Muscle mass,structural and functional investigations of senescence-accelerated mouse P8 (SAMP8)

Sarcopenia is an age-related systemic syndrome with progressive deterioration in skeletal muscle functions and loss in mass. Although the senescence-accelerated mouse P8 (SAMP8) was reported valid for muscular ageing research, there was no report on the details such as sarcopenia onset time. Therefore, this study was to investigate the change of muscle mass, structure and functions during the development of sarcopenia. Besides the average life span, muscle mass, structural and functional measurements were also studied. Male SAMP8 animals were examined at month 6, 7, 8, 9, and 10, in which the right gastrocnemius was isolated and tested for ex vivo contractile properties and fatigability while the contralateral one was harvested for muscle fiber cross-sectional area (FCSA) and typing assessments. Results showed that the peak of muscle mass appeared at month 7 and the onset of contractility decline was observed from month 8. Compared with month 8, most of the functional parameters at month 10 decreased significantly. Structurally, muscle fiber type IIA made up the largest proportion of the gastrocnemius, and the fiber size was found to peak at month 8. Based on the altered muscle mass, structural and functional outcomes, it was concluded that the onset of sarcopenia in SAMP8 animals was at month 8. SAMP8 animals at month 8 should be at pre-sarcopenia stage while month 10 at sarcopenia stage. It is confirmed that SAMP8 mouse can be used in sarcopenia research with established time line in this study.     

Attenuated Bordetella pertussis Protects against Highly Pathogenic Influenza A Viruses by Dampening the Cytokine Storm

The threat of a pandemic spread of highly virulent influenza A viruses currently represents a top global public health problem. Mass vaccination remains the most effective way to combat influenza virus. However, current vaccination strategies face the challenge to meet the demands in a pandemic situation. In a mouse model of severe influenza virus-induced pneumonitis, we observed that prior nasal administration of an attenuated strain of Bordetella pertussis (BPZE1) provided effective and sustained protection against lethal challenge with two different influenza A virus subtypes. In contrast to most cross-protective effects reported so far, the protective window offered upon nasal treatment with BPZE1 lasted up to at least 12 weeks, suggesting a unique mechanism(s) involved in the protection. No significant differences in viral loads were observed between BPZE1-treated and control mice, indicating that the cross-protective mechanism(s) does not directly target the viral particles and/or infected cells. This was further confirmed by the absence of cross-reactive antibodies and T cells in serum transfer and in vitro restimulation experiments, respectively. Instead, compared to infected control mice, BPZE1-treated animals displayed markedly reduced lung inflammation and tissue damage, decreased neutrophil infiltration, and strong suppression of the production of major proinflammatory mediators in their bronchoalveolar fluids (BALFs). Our findings thus indicate that protection against influenza virus-induced severe pneumonitis can be achieved through attenuation of exaggerated cytokine-mediated inflammation. Furthermore, nasal treatment with live attenuated B. pertussis offers a potential alternative to conventional approaches in the fight against one of the most frightening current global public health threats.Influenza virus pandemics are unpredictable but recurring events that can have severe consequences on societies worldwide. In the 20th century, three novel influenza virus strains emerged, causing the 1918, 1957, and 1968 pandemics, the most devastating being the 1918 Spanish flu that led to an estimated 50 million deaths (47). The recent spread of highly pathogenic avian influenza (HPAI) H5N1 virus across parts of Asia, Europe, and the Middle East, with an overall fatality rate of over 60% for humans, as well as the rapid pandemic spread of a novel influenza A virus of the H1N1 subtype, has caused worldwide concern about a potential remake of the 1918 disaster (8).Severe complications arising from pandemic influenza or HPAI H5N1 viruses are associated with rapid, massive inflammatory cell infiltration, resulting in acute respiratory distress, and reactive hemophagocytosis with multiple organ involvement. Both the 1918 Spanish influenza virus and HPAI H5N1 induce a cytokine storm characterized by an exaggerated production of inflammatory cytokines and chemokines in the serum and lungs caused by uncontrolled activation of the host''s innate immune system. This triggers massive pulmonary edema, primary and/or secondary pneumonia, and alveolar hemorrhage with acute bronchopneumonia (4, 12, 24, 27, 37, 40, 43, 44).The relationship between mortality, viral load, and immunopathology during influenza virus infection remains elusive and somewhat controversial. Some studies suggest that severe lung immunopathology is a direct consequence of a high viral load that the host is unable to resolve (12, 13), whereas others have reported that influenza virus-induced mortality is not a direct function of viral burden but a consequence of immune-mediated pathology (9, 11). Moreover, the picture is further complicated by the fact that different highly virulent influenza A viruses may induce distinct pathological signatures and lead to different courses of acute respiratory distress syndrome, refuting the hypothesis of a single, universal cytokine storm underlying all fatal influenza virus diseases (16).Currently, vaccination remains the cornerstone of influenza virus prevention. However, due to constant antigenic drift and shift of the two major viral surface proteins hemagglutinin (HA) and neuraminidase (NA) (7), influenza virus vaccines must be reformulated each year in order to match the circulating subtypes (41). The potential emergence of an influenza virus pandemic at any time, combined with limited vaccine supplies, has rendered global vaccination strategies difficult. Therefore, a universal influenza virus vaccine that can provide protection against different variants or strains and thus not require frequent updates is highly desirable.Here, we report that nasal administration of a recently developed live attenuated Bordetella pertussis vaccine strain, named BPZE1 (35), provides effective and sustained protection against lethal challenge with mouse-adapted H3N2 or H1N1 (A/PR/8/34) influenza A viruses. We demonstrate that the protective mechanism(s) does not target the viral particles or the infected host cells but controls the influenza virus-mediated inflammation by dampening the cytokine storm. As BPZE1 has recently entered phase I safety trials with humans (http://www.child-innovac.org), our observations support the potential application of this vaccine strain as a universal prophylactic treatment against highly pathogenic influenza A viruses.     

