Cardiopoietic programming of embryonic stem cells for tumor-free heart repair

Embryonic stem cells have the distinct potential for tissue regeneration, including cardiac repair. Their propensity for multilineage differentiation carries, however, the liability of neoplastic growth, impeding therapeutic application. Here, the tumorigenic threat associated with embryonic stem cell transplantation was suppressed by cardiac-restricted transgenic expression of the reprogramming cytokine TNF-α, enhancing the cardiogenic competence of recipient heart. The in vivo aptitude of TNF-α to promote cardiac differentiation was recapitulated in embryoid bodies in vitro. The procardiogenic action required an intact endoderm and was mediated by secreted cardio-inductive signals. Resolved TNF-α–induced endoderm-derived factors, combined in a cocktail, secured guided differentiation of embryonic stem cells in monolayers produce cardiac progenitors termed cardiopoietic cells. Characterized by a down-regulation of oncogenic markers, up-regulation, and nuclear translocation of cardiac transcription factors, this predetermined population yielded functional cardiomyocyte progeny. Recruited cardiopoietic cells delivered in infarcted hearts generated cardiomyocytes that proliferated into scar tissue, integrating with host myocardium for tumor-free repair. Thus, cardiopoietic programming establishes a strategy to hone stem cell pluripotency, offering a tumor-resistant approach for regeneration

Store-operated Ca2+ entry supports contractile function in hearts of hibernators.

Hibernators have a distinctive ability to adapt to seasonal changes of body temperature in a range between 37°C and near freezing, exhibiting, among other features, a unique reversibility of cardiac contractility. The adaptation of myocardial contractility in hibernation state relies on alterations of excitation contraction coupling, which becomes less-dependent from extracellular Ca2+ entry and is predominantly controlled by Ca2+ release from sarcoplasmic reticulum, replenished by the Ca2+-ATPase (SERCA). We found that the specific SERCA inhibitor cyclopiazonic acid (CPA), in contrast to its effect in papillary muscles (PM) from rat hearts, did not reduce but rather potentiated contractility of PM from hibernating ground squirrels (GS). In GS ventricles we identified drastically elevated, compared to rats, expression of Orai1, Stim1 and Trpc1/3/4/5/6/7 mRNAs, putative components of store operated Ca2+ channels (SOC). Trpc3 protein levels were found increased in winter compared to summer GS, yet levels of Trpc5, Trpc6 or Trpc7 remained unchanged. Under suppressed voltage-dependent K+, Na+ and Ca2+ currents, the SOC inhibitor 2-aminoethyl diphenylborinate (2-APB) diminished whole-cell membrane currents in isolated cardiomyocytes from hibernating GS, but not from rats. During cooling-reheating cycles (30°C-7°C-30°C) of ground squirrel PM, 2-APB did not affect typical CPA-sensitive elevation of contractile force at low temperatures, but precluded the contractility at 30°C before and after the cooling. Wash-out of 2-APB reversed PM contractility to control values. Thus, we suggest that SOC play a pivotal role in governing the ability of hibernator hearts to maintain their function during the transition in and out of hibernating states

Biodiversity of Coleoptera (Insecta) in the Middle and Lower Volga Regions (Russia)

(1) Background: The conservation of entomofauna in individual macroregions requires efforts to study the distribution and abundance of insects. For this purpose, databases are created that enumerate this information. Such databases, with the processing of significant factual material, make it possible to objectively assess the status of a species and, if necessary, take measures for its protection. The aim of the paper is to describe the modern Coleoptera fauna in nine regions of Russia on the basis of a recently published dataset. (2) Methods: We conducted our own studies in 1994, 1996, 1998–2003 and 2005–2022. The dataset also includes data from museum specimens from other years. We used a variety of methods, such as sifting through litter, searching under the bark of trees and stumps, trapping by light, soil traps, beer traps, window traps, etc. For each observation, the coordinates of the find, the number of individuals observed and the date were recorded. (3) Results: The dataset contains data on 1469 species and subspecies of Coleoptera from 85 families found in the Volga Region. In total, there are 31,433 samples and 9072 occurrences in the dataset. (4) Conclusions: The largest families in terms of species diversity are Curculionidae (202 species), Carabidae (145 species) and Chrysomelidae (142 species). There are 54 species of Coleoptera with a northern range boundary in the macroregion, two species with a southern range boundary and one species with an eastern range boundary. Twenty-one invasive Coleoptera species have been recorded in the macroregion

Biodiversity of Coleoptera (Insecta) in the Middle and Lower Volga Regions (Russia)

(1) Background: The conservation of entomofauna in individual macroregions requires efforts to study the distribution and abundance of insects. For this purpose, databases are created that enumerate this information. Such databases, with the processing of significant factual material, make it possible to objectively assess the status of a species and, if necessary, take measures for its protection. The aim of the paper is to describe the modern Coleoptera fauna in nine regions of Russia on the basis of a recently published dataset. (2) Methods: We conducted our own studies in 1994, 1996, 1998–2003 and 2005–2022. The dataset also includes data from museum specimens from other years. We used a variety of methods, such as sifting through litter, searching under the bark of trees and stumps, trapping by light, soil traps, beer traps, window traps, etc. For each observation, the coordinates of the find, the number of individuals observed and the date were recorded. (3) Results: The dataset contains data on 1469 species and subspecies of Coleoptera from 85 families found in the Volga Region. In total, there are 31,433 samples and 9072 occurrences in the dataset. (4) Conclusions: The largest families in terms of species diversity are Curculionidae (202 species), Carabidae (145 species) and Chrysomelidae (142 species). There are 54 species of Coleoptera with a northern range boundary in the macroregion, two species with a southern range boundary and one species with an eastern range boundary. Twenty-one invasive Coleoptera species have been recorded in the macroregion

2-APB- and CPA-induced modulation of ground squirrel PM contractility during cooling-reheating cycles.

