucial regulators for the behavior, lifecycle, and physiology of insects and are mainly produced and released from the neurosecretory cells of the central nervous system (CNS). In this study, RNA-seq was employed to investigate the transcriptome profile of the CNS which is composed of the brain and ventral nerve cord (VNC) of Antheraea pernyi. From the data sets, a total of 18 and 42 genes were identified, which respectively encode the neuropeptides and neuropeptide receptors involved in regulating multiple behaviors including feeding, reproductive behavior, circadian locomotor, sleep, and stress response and physiological processes such as nutrient absorption, immunity, ecdysis, diapause, and excretion. Comparison of the patterns of expression of those genes between the brain and VNC showed that most had higher levels of expression in the brain than VNC. Besides, 2760 differently expressed genes (DEGs) (1362 up-regulated and 1398 down-regulated ones between the B and VNC group) were also screened and further analyzed via gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) enrichment analyses. The results of this study could provide comprehensive profiles of the neuropeptides and neuropeptide receptors of A. pernyi CNS and lay the foundation for further research into their functions.

Chronobiological aspects of the anti-stress effect of anxiolytics

BACKGROUND: A stressful event, being a disturbing factor, is invariably accompanied by the disorganization of biological rhythms.
 AIM: To examine the effects of stress and pharmacological substances on two models of the temporal organization of behavior, i.e., circadian locomotion and swimming dynamics in rats.
 MATERIALS AND METHODS: The daily dynamics of rat mobility were assessed in a specially designed device consisting of living cells connected to a computer. Each cell is connected by a lever and a hinge with a button. When the rat moved from one end of the box to the other, the contact was closed, and the program autonomously summed up the number of such movements for each hour of the experiment. The total number of transitions was counted in 3 h, followed by the construction of a chronogram of the circadian rhythm of mobility. To assess the effect of substances on the circadian rhythm, anxiolytics diazepam (0.1 mg/kg), tofisopam (10 mg/kg), and epiphyseal hormone melatonin (0.1 mg/kg) were injected intraperitoneally into rats. Rats that received the same volume of saline injections (0.5 mL) served as controls.
 RESULTS: Substances with anxiolytic properties, benzodiazepine derivatives diazepam (0.1 mg/kg) and tofisopam (10 mg/kg), and epiphyseal hormone melatonin (0.1 mg/kg), similarly eliminated stress-induced dysrhythmia in rats. Under their influence, the circadian rhythm of motor activity was normalized, and adaptive shifts were observed in the temporal dynamics of forced swimming.
 CONCLUSION: A single stressful event disrupts the dynamics of daily mobility in rats. Diazepam, tofisopam, and melatonin, while differing in potency, generally alleviate these disorders. In particular, anxiolytics restore the rhythm in animals highly sensitive to stress. The studied substances reorganized the temporal dynamics in rats subjected to forced swimming and increased the proportion of long-period oscillations. Primary or secondary elimination of stress dysrhythmia is an important factor in the specific action of anxiolytics.

Abstract 505: Small molecule circadian clock compounds display therapeutic potential in targeting glioblastoma stem cells

Abstract Glioblastoma multiforme (GBM) is the most common primary brain tumor, claiming the lives of roughly 10,000 Americans each year. Despite being the first cancer analyzed through the Cancer Genome Atlas, treatment success remains minimal, resulting average survival time of patients is 15 months following diagnosis and a five-year survival rate is 6.8%. One of the major challenges in treating GBM is the presence of GBM stem cells (GSCs) that are resistant to temozolomide (TMZ) chemotherapy and radiation, which is part of the current standard of care for GBM following maximal surgical resection. We found, however, that GSCs have a unique dependence on core circadian clock proteins, Brain and Muscle ARNTL-Like 1 (BMAL1) and Circadian Locomoter Output Cycles Protein Kaput (CLOCK), which is not observed in differentiated GBM cells or normal neuronal stem cells. Here we explore the use of novel small molecule circadian clock compounds that either lower BMAL1 transcription (REV-ERB agonists) or inhibit BMAL1::CLOCK heterodimer transcriptional activity (Cryptochrome (CRY) stabilizers or Casein Kinase (CK) 1/2 inhibitors) in targeting GSCs in in vitro patient derived cell lines and in in vivo GBM patient-derived xenograft (PDX) models. GSCs display increased sensitivity to clock compounds at single agent and combinations of clock compounds compared to non-cancerous cells, U2OS human osteosarcoma cells, and differentiated GSCs. Additionally, clock compounds are significantly more effective in targeting GSCs than TMZ. The clock compound SHP1705 increased over survival and delayed tumor growth in GBM PDX models. These results highlight the therapeutic potential small molecule circadian clock compounds have against GBM as both a single agent and adjuvant to existing therapies by specifically targeting the GSC population. Citation Format: Priscilla Chan, Lian Wu, Anahit Hovsepyan, Seda Mkhitaryan, Gevorg Karapetyan, Khalid Shah, Hiroaki Wakimoto, Theodore Kamenecka, Laura A. Solt, Jamie Cope, Rex A. Moats, Tsuyoshi Hirota, Jeremy N. Rich, Steve A. Kay. Small molecule circadian clock compounds display therapeutic potential in targeting glioblastoma stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 505.