The retina-attached SCN slice preparation: an in vitro mammalian circadian visual system

The suprachiasmatic nucleus (SCN), the mammalian circadian pacemaker, receives information about ambient light levels through the retinohypothalamic tract. This information resets the molecular clock of SCN neurons, thereby entraining overt animal behavior and physiology to the solar cycle. Progress toward functional characterization of retinal influences on the SCN has been hampered by limitations of established experimental paradigms. To overcome this hurdle, the authors have developed a novel in vitro preparation of the rat retinohypothalamic circuit that maintains functional connectivity between the retinas and the SCN. This method permits whole-cell patch-clamp recordings from visually identified, light-responsive SCN neurons. Using this preparation, the authors have found that in the SCN, light-evoked responses are partly driven by the melanopsin photosensory system of the intrinsically photosensitive retinal ganglion cells and that SCN neurons exhibit light adaptation. The authors have also been able to generate this preparation from mice, demonstrating the feasibility of applying this method to transgenic mice.     

Effects of des-aspartate-angiotensin I on neointima growth and cardiovascular hypertrophy

The in vitro anti-hypertrophic and hyperplastic actions of des-aspartate-angiotensin I (DAA-I) on cultured cardiovascular cells have been demonstrated in earlier experiments. The present study investigated its effects on the development of neointima in balloon catheter-injured carotid artery of the Sprague-Dawley (SD) rat and the development of cardiovascular hypertrophy in the spontaneously hypertensive rat. Treatment with i.v. DAA-I for 14 days post-injury dose-dependently attenuated the development of neointima. The maximum effect was obtained at 34 pmol/kg/day. The data support the possibility that endogenous angiotensins could inhibit neointima growth. This opens up avenues for their therapeutic elevation in combating neointima-related restenosis of which current drugs are not fully effective in suppressing. Five-week-old pre-hypertensive SHR, when orally administered with a dose of 769 nmol/kg/day DAA-I for a duration of 47 weeks, showed significant reduction in the development of cardiac and vascular hypertrophy compared to the untreated controls. Similar treatment with DAA-I had no effect on the Wistar Kyoto rats. The present findings support the contention that, besides angiotensin II, other endogenous angiotensins are also involved in the regulation and/or pathophysiology of the cardiovascular system.     