<p>PM contractility acquired at 0.1Hz stimulation frequency in control (<b>A</b>), in the presence of 2-APB (<b>B</b>) or CPA (<b>C</b>). The temperature of bath solutions was changed at the approximate rate 0.1–0.2°C/min. Blue solid bars marked by asterisks (<b>B</b>) indicate 2-APB-induced inhibition of PM contractility before and after cooling, respectively. The profiles of temperature changes and drug application are shown by corresponding colored gradient bars and solid lines above the traces. (<b>D</b>) Summarized statistics for (<b>A</b>), (<b>B</b>) and (<b>C</b>) at the indicated temperatures; *, denotes statistically significant differences (P < 0.05; n = 5, 4 and 3 in control, in the presence of 2-APB and CPA groups, respectively), estimated using the single group t-test compared to peak force of contraction before cooling (100%).</p

Primer sequences for PCR amplification.

<p>Primer sequences for PCR amplification.</p

Temperature-dependent adaptation of papillary muscle contractility in ground squirrel and rat hearts.

<p>(<b>A</b>) representative relative isometric contractile forces measured at 0.1 Hz stimulation frequency in isolated papillary muscles from ground squirrel (solid lines) and rat (dotted lines) hearts at different temperatures (as indicated). Contractile forces in both species were plotted relative to the values obtained at 30°C. (<b>B</b>) Summary statistics for the contractility of papillary muscle under conditions indicated in (<b>A</b>); *, denotes statistically significant differences (P<0.05, n shown in parenthesis) estimated using the single group t-test compared to maximal force of contraction before cooling (100%). (<b>C</b> and <b>D</b>) FFR constructed at 30°C before cooling to 10°C and after reheating; point values were obtained by normalizing measured maximal contraction forces to the averaged value at 0.1 Hz before cooling; *, denotes statistically significant differences between values before cooling and after reheating (P<0.05; n = 7 in ground squirrels, and n = 4 in rats).</p

Ca²⁺ store-dependent regulation of contractile function of ground squirrel versus rat PM.

<p>(<b>A</b> and <b>B</b>) Representative recordings of ground squirrel and rat PM contractility under transition from nominal 1.8 mM Ca²⁺ to Ca²⁺-free Tyrode solution at 0.1 Hz stimulation frequency. (<b>C</b>) Same protocol in ground squirrel PM at doubled external Ca²⁺ levels also increase the force of contraction and further enhanced the amplitude of resting tension. Arrows in panels point to an increase in resting tension observed in ground squirrel but not rat PM. (<b>D</b> and <b>E</b>) Comparison of averaged relative force of contraction and relative resting tension (n = at least 3 in each experimental group) measured in the presence of CPA relative to control force of contraction before treatments. *, denotes statistically significant difference (P<0.05) defined by single group t-test comparing values with 1 in panel (<b>D</b>) and with 0 in panel (<b>E</b>). ‡, denotes significant difference (P<0.05) between relative resting tensions at 1.8 mM versus 3.6 mM of external Ca²⁺ in ground squirrel PM. (<b>F</b>) The profile of changes in the force of contraction and resting tension under manipulations with external Ca²⁺ and CPA was unaffected by the blocker of L-type Ca²⁺ channels, nifedipine, in line with moderate dependence of PM contractility on voltage-gated Ca²⁺ entry at low stimulation frequencies (<b>G</b>; *, P<0.05 for effects of nifedipine compared to corresponding controls; n = 4 in each group). (<b>H</b>) In ground squirrel PM, 2-APB reversed the contraction force potentiated by CPA to value below control. The averaged (n = 3) relative force of contraction is shown in panel (<b>D</b>).</p

Effects of 2-APB on membrane currents in isolated cardiomyocytes and PM contractility in ground squirrel and rat hearts.

<p>(<b>A</b>) Representative voltage-current relationships of whole-cell membrane currents in a ground squirrel cardiomyocyte measured in response to a voltage ramp of 133.3 mV/s in the absence and presence of 2-APB. 2-APB-sensitive currents were obtained by subtraction of currents measured in the presence of 2-APB from control values at each membrane potential. (<b>B</b>) Time course and summary statistics of reversible 2-APB-induced inhibition of ground squirrel PM contractility measured at 0.1 Hz stimulation frequency. (<b>C</b>) FFR in ground squirrel PM in the absence (n = 8–9) and presence (n = 6) of 2-APB (20 μM); *, denotes statistically significant difference with P<0.05. (<b>D</b>) Representative voltage-current relationships of whole-cell membrane currents in a rat cardiomyocyte detected in response to a voltage ramp of 153.3 mV/s in the absence and presence of 2-APB. 2-APB-induced currents were obtained by subtraction of currents measured in the presence of 2-APB from control values at each membrane potential. (<b>E</b>) Representative recordings at 0.3 Hz stimulation frequency exemplifying the incidents of contractile dysfunction and arrhythmia induced by 2-APB in rat, but not in ground squirrel PM.</p