CLOCK 3111TT Genotype Is Associated with Increased Total Cholesterol and Low-Density Lipoprotein Levels in Menopausal Women with a Body Mass Index of at Least 25 kg/m2.

Lipid profile comparative analysis was performed to reveal the interdependence of lipids with Circadian locomoter output cycles protein kaput (CLOCK) 3111T/C gene polymorphism in menopausal women with/without a body mass index (BMI) of ≥25 kg/m2. Methods: A total of 193 female volunteers aged 45 to 60 years were divided into two groups: Those with BMI < 25 kg/m2 (control) and those with BMI ≥ 25 kg/m2. Each group was then divided into two subgroups: Those with the CLOCK TT-genotype and those with the CLOCK TC-, CC-genotypes. Lipid metabolism parameters were determined by the enzymatic method. Single-nucleotide polymorphisms (SNPs) were detected via polymerase chain reaction–restriction fragment length polymorphism technology. Results: There were no differences in CLOCK 3111T/C genotypes or allele frequency between the control and main groups. In addition, there were no differences in lipid profile parameters between women of the control group and different CLOCK 3111T/C genotypes. The total cholesterol (p = 0.041) and low-density lipoprotein cholesterol (p = 0.036) levels were higher in the subgroup of women with a BMI ≥ 25 kg/m2 and CLOCK TT-genotype as compared to the subgroup with a BMI ≥ 25 kg/m2 and minor allele 3111C. Conclusions: SNP 3111T/C of the CLOCK gene is not associated with BMI however, data suggest that the minor allele of the CLOCK 3111T/C gene polymorphism may have a protective role in atherogenic lipid levels in women with a BMI greater than or equal to 25 kg/m2.

Post-embryonic Development of the Circadian Clock Seems to Correlate With Social Life Style in Bees.

Social life style can influence many aspects of an animal’s daily life, but it has not yet been clarified, whether development of the circadian clock in social and solitary living bees differs. In a comparative study, with the social honey bee, Apis mellifera, and the solitary mason bee, Osmia bicornis, we now found indications for a differentially timed clock development in social and solitary bees. Newly emerged solitary bees showed rhythmic locomotion right away and the number of neurons in the brain that produce the clock component pigment-dispersing factor (PDF) did not change during aging of the adult solitary bee. Honey bees on the other hand, showed no circadian locomotion directly after emergence and the neuronal clock network continued to grow after emergence. Social bees appear to emerge at an early developmental stage at which the circadian clock is still immature, but bees are already able to fulfill in-hive tasks.

Implications of the circadian clock in implant dentistry.

Circadian rhythms are approximately 24-h cell-autonomous cycles driven by transcription and translation feedback loops of a set of core circadian clock genes, such as circadian locomoter output cycles kaput (Clock), brain and muscle arnt-like protein-1 (Bmal1), period (Per), and cryptochrome (Cry). The genetic clockwork of these genes produces circadian rhythms in cells throughout the body, including the craniofacial region. During development, dento-alveolar bone tissue formation could be regulated by site-specific circadian patterns. Studies using knockout mice and mesenchymal stem cells (MSCs) to evaluate clock genes revealed regulatory effects of clock function on bone remodeling, suggesting involvement of the circadian clockwork in osseointegration of titanium implants. Indeed, rough surface titanium modulates specific clock genes, Neuronal PAS domain protein-2 (Npas2) and Per, in MSCs to facilitate osseointegration. Further understanding of the bone clock machinery associated with biomaterial surface properties might improve preoperative diagnosis for dental implant treatments.

Serotonin Prevents Differentiation of Brown Adipocytes by Interfering with Their Clock.