Photoreceptor adaptation in intrinsically photosensitive retinal ganglion cells

A rare type of mammalian retinal ganglion cell (RGC) expresses the photopigment melanopsin and is a photoreceptor. These intrinsically photosensitive RGCs (ipRGCs) drive circadian-clock resetting, pupillary constriction, and other non-image-forming photic responses. Both the light responses of ipRGCs and the behaviors they drive are remarkably sustained, raising the possibility that, unlike rods and cones, ipRGCs do not adjust their sensitivity according to lighting conditions ("adaptation"). We found, to the contrary, that ipRGC sensitivity is plastic, strongly influenced by lighting history. When exposed to a constant, bright background, the background-evoked response decayed, and responses to superimposed flashes grew in amplitude, indicating light adaptation. After extinction of a light-adapting background, sensitivity recovered progressively in darkness, indicating dark adaptation. Because these adjustments in sensitivity persisted when synapses were blocked, they constitute "photoreceptor adaptation" rather than "network adaptation." Implications for the mechanisms generating various non-image-forming visual responses are discussed.     

Memories of Ray Wu by a Colleague

I first met Ray Wu in the spring of 1977 during my inter-view at Cornell where he was the Chair of the Section of Biochemistry, Molecular and Cell Biology. The meeting was brief and unremarkable but it achieved what it was meant to achieve. After I joined the Section of BMCB at Cornell as assistant professor that fall, I soon appreciated that that     

Cardioprotective effect of des-Aspartate-angiotensin-I (DAA-I) on cytokine gene expression profile in ligation model of myocardial infarction

We investigate the influence of des-Aspartate-angiotensin-I (DAA-I) on the cytokine expression profile in a rodent model of myocardial infarction. Myocardial infarction model was created in female Wistar rats by coronary artery ligation. Animals were randomized to receive intravenously either a daily dose of 1.2 mug DAA-I/kg body weight (group 1; n = 60) or saline (group 2; n = 60) for 14 days after infarction. Heart function was assessed by echocardiography. Animals were euthanized at 1, 3, 7, 14 and 31 days. Morphometric analysis using tetrazolium chloride staining revealed that infarct size was reduced by 32.2% (p < 0.05) in group 1 after 14 days of DAA-I treatment. Left ventricular ejection fraction in group 1 improved significantly (73.4%) as compared to group 2 (47.7%; p < 0.001). Immunostaining for immune cells at the infarct site showed that CD8+ lymphocytes infiltration at the infarct site declined in group 1 (15 +/- 5 cells) as compared to group 2 (50 +/- 6 cells; p < 0.001). Infiltration of monocytes and macrophages remained high at day 14 in group 2 (126 +/- 40 cells) as compared to group 1 (49 +/- 11 cells; p = 0.006). Multiplex PCR was done for differential gene expression of various pro-inflammatory cytokines. IL-6, TNF-alpha, TGF-beta and GM-CSF expression were significantly down-regulated in the infarct, peri-infarct and contra-lateral zones of the left ventricle in group 1 as compared to group 2. IL-6, TGF-beta and GM-CSF expression started to decline from day 1 of DAA-I treatment while TNF-alpha expression only reduced after 7 days of DAA-I treatment. We conclude that DAA-I prevented infarct expansion through suppression of inflammatory cytokines and immune cell infiltration in the infarct region.     

Local Enhancement in Mud-Puddling Swallowtail Butterflies (Battus philenor and Papilio glaucus)

Male butterflies aggregate at moist soil to acquire nutrients, a phenomenon termed “mud-puddling.” We studied the attraction of free-flying Papilio glaucus and Battus philenor swallowtails to dead decoys of those two species at artificial puddles moistened with NaCl solution. Both species landed preferentially at puddles with a decoy present rather than at unbaited puddles, demonstrating very strong local enhancement, a form of social facilitation. Papilio glaucus were attracted only to intraspecific decoys, whereas Battus philenor exhibited both intraspecific and interspecific attraction. Circular discs cut from the hindwings of male Battus were highly attractive to male Battus but completely unattractive to Papilio glaucus. The visual cues attractive to males in their search for salts differ between these two swallowtail species for unexplained reasons.