Serotonin was shown to interfere with the differentiation of brown adipocytes. In addition, clock components inhibit brown adipogenesis through direct transcriptional control of key components of the transforming growth factor β pathway. The aim of this study was to investigate whether serotonin abrogates brown adipogenesis by affecting clock functionality. Nondifferentiated and differentiated HIB1B brown adipocytes were treated with serotonin, and their clock expression and functionality and differentiation state were examined. Nondifferentiated HIB1B brown adipocytes treated with serotonin showed increased brown adipocyte markers alongside increased brain-muscleArnt-like protein1 (Bmal1) andRAR related orphan receptor A (Rora) but decreasednuclear receptor Rev-erbα mRNA levels. BMAL1 overexpression together with serotonin led to significantly lower brown adipocyte markers. Serotonin in the differentiation cocktail led to reduced brown adipocyte markers as well as clock gene expression. After differentiation, serotonin treatment significantly decreased brown adipocyte markers and reduced BMAL1 and RORα but increased REV-ERBα protein levels. Addition of serotonin to the differentiation medium or addition after differentiation reduced activity of calcium/calmodulin-dependent protein kinasetype IIsubunit gamma, which interferes with circadian locomoter output cycles protein kaput (CLOCK):BMAL1 dimerization and transactivation. Clock expression is required at the early stages of differentiation to brown adipocytes, and serotonin interferes with this process by modulating clock functionality. Serotonin interferes with clock functionality by reducing the levels of the active form of calcium/calmodulin-dependent protein kinase typeIIsubunit gamma.

Diurnal protein oscillation profiles in Drosophila head.

Circadian clocks control daily rhythms in physiology, metabolism and behaviour in most organisms. Proteome-wide analysis of protein oscillations is still lacking in Drosophila. In this study, the total protein and phosphorylated protein in Drosophila heads in a 24-h daily time-course were assayed by using the isobaric tags for relative and absolute quantitation (iTRAQ) method, and 10 and 7 oscillating proteins as well as 19 and 22 oscillating phosphoproteins in the w1118 control and ClkJrk mutant strains were separately identified. Lastly, we performed a mini screen to investigate the functions of some oscillating proteins in circadian locomotion rhythms. This study provides the first proteomic profiling of diurnally oscillating proteins in fly heads, thereby providing a basis for further mechanistic studies of these proteins in circadian rhythm.

Dstac is required for normal circadian activity rhythms in Drosophila

ABSTRACTThe genetic, molecular and neuronal mechanism underlying circadian activity rhythms is well characterized in the brain of Drosophila. The small ventrolateral neurons (s-LNVs) and pigment dispersing factor (PDF) expressed by them are especially important for regulating circadian locomotion. Here we describe a novel gene, Dstac, which is similar to the stac genes found in vertebrates that encode adaptor proteins, which bind and regulate L-type voltage-gated Ca2+ channels (CaChs). We show that Dstac is coexpressed with PDF by the s-LNVs and regulates circadian activity. Furthermore, the L-type CaCh, Dmca1D, appears to be expressed by the s-LNVs. Since vertebrate Stac3 regulates an L-type CaCh we hypothesize that Dstac regulates Dmca1D in s-LNVs and circadian activity.

Circadian gene hCLOCK contributes to progression of colorectal carcinoma and is directly regulated by tumor‑suppressive microRNA‑124.

An abundance of studies has demonstrated that disruption of circadian rhythms is one of the factors that may contribute to the initiation and development of human colorectal carcinomas (CRCs). Recently, microRNA-124 has been demonstrated to suppress tumor growth or metastasis of CRCs. However, the mechanisms of cross-talk between microRNA-124 (miR-124) and circadian rhythms in the regulation of CRCs are poorly understood. The present study demonstrated that the protein expression levels of human circadian locomoter output cycles protein kaput (hCLOCK) is significantly increased, while miR-124 is attenuated in high-grade human CRC tissues and in the more invasive colorectal cancer cell lines SW620 and LOVO. It was further demonstrated that hCLOCK is a direct target of miR-124. Upregulation of miR-124 significantly inhibited hCLOCK expression in LOVO cells, and consequently inhibited its promoting effects on the proliferation and migration of LOVO cells. In conclusion, these data revealed that hCLOCK serves an enhancing role, whereas mir-124 serves a suppressive role, in human CRC. Attenuation of miR-124, of which hCLOCK is a direct target, leads to increased hCLOCK expression and disruption of circadian rhythms in CRC.

Expression of circadian clock genes in human colorectal adenoma and carcinoma.

Circadian rhythms are fundamental biological systems in most organisms. Epidemiological and animal studies have demonstrated that disruption of circadian rhythms is linked to tumor progression and mammalian tumorigenesis. However, the clinical significance of in situ clock gene expression in precancerous and cancerous colorectal lesions remains unknown. The present study aimed to investigate mRNA transcript levels of circadian clock genes within human colorectal cancer and adenoma tissue sections. Using in situ hybridization, the expression of key clock genes, including period circadian protein homolog (Per) 1 and 2, cryptochrome 1 (Cry1), circadian locomoter output cycles protein kaput (Clock), brain and muscle ARNT-like protein 1 (Bmal1) and casein kinase 1ε (CK1ε) were retrospectively examined in 51 cases of colorectal carcinoma and 10 cases of adenoma. The expression of clock genes was almost undetectable in the majority of adenomas, whereas positive expression of clock genes was observed in 27–47% of carcinomas. Notably, positive Per1, Per2 and Clock staining in colorectal carcinomas were each significantly associated with a larger tumor size (P=0.012, P=0.011 and P=0.009, respectively). Tumors with positive Per2 and Clock expression tended to exhibit deeper depth of invasion and were generally more advanced than tumors that did not express these genes (P=0.052 and P=0.064, respectively). However, no statistically significant association was observed between clock gene expression and clinicopathological variables, including histopathological differentiation, lymph node metastasis, depth of invasion or disease stage, although Per2-positive tumors tended to be associated with poorer overall survival (P=0.060). The results of the current study suggest that dysregulated expression of clock genes may be important in human colorectal tumorigenesis.

A Peptidergic Circuit Links the Circadian Clock to Locomotor Activity

The mechanisms by which clock neurons in the Drosophila brain confer an ∼24-hr rhythm onto locomotor activity are unclear, but involve the neuropeptide diuretic hormone 44 (DH44), an ortholog of corticotropin-releasing factor. Here we identified DH44 receptor 1 as the relevant receptor for rest:activity rhythms and mapped its site of action to hugin-expressing neurons in the subesophageal zone (SEZ). We traced a circuit that extends from Dh44-expressing neurons in the pars intercerebralis (PI) through hugin+ SEZ neurons to the ventral nerve cord. Hugin neuropeptide, a neuromedin U ortholog, also regulates behavioral rhythms. The DH44 PI-Hugin SEZ circuit controls circadian locomotor activity in a daily cycle but has minimal effect on feeding rhythms, suggesting that the circadian drive to feed can be separated from circadian locomotion. These findings define a linear peptidergic circuit that links the clock to motor outputs to modulate circadian control of locomotor activity.

Circadian Expression of PERIOD and the Pigment-Dispersing Factor in the yellow white mutant Drosophila melanogaster

Daily behavioral andphysiological rhythms in most animals are regulated by a circadian clock. Inthe fruit fly, Drosophila melanogaster, this clock consists of a networkof about 150 cerebral neurons. Different parameters of the fruit fly circadianlocomotion are attributed to specific neuronal subsets and the molecularrhythms of clock genes and proteins within them. To understand the clockmachinery, many clock mutant flies have been used. yellow white (y w) mutation in D. melanogaster cause impairedmelanisation, eye pigmentation loss, and behavioral alterations includingchanges in circadian locomotion. This study investigates the possible molecularbackground for these circadian alterations. Results revealed that in the outputpathway of the clock, the Pigment-Dispersing Factor (PDF) expression wassuppressed in y w mutant fruit flies compared to Canton S (CS) wild-type in the PDF+ clock neurons. Onthe other hand, the degradation of the PERIOD (PER) protein was significantlydelayed in yw mutants and their levels was higher, especially atthe transition from dark to light. The combined effect of elevated PER levelsand suppressed PDF signaling provides an explanation for the delayed morninglocomotor activity peak (M) and advanced evening peak (E) of y w fliescompared to CS.It could be concluded that mutations affecting eye pigmentation like the y w mutationcould have profound effects on the circadian regulation of behavior and theirunderlying molecular oscillations in clock neurons. These effects reduce theplasticity and robustness of the circadian clock and expose the flies to higherlevels of the environmental risk of desiccation.

Increased size due to larval royal jelly exposure does not affect circadian locomotor activity or climbing ability in adult female Drosophila melanogaster

The effects of royal jelly (RJ) appear to be conserved in Drosophila; flies exposed of RJ exhibit increased body size, similar to queen bees. However, in flies and bees, there is evidence that increased body size can lead to impairments to locomotor activity, while RJ may have anti-fatigue properties. Canton-S and Oregon-R Drosophila larvae were raised on media containing 0% or 20% pure RJ. Climbing assays were conducted to assess vertical locomotion. Circadian locomotion was observed using Drosophila Activity Monitors. CS, but not Or-R, raised on RJ were larger compared to controls. Flies exposed to RJ exhibited entrainment and free-running rhythms. The increased size due to RJ exposure in this study had no bearing on circadian locomotor activity or climbing. These results indicate that there is variation among physiological responses to RJ among different strains, but RJ was equally ineffective in affecting locomotor behavior no matter the physiological response.

Monitoring and Analyzing of Circadian and Ultradian Locomotor Activity Based on Raspberry-Pi

A new device based on the Raspberry-Pi to monitor the locomotion of Arctic marine invertebrates and to analyze chronobiologic data has been made, tested and deployed. The device uses infrared sensors to monitor and record the locomotor activity of the animals, which is later analyzed. The software package consists of two separate scripts: the first designed to manage the acquisition and the evolution of the experiment, the second designed to generate actograms and perform various analyses to detect periodicity in the data (e.g., Fourier power spectra, chi-squared periodograms, and Lomb–Scargle periodograms). The data acquisition hardware and the software has been previously tested during an Arctic mission with an arctic marine invertebrate.

Does exercise training impact clock genes in patients with coronary artery disease and type 2 diabetes mellitus?

Recent findings revealed negative effects of deregulated molecular circadian rhythm in coronary artery disease (CAD) and type 2 diabetes mellitus (T2DM). Physical exercise training (ET) has been shown to promote anti-diabetic and anti-atherogenic responses in skeletal muscle of these patients, but the role of the circadian clock-machinery remains unknown. This study investigated whether mRNA expression of clock genes in skeletal muscle of CAD and T2DM patients is influenced by physical ET intervention. Nineteen patients with CAD and T2DM (age 64 ± 5 years) were randomised to either six months of ET (four weeks of in-hospital ET followed by a five-month ambulatory programme) or usual care. At the beginning of the study, after four weeks and after six months parameters of metabolic and cardiovascular risk factors, and physical exercise capacity were assessed. Gene expression was measured in skeletal muscle biopsies by quantitative real-time polymerase chain reaction (PCR). A selection of clock genes and associated components (circadian locomoter output cycle kaput protein (CLOCK), period (PER) 1, cryptochrome (CRY) 2 and aminolevulinate-deltA-synthase-1 (ALAS1)) was reliably measured and used for further analysis. A time-dependent effect in gene expression was observed in CLOCK (p = 0.013) and a significant interaction between time and intervention was observed for ALAS1 (p = 0.032; p = 0.014) as a result of ET. This is the first study to analyse clock gene expression in skeletal muscles of patients with CAD and T2DM participating in a long-lasting exercise intervention. ET, as one of the cornerstones in prevention and rehabilitation of CAD and T2DM, exerts no effects on CLOCK genes but meaningful effects on the clock-associated gene ALAS1.

Role of TGF-β1 in the Behavior Disorders

Transforming growth factor 1 (TGF-1) is an anti-inflammatory cytokine that is expressed in different regions of the mammalian brain, and at all developmental ages. This cytokine can modulate neuron differentiation and survival, and also participate in the tissular response to injury. Based on clinical evidence, different approaches have been used to study the role of TGF-1 on modulating brain function and behavior. Here, we review evidence showing a role of TGF-1 in circadian rhythms, locomotion, sociability and depression-related behaviors. For these behaviors, suprachiamatic, hippocampal and cerebellar expression of TGF-1 have been manipulated. Further studies are required to extend these results to other brain regions and different behaviors, but so far evidence points to a role of TGF-1 on behavior disorders such as schizophrenia, depression and autism.

Evidence for clock genes circadian rhythms in human full-term placenta

Biological rhythms are driven by endogenous biological clocks; in mammals, the master clock is located in the suprachiasmatic nucleus (SCN) of the hypothalamus. This master pacemaker can synchronize other peripheral oscillators in several tissues such as some involved in endocrine or reproductive functions. The presence of an endogenous placental clock has received little attention. In fact, there are no studies in human full-term placentas. To test the existence of an endogenous pacemaker in this tissue we have studied the expression of circadian locomoter output cycles kaput (Clock), brain and muscle arnt-like (Bmal)1, period (Per)2, and cryptochrome (Cry)1 mRNAs at 00, 04, 08, 12, 16, and 20 hours by qPCR. The four clock genes studied are expressed in full-term human placenta. The results obtained allow us to suggest that a peripheral oscillator exists in human placenta. Data were analyzed using Fourier series where only the Clock and Bmal1 expression shows a circadian rhythm.